A Warming World Means Vaccination is More Important Than Ever

“The climate crisis threatens to undo the last fifty years of progress in development, global health, and poverty reduction, and to further widen existing health inequalities between and within populations.”1

With July 2023 confirmed as the hottest month on record2, the impacts of climate change are becoming impossible to ignore. In addition to rising temperatures, climate change is also responsible for increasingly frequent extreme weather events like intense storms, catastrophic floods, and record-breaking heat waves. A growing body of evidence suggests that the consequences of climate change pose a major threat not only to the planet, but also to human health.

Altogether, climate change is expected to cause around 250,000 excess deaths per year between 2030 and 2050 due to malnutrition, malaria, diarrhea, and heat stress alone1. In addition to the excess mortality that is directly attributable to natural disasters, the wide-ranging effects of climate change can also indirectly contribute to illness and death through several pathways. Warm, dry conditions trigger more frequent wildfires3, which in turn contribute to dangerous levels of air pollution4. The stress of living through an extreme weather event and the resulting loss of critical resources has been linked with poor mental health5. Furthermore, climate change is expected to increase the prevalence of several vaccine-preventable diseases, such as malaria, cholera, and typhoid, thanks to the expansion of mosquito habitats, scarcity of clean water, and disruptions to routine immunization, among others6.

No one is safe from the effects of climate change, but its impact reflects deep inequities. Already marginalized communities – particularly those in developing countries – will be disproportionately affected due to existing health disparities and insufficient health system infrastructure7. To minimize climate change-related health impacts, equitable access to vaccines must be a priority, especially for those who will be most affected in the years to come.

Rising Temperatures Increase Disease Transmission

In August 2023, global temperatures were approximately 1.5°C above preindustrial levels8. In addition to the illnesses and deaths caused directly by these dangerously high temperatures, such as those related to heat stroke9, collateral effects also include increased transmission of a number of vaccine-preventable diseases.

Warmer winters and hotter summers are expected to increase the evaporation of water sources, endangering the availability of safe, clean water and increasing the risk of diarrheal diseases10. This includes cholera, which has recently seen a global surge: The WHO reported 472,697 cases of cholera in 2022, nearly double the number reported in 202111. Rising temperatures reduce the availability of high-quality crops12, threatening food security and leading to dangerous malnutrition that weakens a child’s immune system and increases the risk of infectious disease.

Undernourished child cycle
Source: The Value of Immunization Compendium of Evidence – The vicious cycle of undernutrition and infectious disease: How does it work and what role do vaccines play?

An analysis of 14 countries in sub-Saharan Africa13 demonstrated that for every 1°C increase in average maximum temperature, the prevalence of diarrhea increased by about 1%. The reasons for this association are not entirely clear, but researchers point to the impact of heat on the growth and survival of diarrhea-causing bacteria, as well as the potential for heat-related changes in hygiene or food storage. This increase in disease burden may significantly impact vulnerable populations, especially young children, as diarrhea is currently the second most deadly infectious disease worldwide and kills over 480,000 children under 5 each year14. We already have the means to prevent rotavirus infection, the leading cause of diarrhea-related mortality among children around the world – a 2018 analysis estimated that if 100% of children globally had access to rotavirus vaccination, more than 83,000 child deaths could be prevented in a single year15 – yet millions of children around the world are still unprotected against this disease16. As global temperatures continue to rise, efforts to increase access to lifesaving rotavirus vaccines will remain critical.

Rising Temperatures graph

Temperature changes are also expected to impact transmission of vector-borne diseases, including malaria. About 80% of the world’s population lives in a region that is at risk of at least one vector-borne disease17, and this number could grow as temperatures continue to rise. The malaria parasite develops more quickly at higher temperatures, increasing the chance that a mosquito will survive long enough to transmit the disease18. Additionally, areas that are presently too cold for malaria transmission may warm up enough to allow malaria parasites to survive, exposing new populations to this deadly disease. One recent analysis estimated that around 1.4 billion additional people will be at risk of malaria and dengue in urban areas in Africa and southeast Asia due to changes in climate19. On the other hand, areas where malaria is currently being transmitted may become too warm, which could actually decrease incidence of the disease. Controlling malaria is already complex, but additional climate-related factors such as temperature, rainfall, and humidity may be important considerations for preventing outbreaks.

The Dangerous Consequences of Floods and Droughts

“Climate change is exacerbating both water scarcity and water-related hazards (such as floods and droughts), as rising temperatures disrupt precipitation patterns and the entire water cycle.”20

Between 2001–2018, nearly two-thirds of natural disasters were water-related21, and floods and droughts are only expected to become more intense and more frequent as climate change worsens. These events threaten the availability of safe drinking water and can increase transmission of enteric diseases. For example, both droughts and floods have been found to be significantly associated with cholera outbreaks in sub-Saharan Africa22; in this region, a cholera outbreak can be expected in 1 out of every 3 droughts. During a drought, communities searching for water can be forcibly displaced, often to overcrowded refugee camps with poor sanitation and limited access to cooking tools, increasing the risk of contamination and disease transmission.

Conversely, floodwater can overflow sewage systems and contaminate drinking water23. This contaminated water can also destroy WASH facilities, further putting communities at risk of disease transmission. Additionally, the heavy rainfall and stagnant water associated with flooding can create new mosquito habitats and increase breeding. In 2007, for example, areas in China impacted by flooding saw significantly higher numbers of cases of both malaria and diarrhea than non-flood-affected areas24. Lastly, floods and other disasters can seriously disrupt the delivery of health services, including vaccination25. Not only can flood water damage hospitals and health clinics, making it difficult or even impossible to provide routine immunization services, but it can also block roads, potentially leading to supply chain gaps that can impact the availability of vaccines and other critical medical supplies.

Infographic showing links between flooding, enteric disease, new mosquito habitats and damage to health facilities

Disproportionate Impact to Disadvantaged Populations

Every year, approximately 21.5 million people around the world26 are forced to leave their homes due to climate-related disasters like floods, storms, wildfires, and extreme temperatures, and this number is only expected to continue growing27. These individuals are often referred to as “climate refugees”, though this includes those internally displaced within their own countries as well as those pushed across borders to seek safety. Climate-related displacement disproportionately impacts those living in low-resource settings, who are less able to prepare for and withstand natural disasters. Even within low- and middle-income countries (LMICs), climate change is more likely to impact those who are already most deprived. According to an analysis in Pakistan, the regions with worse socioeconomic conditions are also the most vulnerable to climate change28. The same analysis also found that some regions which should be most exposed to climate change due to their precipitation and temperature patterns are actually less vulnerable, most likely because their populations have higher socioeconomic status and thus a higher capacity to adapt, suggesting that strengthening a community’s resilience is one potential solution to fight the impacts of climate change.

In addition to equity considerations, forced migration can also lead to increased risks of vaccine-preventable disease outbreaks. Disruption to health services, malnutrition, overcrowded settlements, and insufficient sanitation resources all contribute to infectious diseases, such as pneumonia and diarrhea, which are the leading causes of death during humanitarian emergencies29. Vaccination programs that target measles, S. pneumoniae, H. influenzae type-b, and rotavirus have already been recognized as critical tools for reducing the health impacts of complex humanitarian emergencies.

