The Knowledge Hub

What is the Knowledge Hub?

Explore the VoICE Knowledge Hub—a searchable database featuring the latest peer-reviewed research on immunization benefits, especially in low- and middle-income countries. Browse the Knowledge Hub using a variety of different filters to find vaccine evidence based on country, region, topic, or disease. Click on a tag to find more evidence on a specific area, such as the return on investment of vaccines or impacts of infectious disease outbreaks.


Diseases & Vaccines


WHO Regions


Immunization Terms

Immunization programs have saved millions of lives, especially among children, and will continue to do so in the future

Increases in vaccine coverage and the introduction of new vaccines into LMICs have had a major impact in reducing mortality. Vaccination programs for ten selected pathogens will have averted an estimated 69 million deaths in 98 low- and middle-income countries between 2000 and 2030. Most of this impact has been concentrated in a reduction in mortality among children younger than 5 years (57% reduction), most notably from measles. These public health gains are predicted to increase in coming decades if progress in increasing vaccine coverage is sustained.

Li X, Mukandavire C, Cucunubá ZM et al.. 2021. Estimating the health impact of vaccination against ten pathogens in 98 low-income and middle-income countries from 2000 to 2030: a modelling study. The Lancet. 397(10272).

Globally, immunization has a high return on investment saving billions of dollars by preventing disability, health costs, and premature deaths

By preventing illness, disability, premature death, lost wages, and other costs, this modeling study found that vaccines against ten pathogens averted $828.5 billion of economic burden in 94 low- and middle-income countries between 2021 and 2030. Immunization programs provided a high return on investment (ROI), with projections for net benefits of vaccine programs estimated at $1,445.3 billion (using a cost-of-illness approach) and $3,371.5 billion (using a value-of-a-statistical-life approach) from 2011 to 2030. For every $1 invested in immunization, there was a return on investment of $20 using cost-of-illness and $52 using a value-of-a-statistical-life approach.

Sim SY, Watts E, Constenla D et al.. 2020. Return On Investment From Immunization Against 10 Pathogens In 94 Low- And Middle-Income Countries, 2011–30. Health Affairs. 39(8).

Reactive vaccination campaigns prevented a large measles outbreak, saving thousands of cases in a refugee camp

A large measles outbreak of 1,700 cases occurred in the Rohingya refugee population in Cox’s Bazar, Bangladesh in 2017. In response, two reactive vaccination campaigns delivered the measles and rubella (MR) vaccine to children aged 6 months to 15 years old. This modeling study found that these reactive vaccination campaigns rapidly curbed outbreak transmission, averting an estimated 77,000 measles cases in the refugee camp. This demonstrates that reactive vaccination campaigns can be highly effective in preventing large measles outbreaks in the context of refugee camps, even when prior vaccination rates are low.

Chin T, Buckee CO, Mahmud AS. 2020. Quantifying the success of measles vaccination campaigns in the Rohingya refugee camps. Epidemics. 30.

Immunization can reduce child mortality and enhance the immune system’s ability to fight against other diseases

This 2013 review summarizes data from several randomized trials in which measles and tuberculosis vaccines were associated with a substantial reduction in overall child mortality, which cannot be solely explained by prevention of the target disease. These studies suggest that in addition to disease-specific effects, some live vaccines may also provide “nonspecific effects” that enhance the immune system’s ability to protect against additional pathogens.

Benn CS, Netea MG, Selin LK et al.. 2013. A small jab – a big effect: Nonspecific immunomodulation by vaccines. Trends in Immunology. 34(9).

Mobile health teams in Afghanistan improved immunization coverage in remote and conflict-affected areas, benefiting mothers and children

In Afghanistan, delivering health services through sustained, scheduled mobile health teams in remote and conflict-affected villages improved coverage of maternal and child health interventions, including immunization. The proportion of children under 1 year receiving their first dose of measles vaccine was higher in districts that had received mobile health team services for at least the previous 3 years (73.8%) compared to control districts in the same province (57.3%). The researchers concluded that incorporating mobile clinics into health system infrastructure in a systematic way can effectively improve health for hard to reach mothers and children in remote and conflict-affected areas.

Edmond K, Yousufi K, Naziri M et al.. 2020. Mobile outreach health services for mothers and children in conflict-affected and remote areas: A population-based study from Afghanistan. Archives of Disease in Childhood. 105(1).

Investments in polio eradication in Africa improved overall immunization systems and increased coverage of routine vaccinations

A systematic review of 8 African countries that had wild polio virus transmission and significant polio eradication activities found evidence that the huge investments made in polio have strengthened capacity in almost all aspects of the overall immunization systems, especially in the areas of microplanning, service delivery, capacity-building (especially supportive supervision and on-the-job training), and program management. This led to substantial increases in coverage of other routine vaccinations – BCG, DPT, measles – in all 8 countries over a 25-year period (1989-2014), including a more than a 3-fold increase in DPT3 coverage in 2 countries and a more than a 2-fold increase in 3 other countries.

Anya BPM, Moturi E, Aschalew T et al.. 2016. Contribution of polio eradication initiative to strengthening routine immunization: lessons learnt in the WHO African region. Vaccine. 34(43).

Immunization campaigns against measles and rubella have improved routine immunization systems and disease prevention measures

A survey of 23 countries in all WHO regions found that activities to eliminate measles and rubella, including vaccination campaigns, have strengthened the countries’ overall routine immunization systems in a number of ways. These include microplanning that led to revised catchment populations and denominators for target-age children, expansion of cold chain systems that extended the reach of immunization, strengthening of surveillance and of outbreak preparedness and response for vaccine-preventable and other diseases.

Biellik RJ, Orenstein WA. 2018. Strengthening routine immunization through measles-rubella elimination. Vaccine. 36(37).

Immunization saves money by preventing complications and long-term health issues like hearing loss

An analysis of current measles vaccination program in the eastern Chinese province of Zhejiang (which provides 1 dose of measles-rubella vaccine at 8 months of age and 1 dose of MMR at 18 months) estimated that, for every dollar spent on immunization, the health system saves $6.06 in treatment costing, including the costs of treating complications and long-term sequelae, such as hearing loss.

Zeng Y, Luo M, Chen J et al.. 2019. An economic evaluation of the current measles vaccination program: a case study in Zhejiang Province, east China. Vaccine. 37(23).

Tetanus vaccination during pregnancy in India reduces delayed vaccination in children, especially for those born at home

In India, children whose mothers received tetanus vaccination during their pregnancy were 22-31% less likely to have delayed vaccination (depending on the vaccine) than children of unvaccinated mothers. Those born at home were nearly 3 times more likely to receive BCG vaccination late and 41% more likely to receive their first dose of DTP late than those born in a public health facility.

Choudhary TS, Reddy NS, Apte A et al.. 2019. Delayed vaccination and its predictors among children under 2 years in India: Insights from the national family survey-4. Vaccine. 37(17).

Children from the poorest households in India are more likely to have delayed vaccinations, increasing disease risk

Indian children in households from the lowest wealth quintile were 30-95% more likely to be delayed in their vaccinations than those from the wealthiest households [depending on the vaccine]. Delayed vaccination increases the window of susceptibility to vaccine preventable diseases and can lead to outbreaks.

Data in this analysis was from the National Family and Health Survey 4.

Choudhary TS, Reddy NS, Apte A et al.. 2019. Delayed vaccination and its predictors among children under 2 years in India: Insights from the national family survey-4. Vaccine. 37(17).