Mitigating the Impact of Climate Change with Vaccines

At this point, the impact of climate change is inevitable, but there are steps we can take to mitigate its effects on human health. We must strengthen efforts to increase access to vaccines for diseases that will become more prevalent as extreme weather events continue, prioritizing disadvantaged communities that will be hardest hit by climate-related disasters. Beyond vaccine introduction, we must work to make sure that adequate supplies are made available to those who need them most. For example, millions of doses of life-saving malaria vaccines30 are being rolled out in Africa over the next two years, but there is still significant work to be done to meet the global demand for these vaccines and to ensure that LMICs can afford them31. Similarly, the global supply of oral cholera vaccine (OCV) is currently unable to meet the needs of more and more frequent cholera outbreaks and must be allocated equitably32.

Over the last decade, enormous victories have been won in protecting children from preventable illnesses. As climate change has been recognized as a serious threat to public health, policymakers must take decisive action now to safeguard vulnerable populations from potentially catastrophic infectious diseases and counteract immunization backsliding.

Additional Reading

Will the Earth’s changing climate make TB spread faster? [Bhekisisa Centre for Health Journalism]

Children displaced in a changing climate: Preparing for a future that’s already underway [UNICEF]

Vaccines for a sustainable planet [Science Translational Medicine]


  1. World Health Organization. Climate change and health. Updated 30 October 2021. Accessed September 28, 2023. https://www.who.int/news-room/fact-sheets/detail/climate-change-and-health
  2. World Meteorological Organization. July 2023 confirmed as hottest month on record. 14 August 2023. https://public.wmo.int/en/media/news/july-2023-confirmed-hottest-month-record
  3. National Oceanic and Atmospheric Administration. Wildfire climate connection. Updated 24 July 2023. Accessed September 28, 2023. https://www.noaa.gov/noaa-wildfire/wildfire-climate-connection
  4. World Health Organization. Wildfires. Accessed September 28, 2023. https://www.who.int/health-topics/wildfires
  5. Cianconi P, Betro S, Janiri L. The Impact of Climate Change on Mental Health: A Systematic Descriptive Review. Frontiers in Psychiatry. Mar 6 2020;11(74). doi:10.3389/fpsyt.2020.00074
  6. Joi P. Five key links between climate change and health. VaccinesWork blog. 2023. https://www.gavi.org/vaccineswork/five-key-links-between-climate-change-and-health
  7. Byers E, Gidden M, Leclere D, et al. Global exposure and vulnerability to multi-sector development and climate change hotspots. Environmental Research Letters. 31 May 2018. doi:10.1088/1748-9326/aabf45
  8. World Meteorological Organization. Earth had hottest three-month period on record, with unprecedented sea surface temperatures and much extreme weather. 6 September 2023, 2023. https://public.wmo.int/en/media/press-release/earth-had-hottest-three-month-period-record-unprecedented-sea-surface
  9. World Health Organization. Heatwaves. Accessed September 28, 2023. https://www.who.int/health-topics/heatwaves
  10. International Federation of Red Cross and Red Crescent Societies, 2021. Climate Change Impacts on Health: Malawi Assessment. April 2021.
  11. World Health Organization. Weekly Epidemiological Record. Vol. 38. 2023:431-452. 22 September 2023.
  12. Zhao C, Liu B, Piao S, et al. Temperature increase reduces global yields of major crops in four independent estimates. Proceedings of the National Academy of Sciences. 2017;114(35):9326-9331. doi:10.1073/pnas.1701762114
  13. Bandyopadhyay S, Kanji S, Wang L. The impact of rainfall and temperature variation on diarrheal prevalence in Sub-Saharan Africa. Applied Geography. April 2012;33:63-72. doi:10.1016/j.apgeog.2011.07.017
  14. International Vaccine Access Center (IVAC), Johns Hopkins Bloomberg School of Public Health. (2022). Pneumonia and Diarrhea Progress Report 2022.
  15. Troeger C, Khalil IA, Rao PC, et al. (2018). Rotavirus vaccination and the global burden of rotavirus diarrhea among children younger than 5 years. JAMA Pediatrics. Oct 2018;172(10). doi: 10.1001/jamapediatrics.2018.1960
  16. International Vaccine Access Center (IVAC), Johns Hopkins Bloomberg School of Public Health. VIEW-hub. www.view-hub.org. Accessed 10/19/2023.
  17. Alonso P, Engels D, Reeder J. Renewed push to strengthen vector control globally. The Lancet. June 10 2017;389(10086):2270-2271. doi:10.1016/S0140-6736(17)31376-4
  18. Agyekum T, Botwe P, Arko-Mensah J, et al. A Systematic Review of the Effects of Temperature on Anopheles Mosquito Development and Survival: Implications for Malaria Control in a Future Warmer Climate. International Journal of Environmental Research and Public Health. 7 July 2021;18(14).doi:10.3390/ijerph18147255
  19. Colon-Gonzalez FJ, Sewe MO, Tompkins AM, et al. Projecting the risk of mosquito-borne diseases in a warmer and more populated world: a multi-model, multi-scenario intercomparison modelling study. The Lancet Planetary Health. July 2021;5(7):E404-E414. doi:10.1016/S2542-5196(21)00132-7
  20. United Nations. Water – at the center of the climate crisis. Accessed September 28, 2023. https://www.un.org/en/climatechange/science/climate-issues/water?gclid=CjwKCAjw3oqoBhAjEiwA_UaLtjFAZ_AFhkgP6lr0YAg7vlwTwZwUbsZa9T-pBajg0zu2QyOFKT8CpBoC3RIQAvD_BwE
  21. UNICEF. Water and the global climate crisis: 10 things you should know. Updated 2 March 2023. https://www.unicef.org/stories/water-and-climate-change-10-things-you-should-know
  22. Rieckmann A, Tamason CC, Gurley ES, et al. Exploring Droughts and Floods and Their Association with Cholera Outbreaks in Sub-Saharan Africa: A Register-Based Ecological Study from 1990 to 2010. The American Journal of Tropical Medicine and Hygiene. 2018;98(5):1269-1274. doi:10.4269/ajtmh.17-0778
  23. ten Veldhuis JAE, Clemens FHL, Sterk G, et al. Microbial risks associated with exposure to pathogens in contaminated urban flood water. Water Research. May 2010;44(9):2910-2918. doi:10.1016/j.watres.2010.02.009
  24. Gao L, Zhang Y, Ding G, et al. Identifying Flood-Related Infectious Diseases in Anhui Province, China: A Spatial and Temporal Analysis. The American Journal of Tropical Medicine and Hygiene. 2016;94(4):741-749. doi:10.4269/ajtmh.15-0338
  25. Pradhan NA, Najmi R, Fatmi Z. District health systems capacity to maintain healthcare service delivery in Pakistan during floods: A qualitative study. International Journal of Disaster Risk Reduction. August 2022;78. doi:10.1016/j.ijdrr.2022.103092
  26. UNHCR. Frequently asked questions on climate change and disaster displacement. Updated 6 November 2016. Accessed September 28, 2023. https://www.unhcr.org/uk/news/stories/frequently-asked-questions-climate-change-and-disaster-displacement
  27. Institute for Economics & Peace. Over one billion people at threat of being displaced by 2050 due to environmental change, conflict and civil unrest. September 9, 2020.
  28. Malik SM, Awan H, Khan N. Mapping vulnerability to climate change and its repercussions on human health in Pakistan. Globalization and Health. 2012;8(31). doi:10.1186/1744-8603-8-31
  29. Close RM, Pearson C, Cohn J. Vaccine-preventable disease and the under-utilization of immunizations in complex humanitarian emergencies. Vaccine. 2016;34(39):4649-4655. doi:10.1016/j.vaccine.2016.08.025
  30. World Health Organization. 18 million doses of first-ever malaria vaccine allocated to 12 African countries for 2023–2025: Gavi, WHO and UNICEF. 5 July 2023. https://www.who.int/news/item/05-07-2023-18-million-doses-of-first-ever-malaria-vaccine-allocated-to-12-african-countries-for-2023-2025–gavi–who-and-unicef
  31. Gavi, the Vaccine Alliance. Gavi outlines plans to build sustainable supply of malaria vaccines. 25 April 2023. https://www.gavi.org/news/media-room/gavi-outlines-plans-build-sustainable-supply-malaria-vaccines
  32. Gavi, the Vaccine Alliance. Global vaccine alliance outlines path to sustainable cholera vaccine supply. 22 May 2023. https://www.gavi.org/news/media-room/global-vaccine-alliance-outlines-path-sustainable-cholera-vaccine-supply

Vaccines are Key in Combating Antimicrobial Resistance (AMR)

Antimicrobial resistance (AMR) is a growing threat to the health of children worldwide. New evidence shows how vaccines are one promising way to combat the global spread of AMR. New research on typhoid conjugate vaccines (TCV) shows how immunization can protect children, families, and communities against the emergence of dangerously resistant superbugs.

Key Messages

  • WHO has declared that AMR is one of the top 10 global public health threats facing humanity.
  • With the identification of increasingly treatment-resistant typhoid strains, we are dangerously close to running out of options for oral antibiotic treatments.
  • Vaccines contribute to the battle against antimicrobial resistance (AMR) by preventing infections and by reducing the use of antibiotics.

Antimicrobial resistance (AMR) is one of the most urgent threats currently facing global health. Antimicrobials are medicines used to prevent and treat infections in humans, animals and plants and include antibiotics, antivirals, antifungals and antiparasitics. AMR occurs when bacteria, viruses, fungi, and parasites evolve over time and no longer respond to antimicrobial medicines. When pathogens become drug resistant, antibiotics and other antimicrobial medicines become ineffective and infections become increasingly difficult or impossible to treat leading to more severe illness and risk of death.

Vaccines already save millions of lives every year by preventing infectious diseases like pneumonia and diarrhea. However, new research provides evidence that vaccines are an important tool in preventing the spread of AMR. For World Antimicrobial Awareness Week (WAAW)(18-24 November) the VoICE team is highlighting the important role of vaccines in saving lives and combating antimicrobial resistance.

According to a 2019 UNICEF report, “The emergence and spread of AMR is occurring at an alarming rate with current estimates indicating that at least 700,000 people die worldwide each year due to drug-resistant infections, which is expected to rise to 10 million deaths globally by 2050.”

AMR is a Major Threat to Child Survival

“Vaccines are among the most effective tools to prevent infections, and they have the potential to make a major contribution to the control and prevention of AMR.” – World Health Organization, 2020

AMR is a leading cause of death around the world, with the highest burdens in low-resource settings. A Lancet analysis of the health impacts of AMR across 200 countries and territories found that AMR was directly responsible for an estimated 1.27 million deaths globally in 2019. For comparison, HIV/AIDS and malaria were estimated to have caused 860,000 and 640,000 deaths, respectively, in 2019. The highest rates of AMR burden occur in sub-Saharan Africa. Children living in low-resource settings with limited access to health and immunization services face some of the greatest risks of exposure to AMR.

While AMR poses a threat to people of all ages, children are particularly vulnerable to AMR infections as their immune systems are not fully developed.

Global AMR Deaths Prevented, 2019 graph

How #VaccinesWork to Counter the AMR Threat

How can vaccines combat the growing threat of “superbugs”? Vaccines against illnesses like typhoid, pneumonia, and diarrhea limit the spread of antimicrobial resistance through two main mechanisms:

  1. Vaccines lower the overall burden of infection, leading to a reduction in the transmission of resistant and susceptible pathogens.
  2. When children are vaccinated there are fewer infections, leading to less need for antibiotic medications. This reduces the selection pressure for pathogens to become resistant to antibiotics.
AMR Vaccine Prevention

A Vaccine Success Story Against XDR Typhoid

The Salmonella Typhi (S. Typhi) bacterium causes typhoid, an illness that kills between 128,000 and 161,000 people every year and sickens an another 11–20 million people.

Typhoid fever can be treated with antibiotics, however, an increasing resistance to antibiotics is making treatment for typhoid more difficult. Drug-resistant typhoid is an increasing threat for some countries, including Pakistan. Extensively drug-resistant (XDR) typhoid is resistant to five of the six available oral antibiotics, making these infections much more difficult and costly to treat.

An outbreak caused by an XDR strain of Salmonella Typhi was identified in Pakistan in 2016; within 4 years of its detection, XDR Salmonella Typhi constituted >80% of the entire Salmonella Typhi population in Pakistan, and it has since been detected in at least 10 countries.

2021 study of typhoid conjugate vaccine (TCV) immunization for children in Pakistan found that typhoid vaccines can be highly effective against drug-resistant typhoid.

  • TCV was 95% effective against culture-confirmed typhoid infection.
  • TCV was 97% effective against XDR typhoid strains.
  • TCV was 98% effective against non-XDR typhoid strains.

According to the Coalition Against Typhoid these findings also show “…that TCV is highly effective against XDR typhoid, demonstrating its potential to protect children against even the most difficult-to-treat typhoid cases.”

AMR Typhoid Prevention

The VIEW-hub website provides maps and downloadable data on current typhoid vaccine introductions.


Atkins, Katherine E, Erin I Lafferty, Sarah R Deeny, Nicholas G Davies, Julie V Robotham, and Mark Jit. “Use of Mathematical Modelling to Assess the Impact of Vaccines on Antibiotic Resistance.” The Lancet Infectious Diseases 18, no. 6 (June 2018): e204–13. https://doi.org/10.1016/S1473-3099(17)30478-4.

Gottberg, Anne von, Linda de Gouveia, Stefano Tempia, Vanessa Quan, Susan Meiring, Claire von Mollendorf, Shabir A. Madhi, et al. “Effects of Vaccination on Invasive Pneumococcal Disease in South Africa.” New England Journal of Medicine 371, no. 20 (November 13, 2014): 1889–99. https://doi.org/10.1056/NEJMoa1401914.

Jakab, Zsuzsanna. “Children’s Immature Immune Systems Threatened by Increasing ‘Superbugs,’” November 20, 2020. https://www.who.int/news-room/commentaries/detail/children-s-immature-immune-systems-threatened-by-increasing-superbugs.

Oxford GBD Group. “Antibiotic Resistance Caused More Than 1.2M Deaths in 2019, According to Landmark GRAM Study,” January 20, 2022. https://www.bdi.ox.ac.uk/oxfordgbdgroup/blog/antibiotic-resistance-caused-more-than-1-2m-deaths-in-2019-according-to-landmark-gram-study.

Qamar, Dr Farah Naz, Aga Khan University, and Pakistan. “Typhoid Conjugate Vaccine Is Effective against Drug-Resistant Typhoid.” Take on Typhoid, September 9, 2021. https://www.coalitionagainsttyphoid.org/typhoid-conjugate-vaccine-is-effective-against-drug-resistant-typhoid/.

Saha, Samir K, Nazifa Tabassum, and Senjuti Saha. “Typhoid Conjugate Vaccine: An Urgent Tool to Combat Typhoid and Tackle Antimicrobial Resistance.” The Journal of Infectious Diseases 224, no. Supplement_7 (December 20, 2021): S788–91. https://doi.org/10.1093/infdis/jiab443.

UNICEF. “Time Is Running Out: A Technical Note on Antimicrobial Resistance,” November 2019. https://www.unicef.org/documents/time-running-out.

Vekemans, Johan, Mateusz Hasso-Agopsowicz, Gagandeep Kang, William P. Hausdorff, Anthony Fiore, Elizabeth Tayler, Elizabeth J. Klemm, et al. “Leveraging Vaccines to Reduce Antibiotic Use and Prevent Antimicrobial Resistance: A World Health Organization Action Framework.” Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America 73, no. 4 (August 16, 2021): e1011–17. https://doi.org/10.1093/cid/ciab062.

Possibilities: The Far-Reaching Benefits of Immunization

Nurse preparing Immunization

The story of immunization is often headlined with the remarkable health benefits—millions of lives saved, and illnesses and hospitalizations prevented. But the true impact of vaccination is even more far-reaching, touching many areas of people’s lives from supporting early childhood growth and development to improving educational outcomes and productivity, promoting economic stability, and helping to address equity gaps: It’s seemingly impossible to undersell the importance of vaccination.

This World Immunization Week, the VoICE editors highlight some of the broader benefits of immunization—not only helping to prevent illness and save lives, but also promoting healthy development, productivity, economic stability, and equity for all.

Key Messages

  1. Only looking at the direct impact of vaccination on morbidity and mortality grossly underestimates the wider value of vaccination on overall health and development
  2. Several studies show that immunization has the potential to increase productivity by averting preventable illness
  3. Vaccines are associated with improved cognitive ability, education, and healthy physical development – which translates into increased economic productivity
  4. Vaccine-preventable diseases disproportionately affect the poorest children and families, but immunization can be a cost-effective tool to improve equity across geographies, gender, and marginalized populations

Preventing Pandemics Supports Economic Stability

The global health community is now facing an unprecedented challenge in the COVID-19 pandemic. As countries across the world attempt to slow the virus’s spread, this event has become a potent reminder of the vital importance of vaccination; we are seeing today just how much an infectious disease outbreak can ravage both national and global economies. Vaccines are important tools to help avert potentially catastrophic health costs that arise from preventable infectious disease outbreaks. Several studies have found that vaccines can bring additional stability to national economies by preventing the high costs incurred by illnesses.

  • 2009 study in Africa found an economic loss of US $43-72 million resulting from the 110,837 cases of cholera reported in 20071.
  • Researchers modeling the costs of potential pandemic influenza in the UK estimated costs of illness between £8.4 and £72.3 billion depending on the severity of the fatality rate, and even larger still for an extreme pandemic. In such a scenario, vaccination could limit the overall economic impact of pandemics2.

Vaccines Help Promote Productivity

 Productivity—the measure of output by a working individual or a population—is an important determinant of standard of living. By preventing illness, vaccination can help promote productivity by supporting healthy cognitive development and success in school, ultimately helping children achieve their full potential across the lifespan.

  • 2019 longitudinal study followed almost 6,000 children in India, Ethiopia, and Vietnam throughout childhood, finding that those vaccinated against measles scored better on cognitive tests of language development, math, and reading compared to children who did not receive measles vaccines3.
  • In a 2011 study in the Philippines, children vaccinated against six diseases performed significantly better on verbal reasoning, math and language tests than unvaccinated children4.
  • Vaccine-preventable diseases lead to both work and school absenteeism, which can negatively impact productivity and cause a substantial economic burden. A Norwegian study found that children hospitalized with rotavirus were absent from daycare for 6.3 days, on average, and 73% of their parents missed work5.

Vaccines Support Healthy Child Growth and Development

Some vaccine-preventable diseases can delay or interrupt normal growth and development in early childhood, leading to long-lasting damage that can adversely impact children for the rest of their lives. Persistent or recurrent infections in early life can lead to poor growth and stunting, which in turn can adversely affect adult health, cognitive capacity, and economic productivity.

  • Childhood vaccination programs can be a tool for mitigating undernutrition in developing countries. Children enrolled in Universal Immunization Programs observe improvements in terms of age-appropriate height and weight as per results of a study focused on 4-year-old children in India. On average, height and weight deficits were reduced by 22-25% and 15% respectively6.
  • study in Kenya revealed that polio, BCG, DPT and measles immunization had protective effects with respect to stunting in children. In children under the age of 2 years, children immunized with polio, BCG, DPT, and measles vaccines were 27% less likely to experience stunting compared to unimmunized children7.
  • A 2013 study conducted in several developing countries found that children with moderate-to-severe diarrhea grew significantly less in length in the two months following an episode of illness compared to age- and gender-matched controls8.
  • Modeling of data from India’s 2005-2006 National Family Health Survey indicated that vaccinations against DPT, polio, and measles were significant positive predictors of a child’s height, weight, and hemoglobin concentration. Such indicators, in turn, influence children’s cognitive development and hence the future supply of skilled labor that is critical for economic growth9.

Tackling Immunization Inequities Can Have Substantial Benefits

While huge progress has been made in introducing and scaling up access to important vaccines, we still have a long way to go. There is significant evidence of inequities in vaccine coverage that exists between and within countries, as well as between and within different populations. In Gavi-supported countries, there are still an estimated 10.4 million “zero-dose children” who have not received any doses of DTP-containing vaccine.

  • Results of a 2019 study in Kenya found that immunization outreach for remote or hard-to-reach populations can still be highly cost-effective. The study found that failure to vaccinate hard-to-reach children against measles would result in more than 1,400 measles cases, 257 deaths, and cost nearly U.S. $10 million over the course of 4 years, mainly due to productivity losses from caretakers missing work10.
  • 2018 study found that children of poor labor migrants living in Delhi, India are much less likely to be fully vaccinated than the general population and thus are at greater risk of vaccine-preventable diseases. Only 31% – 53% of children from migrant families were fully immunized (against 7 diseases) by 12 months of age, compared to 72% in the overall population of Delhi — with recent migrants having the lowest rates11.
  • Researchers looking at vaccination coverage in 45 low- and middle-income countries found that maternal education is a strong predictor of vaccine coverage. Children of the least educated mothers are 55% less likely to have received measles-containing vaccine and three doses of DTP vaccine than children of the most educated mothers12.

The evidence shows that vaccines offer cross-cutting benefits for individuals, families, communities, and truly everyone across the globe. Cross-disciplinary research from many global health perspectives demonstrates that vaccines as a versatile, impactful tool that does so much more than just preventing millions of deaths and illness every year: Vaccines benefit global economies, boost productivity, and help close gaps in equity.

As we respond to COVID-19, the reality that infectious disease outbreaks anywhere in the world can quickly become a threat anywhere further highlights the importance of investment in vaccination as a part of strong, resilient health systems. As countries across the world grapple with containing the COVID-19 outbreak, we must also work together to ensure that the world’s most vulnerable children don’t miss out on the vaccines that prevent devastating illnesses like measles, polio, diarrhea, and pneumonia. In the face of this current challenge, it’s essential that we work together to protect essential health services like immunization to ensure that all people have a shot at living a healthy life protected from preventable disease.

Visit the VoICE World Immunization Week 2020 Social Media Toolkit for messaging and images to promote the broad benefits of vaccines. The toolkit is also available on the official World Immunization Week 2020 website.


  1. Kirigia, J.M., Gambo, L.G., Yolouide, A., et al 2009. Economic burden of cholera in the WHO African Region. BMC International Health and Human Rights. 9(8). doi: 10.1186/1472-698X-9-8
  2. Smith, R.D., Keogh-Brown, M.R., Barnett, T., et al 2009. The economy-wide impact of pandemic influenza on the UK: a computable general equilibrium modeling experiment. BMJ. 339. https://doi.org/10.1136/bmj.b4571
  3. Nandi A, Shet A, Behrman JR, et al. 2019. Anthropometric, cognitive, and schooling benefits of measles vaccination: Longitudinal cohort analysis in Ethiopia, India, and Vietnam. Vaccine. 37. https://doi.org/10.1016/j.vaccine.2019.06.025
  4. Bloom, D. E., Canning, D., & Shenoy, E. S. (2011). The effect of vaccination on children’s physical and cognitive development in the Philippines. Applied Economics, 44(21), 2777-2783. https://doi.org/10.1080/00036846.2011.566203
  5. Edwards CH, Bekkewold T, Flem E. 2017. Lost workdays and healthcare use before and after hospital visits due to rotavirus and other gastroenteritis among young children in Norway. Vaccine. 35. https://doi.org/10.1016/j.vaccine.2017.05.037
  6. Anekwe, T.D., Kumar, S. 2012. The effect of a vaccination program on child anthropometry: Evidence from India’s Universal Immunization Program. Journal of Public Health. 34(4). https://doi.org/10.1093/pubmed/fds032
  7. Gewa, C.A. and Yandell, N. 2011. Undernutrition among Kenyan children: contribution of child, maternal and household factors. Public Health Nutrition. 15(6). https://doi.org/10.1017/S136898001100245X
  8. Kotloff, K.L., Nataro, J.P., Blackwelder, W.C., et al 2013. Burden and aetiology of diarrhoeal disease in infants and young children in developing countries (the Global Enteric Multicenter Study, GEMS): a prospective, case-control study. Lancet. 382(9888). https://doi.org/10.1016/S0140-6736(13)60844-2
  9. Bhargava, A., Guntupalli, A.M., Lokshin, M. 2011. Health Care Utilization, socioeconomic factors and child health in India. Journal of Biosocial Sciences. 43(6). https://doi.org/10.1017/S0021932011000241
  10. Lee BY, Brown ST, Haidari LA et al. 2019. Economic value of vaccinating geographically hard-to-reach populations with measles vaccine: a modeling application in Kenya. Vaccine. 37(17). https://doi.org/10.1016/j.vaccine.2019.03.007
  11. Kusuma YS, Kaushal S, Sundari AB, et al. 2018. Access to childhood immunization services and its determinants among recent and settled migrants in Delhi, India. Public Health. 158. https://doi.org/10.1016/j.puhe.2018.03.006
  12. Arsenault, C., Harper, S., Nandi, A., et al. 2017. Monitoring equity in vaccination coverage: A systematic analysis of demographic and health surveys from 45 Gavi-supported countries. Vaccine. 5(6). https://doi.org/10.1016/j.vaccine.2016.12.041

World Immunization Week 2020 Social Media Toolkit

VoIce banner for World Immunization Week 2020

World Immunization Week 2020 (April 24-30) is an opportunity for immunization advocates across the world to promote the value of vaccines for protecting people of all ages against preventable diseases. Our VoICE social media toolkit provides messaging on the vital role that vaccines play in global health. Beyond saving millions of lives every year #VaccinesWork For All by strengthening our health care systems, protecting global health security, shrinking equity gaps, and more.

Join us in promoting the message that #VaccinesWork For All by sharing the evidence on the broad benefits of immunization!

VoICE Social Media Toolkit for World Immunization Week 2020

Download the VoICE World Immunization Week 2020 Toolkit for a series of social media messages and shareable images that highlight key evidence on the value of vaccines! Messaging covers the six main topics of the VoICE Compendium: Health, Education, Economics, Equity, Health Systems and Integration, and Global Issues.

The toolkit is also available as a downloadable PDF and all images can be easily copied or saved directly from this page.

Welcome to WIW 2020!

Immunization saves millions of lives every year. Yet, there are still nearly 20 million children worldwide who are not getting the vaccines they need.

We have it in our power to close this gap!

Welcome to World Immunization Week banner


#DYK those with HIV, cancer, and weakened immune systems benefit from immunization of others through herd immunity?


Herd Effects Children banner

#VaccinesWork for all by protecting people around us, especially those who are vulnerable like new babies, older adults, and people who are seriously ill.


Herd Effects All Ages banner 2

Malnourished kids suffer the most from pneumonia, diarrhea and other vaccine-preventable infections.

It’s time to level the playing field!


Undernutrition cycle


#DYK that immunization is linked to improved education and cognitive outcomes? Immunized children stay healthier so they miss less school and attain higher school grades.




Vaccines don’t just save lives; they keep the world’s most vulnerable people out of poverty. A 2018 @Health_Affairs study found the poorest households receive the most benefit from increased access to vaccines.


Policy Poverty Quote

Studies show that vaccines can help stop poverty in addition to saving lives. Read the latest research on the economic benefits of vaccines.

#VaccinesWork for All


Prevent Poverty banner


13.5 million children around the world still can’t access vaccines – these children are often the most vulnerable to disease and health disparities. We have it in our power to close this gap!

Leaving no child behind means ensuring the most marginalized – those touched by conflict or forced from their homes – have access to lifesaving #vaccines.


Vaccines are a tool for reducing gender, geographic, and sociocultural inequity – find the latest evidence on immunization and equity on VoICE:




Immunization For Equity


Immunization can decrease hospital admissions, thus alleviating pressure on overburdened health systems, freeing up needed medical resources.


In Kenya, rates of pneumonia hospitalizations in children <5 dropped by 27% after 4 years of PCV10. #VaccinesWork for All to reduce hospital admissions and free up more resources to treat and prevent other illnesses.



Between 2005-2014 nearly 400 infectious disease outbreaks (excluding measles) were reported to the @WHO, threatening the health security of the entire world.

View @Voice_Evidence’s feature issue on #outbreaks to learn more: http://bit.ly/voice_outbreaks

Immunization Outbreaks banner

2019 saw a record for measles outbreaks – more than 140,000 lives were lost, mostly children.

Measles is so contagious that the exposure of a single person without immunity to the virus can spark an outbreak that quickly burns through whole communities.


Vaccine-preventable Outbreaks: Becoming All Too Common and Costly

Infographic of words related to outbreak

From Abuja to Atlanta, recent infectious disease outbreaks have all too commonly captured the regular news headlines. In this Featured Issue on vaccine-preventable disease outbreaks, the VoICE team goes past the headline, down to the fine print. We bring you an evidence-backed overview of vaccine-preventable infectious disease outbreaks worldwide, with a special focus on the circumstances that increase the likelihood of an outbreak, the less-obvious health and economic consequences, and a “top five” list for outbreak prevention and preparedness.

A selection of VoICE evidence in this issue

Paniz-Mondolfi AE, Tami A, Grillet ME et al. 2019. Resurgence of vaccine-preventable diseases in Venezuela as a regional public health threat in the Americas. Emerging Infectious Diseases. 25(4).

Suijkerbuijk AWM, Wondenberg T, Hahne SJM et al. 2015. Economic costs of measles outbreak in the Netherlands, 2013-2014. Emerging Infectious Diseases. 21(11).

Culver A, Rochat R, Cookson S 2017. Public health implications of complex emergencies and natural disasters. Conflict and health. 11(1).

Hammer CC, Brainard J, Hunter PR 2018. Risk factors and risk factor cascades for communicable disease outbreaks in complex humanitarian emergencies: a qualitative systematic review. BMJ Global Health. 3.

Calugar A, Ortega-Sanchez I, Tiwari T et al. 2006. Nosocomial pertussis: Costs of an outbreak and benefits of vaccinating health care workers. CID. 42.

Coltart CE, Johnson AM, Whitty CJ 2015. Role of healthcare workers in early epidemic spread of Ebola: policy implications of prophylactic compared to reactive vaccination policy in outbreak prevention and control. BMC Medicine. 13(271).

Huber C, Finelli L, Stevens W 2018. The economic and social burden of the 2014 Ebola outbreak in West Africa. JID. 22(5).

Takahashi S, Metcalf JE, Ferrari MJ et al. 2015. Reduced vaccination and the risk of measles and other childhood infections post-Ebola. Science. 347(6227).

Dayan GH, Ortega-Sanchez IR, LeBaron CW et al. 2005. The cost of containing one case of measles: the economic impact on the public health infrastructure — Iowa, 2004. Pediatrics. 116(1).

Constenla D., Carvalho A., Guzman NA. 2015. Economic impact of meningococcal outbreaks in Brazil and Colombia. Open Forum Infectious Diseases. 2(4).

Colombini A, Badolo O, Gessner BD et al. 2011. Cost and impact of meningitis epidemics for the public health system in Burkina Faso. Vaccine. 29.

Pike J, Tippins A, Nyaku M et al. 2017. Cost of a measles outbreak in a remote island economy: 2014 Federated States of Micronesia measles outbreak. Vaccine. 35(43).

Bambery Z, Cassell CH, Bennell RE et al. 2018. Impact of hypothetical infectious disease outbreak in US exports and export-based jobs. Health Security. 16.

Hagan JE, Greiner A, Luvsanshavar UO et al. 2017. Use of diagonal approach of health system strengthening and measles elimination after a large nationwide outbreak in Mongolia. Emerging Infectious Diseases. 23.

World Health Organization 2017. Weekly epidemiological record, Cholera vaccines: WHO position paper – August 2017. WHO Weekly epidemiological record. 92(34).

Jonas, O., Katz, R., Yansen, S., et al. 2018. Call for independent monitoring of disease outbreak preparedness. BMJ. 361.

Key Messages

  1. Infectious disease outbreaks can happen anywhere and have significant, and often hidden, social, health and economic repercussions.
  2. A large proportion of recent infectious disease outbreaks are of vaccine-preventable diseases.
  3. The likelihood or severity of an outbreak is increased by factors such as low vaccination coverage, crowding, poor sanitation, malnutrition, and human mobility.
  4. Outbreak prevention and preparedness needs to be systematically integrated into health systems and specific areas must urgently be strengthened to include immunized healthcare workers, streamlined health communications, and ready surveillance systems.


Disease outbreaks happen in nearly every corner of the globe – from the remote Amazon to Amsterdam. An analysis of a World Health Organization (WHO) epidemics database found that from 2005-2014, nearly 400 outbreaks of infectious disease (not including measles) were reported to the WHO. Nearly 40% of these outbreaks were due to vaccine-preventable diseases (VPDs) – with yellow fever, polio, meningococcal disease and cholera accounting for 9/10  of the outbreaks due to VPDs.  The proportion of outbreaks caused by VPDs was as high as 70% in the African region. The ubiquity of disease outbreaks globally speaks to the range of complex factors that contribute to outbreaks of various infectious diseases, but there are some combinations of factors that can easily ignite an outbreak of epidemic proportions.

Outbreak, epidemic, or pandemic?

Outbreak Highlight Box-Outbreak Epidemic Pandemic

A Fire Waiting to Happen:

Circumstances that increase the risk of outbreaks

There are a triad of elements that influence the likelihood and severity of an infectious disease outbreak. These include factors related to:

  1. The Pathogen – aspects of the disease agent itself (virus or bacteria), such as how it is transmitted from person to person, how contagious it is, the incubation period before symptoms appear, how severe the infection may be and how likely it is to result in death.
  2. The Population – factors affecting the state of health of the population at risk, including the proportion vaccinated, malnourished or living in sub-optimal conditions such as overcrowding, and how people move on small or large spatial scales.
  3. The Environment – generally refers to environmental factors that affect the spread of disease such as access to clean water and sanitation, access to health care, social norms and cultural practices – for example in the case of Ebola where traditional burial practices bring people into contact with infected bodily fluids which transmit the virus.

Figure 1: Pathogen, population, and environmental factors can ignite an outbreak of infectious disease.


An outbreak can ignite when sparked by only a handful of the factors described above, such as in the case of measles or pertussis – two highly contagious pathogens which can rapidly take advantage of gaps in vaccine coverage. In other circumstances, parts of all three elements – pathogen, population and environment – are present and create the perfect conditions to kindle an outbreak.

Cracks in the immunization firewall

A high firewall of immunization coverage with very very few gaps is required to protect populations from outbreaks of highly transmissible and contagious infections, such as measles or pertussis, which have the potential to spread rapidly and far. An infection like measles is so contagious that almost all susceptible people who are exposed will become infected meaning that about 95% of a community needs to be protected to stop measles virus transmission. Add to that the fact that contagiousness occurs before the telltale rash (and very often before anyone knows what is causing the illness), and you can see how just those two pathogen-related factors cause some outbreaks to explode. In a community with lower than 95% vaccine coverage, the exposure of a single person without immunity to the virus is the single spark that is needed to start an outbreak that quickly burns through a community of people who have little or no immunity. The connection between measles and low vaccination coverage is so strong that some researchers describe measles outbreaks as being a “canary in a coalmine” that brings to light programmatic weaknesses in immunization coverage in places where data on vaccination coverage is thin or unreliable.

Figure 2: Factors contributing to measles outbreaks.

The firewall for a disease like Ebola must be just as strong but for different reasons. Ebola is not very contagious when compared to other infections, but has an exceedingly high risk of death – up to 70% with some strains. (An animated visualization from the Washington Post of the relative contagiousness and mortality risk of different diseases.) When and exactly where the disease will appear is impossible to predict (see “The case of Ebola, a zoonotic infection”, below) and a vaccine against the disease has not yet been approved. For these reasons, outbreak control measures for Ebola, including significant efforts to find people who have been exposed, must be swift and widespread. An experimental vaccine for Ebola is being used in a “ring” vaccination strategy to vaccinate everyone who has come in contact with someone who has the disease, and has proven to be nearly 100% effective in preventing infection, if administered soon enough after exposure. Gaps in this vaccination ring mean the deadly disease has the potential to continue spreading.

Complex emergencies

Global socio-political events, including armed conflicts and other complex humanitarian emergencies, can result in a highly flammable set of circumstances – a “box of matches” containing nearly every population and environmental factor, which can easily spark a significant outbreak. In a study of the overlap between complex humanitarian emergencies and disease outbreaks, researchers found that more than 40% of complex emergencies that occurred between 2005-2014 were associated with an outbreak of infectious disease, with a high likelihood that the outbreak was vaccine-preventable.

The mass migration of people that often results from complex humanitarian emergencies can set off a “risk factor cascade”, that includes decreasing vaccination coverage, undernourishment, overcrowding, and poor sanitation, dramatically increasing the risk of an outbreak with each added cascade factor.

When environmental conditions are poor and pathogen-related factors are significant, only a tiny spark is required to ignite an outbreak, as is often the case with cholera. The bacteria that causes cholera (Vibrio cholera), a highly contagious diarrheal disease, can be quickly passed to large numbers of people through contaminated water in crowded and poorly-resourced settings such as urban slums or refugee camps that have poor access to clean water and sanitation. Rainfall further spreads the contaminated water, sustaining the outbreak. Population factors, such as undernutrition further worsen the disease.  Undernourished people are at greater risk of severe cholera infections and of dying from the infection.

Figure 3: Factors contributing to cholera outbreaks.

Outbreaks, Figure 3, Cholera

The case of Ebola, a zoonotic infection

Most vaccine-preventable outbreaks are due to pathogens which circulate constantly among humans, causing spikes in disease when population and environmental conditions allow. Ebola, however, is a zoonotic infection, meaning that the normal reservoir for the pathogen is among animals, most likely bats. Ebola outbreaks among humans are triggered when people come into contact with infected animals (such as through the consumption of bush meat from infected primates), become ill and then pass the virus to other humans where it spreads until it can be contained.

Predicting when and where the virus will strike and spark an outbreak is thus very difficult, which significantly adds to the challenges of planning for, controlling and mitigating the impact of outbreaks. Ebola is one of several diseases of zoonotic origins  that has the potential to ignite a global pandemic, according to USAID.

The Repercussions of Vaccine-Preventable Outbreaks

While outbreaks of measles and Ebola have been widely covered in the news media, a less visible topic has been the significant – and sometimes long-term – health and economic repercussions that come along with outbreaks of these and other diseases.

Repercussions on health systems

By definition, an outbreak is the occurrence of disease in a population that rises above expected levels. Although contingency plans may be in place for dealing with an outbreak, health staff, funding, medical supplies and other resources are often diverted to outbreak control, weakening the provision of other health services. In one example from Burkina Faso in 2007, meningitis epidemics disrupted health services at every level. Impact on all people seeking healthcare included longer wait times to be seen, increased time for lab test results, higher stress among caregivers and an increase in the number of misdiagnoses by overtaxed health care workers (HCWs).

Repercussions for healthcare workers

The burden on HCWs, in fact, extends beyond exhaustion and the mental toll of working in outbreak conditions. Health workers themselves are at significant risk of becoming victims of an infectious disease outbreak and passing on the infection to others, in particular before the infectious agent has been identified. HCWs can account for a substantial proportion of disease cases. A recent study using data from historical outbreaks of Ebola in Guinea and Nigeria, found that (had a fully effective vaccine been available at the time of those outbreaks) prophylactically vaccinating healthcare workers would have decreased the size of the Ebola epidemics in those countries by 60-80%. In the US, researchers estimated that ensuring full vaccination of healthcare workers would prevent more than 45% of exposures to pertussis that occur in healthcare settings. These are only two of many examples illustrating the disproportionate burden of disease cases among HCWs, all of which highlight critical gaps in vaccine coverage among people at significantly increased personal risk, and risk of infecting others. (For more on the WHO’s recommendations for immunizing health care workers.)

Repercussions of every kind: The Ebola firestorm

Outbreaks of exceptionally deadly infectious diseases such as Ebola can cause a cascade of events affecting every person and sector in a community and thus represent a firestorm of all the potential repercussions of an outbreak occurring at once. Huber et al described the devastating and far-reaching impact of the 2014 Ebola outbreak in West Africa, including more than half a million people experiencing food insecurity, school closures lasting more than 7 months, tens of thousands of children orphaned, a huge proportion of the health workforce killed by the disease, infant, maternal and child deaths from lack of skilled health workforce and a 97% reduction in surgical capacity, to name a few. A second study projected that the crippling of immunization programs resulting from the Ebola outbreak could double the number of people at risk for measles, ultimately killing nearly as many people as Ebola itself.

Ebola Treatment Center in Beni, Democratic Republic of the Congo’s North Kivu Province
At ALIMA’s (The Alliance for International Medical Action) Ebola Treatment Center in Beni, Democratic Republic of the Congo’s North Kivu Province, health workers care for patients infected with Ebola within ALIMA’s innovative biosecure emergency care unit – the CUBE.

Economic repercussions: costs of outbreaks

Adding to the secondary health and societal costs of infectious disease outbreaks are the actual monetary and economic impacts, which are significant even in a relatively small and quickly contained outbreak. The larger and longer an outbreak, the more significant its macroeconomic impacts on productivity, import & export losses, reduced tourism revenue and consumption.

From cholera to measles to Ebola, health economists have published several studies on the economic impact of outbreaks, covering direct costs of outbreak management to slowed national economic growth as a result of outbreaks. Direct costs to health systems include outbreak investigation costs such as personnel, supplies, travel expenses to find people exposed to infection and outbreak containment efforts including vaccination or prophylactic treatment costs for those exposed. Costs to individual families seeking treatment can be significant and have long-term economic consequences. Productivity losses and reduced consumption and revenue directly affect nations dealing with outbreaks, but shifts in imports and exports internationally can impact other nations economically, despite not being directly affected by the outbreak. Just some of the economic repercussions can be found in the cases below:

Outbreak Prevention and Preparedness

The prevention, mitigation and control of infectious disease outbreaks is becoming more urgent, while the number of emerging diseases increases, populations are more mobile and economies are stretched thin. Addressing infectious disease outbreaks must be a high political priority, requiring investments of both financial support and political will. But investments in what exactly?

It will come as no surprise that vaccination features prominently in our “TOP FIVE” list of investments that must be made to better prevent and prepare for outbreaks of infectious disease. What may be surprising is that financing, purchasing and delivering vaccines to the general population is only one of the necessary steps towards ensuring that the full potential of immunization can be realized in helping to prevent, mitigate and control outbreaks. Clear and actionable preparedness plans, robust health systems with increased access to health care, and significantly increased investments in disease surveillance and health communication round out our list.

Top Five Investments In Outbreak Prevention And Preparedness

1. Investment in health systems, including routine immunization

A country’s ability to prevent, detect and respond to outbreaks is tied to the strength and capacities of its health system overall. As such, a 2018 multi-stakeholder outbreak preparedness framework includes strengthening overall public health system capacity as the first of four pillars in the prevention of significant disease epidemics and pandemics.

National and subnational health systems supported by recommended levels of funding, high political priority and strategic planning processes that include the integration of emergency preparedness and everyday health systems operations are more resilient to emergencies such as disease outbreaks, and can recover more quickly. A 2016 WHO-led consultation with countries in the African region found that health systems and health security-related structures functioned independently from one another, but that strong support existed for the integration of emergency prevention and preparedness in broader health systems.

Given the high proportion of outbreaks due to vaccine-preventable infectious diseases, immunization has an especially important role to play in the prevention of disease outbreaks, and is thus critical for emergency prevention and preparedness.

2. Full immunization for health workers

High coverage of routine immunization is a critical firewall to prevent outbreaks from occurring, and vaccination of healthcare workers is especially critical to minimizing the spread of an emerging outbreak. Several studies have demonstrated the significant return on investment to be had by ensuring HCWs are fully immunized, given that HCWs often account for a disproportionately large number of disease cases. In the US study looking at prevention of the spread of pertussis referenced above, the financial return on vaccinating healthcare workers in hospitals was estimated to be nearly two and a half times the cost invested. A similar study of pertussis vaccine and HCWs in the Netherlands estimated the return on investment to be four times as great as the initial cost.

3. Actionable preparedness plan

Despite strong evidence that prevention and preparedness provide a sizeable return on investment, compared to the costs of an unchecked outbreak of disease, between 2016 and 2018 only one third of countries had assessed their own capacity to prevent, detect and control disease outbreaks.[1] That number has now risen to just under half, but nearly 80% of countries who have completed a preparedness assessment are wholly or partially unprepared for an outbreak of disease.[1] Experts argue that the cycle of panic and neglect in addressing disease outbreak readiness is a crisis of global proportions, and one which can only be broken by implementing and monitoring concrete preparedness plans.

4. Public health communications

Following recent global disease events like Ebola and SARS, which ignited global panic about the outbreaks and their impact, recognition has been increasing of the importance of consistent, clear and culturally sensitive communication with the public around health issues. Investment of money and time in this area, however, still lags behind the need. The WHO’s Outbreak Communication guidelines emphasize not only what needs to be done to communicate during an outbreak, but also the importance of building and maintaining trust in national and health authorities among all communities as a foundation for health communications and care seeking overall. Trust in an existing foundation of open, clear communication can help immunize against panic and increase compliance with measures intended to control and end outbreaks.

5. Infectious disease surveillance

The importance of disease surveillance, robust enough to detect outbreaks early, cannot be overstated, and yet, it is an area that is often poorly integrated in the broader public health system, and is chronically underfunded. Considered an essential public health capacity, investments in surveillance as it relates to outbreak detection and control are likely to have important benefits for other health priorities and diseases. For example, polio detection systems in the Americas were leveraged to better detect measles and rubella. Likewise, laboratory experience with measles and rubella surveillance led to the early detection and response to the H1N1 influenza virus in Mexico in 2009.

In summary, the specifics of the strategy for implementing each of these actions vary based on the type of outbreak. For example, the current vaccination strategy for Ebola includes finding and vaccinating all people who have come in contact with someone who has the disease (and all of those contacts’ contacts) to form a “ring” of immunity around disease cases. By contrast, measles and pertussis vaccines are recommended for all children worldwide during early childhood. Despite such differences in the specific approach needed, each of these five areas above are critical for mitigating the immediate impact and secondary repercussions of all future outbreaks.

[1] Jonas, Katz, et al. Call for independent monitoring of disease outbreak preparedness. BMJ. 2018;361:k2269 doi: 10.1136/bmj.k2269

Editorial Commentary

“We are witnessing an apparent increase in the magnitude and frequency of outbreaks due to vaccine-preventable diseases, as adroitly described in this VoICE Featured Issue. Such outbreaks are, by definition, preventable and thus a tragedy, resulting in pointless deaths, countless disabilities, loss of productivity, and economic costs. We must do better. We call on policy makers, community leaders, and the global public health community to improve surveillance systems to detect outbreaks as early as possible, improve vaccination coverage to ensure all children are appropriately immunized, and effectively communicate the benefits of vaccination so trust in public health is restored. We will face new infectious disease threats. We must control those diseases for which we already have safe and effective vaccines so we are best prepared to deal with the emerging ones.”

William Moss, MD, MPH
Interim Executive Director, International Vaccine Access Center

William Moss, MD, MPH is Interim Executive Director, at the Johns Hopkins Bloomberg School of Public Health’s, International Vaccine Access Center (IVAC), a pediatrician and infectious disease specialist who has dedicated the last three decades to improving the lives of children through better treatment and prevention of infectious disease. Dr. Moss has made significant contributions in many areas, including HIV, malaria, complex humanitarian emergencies and especially measles, for which he is a member of the World Health Organization’s expert Working Group on Measles and Rubella.