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.
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Conflict events can disrupt immunization programs and lead to attacks on health workers
This modeling study examined the impact of conflict events on disease control efforts during an Ebola outbreak in the Democratic Republic of the Congo. The model used a timeline of conflict events and an ethnographic appraisal of attacks on health care workers and treatment centers to estimate their impact on the epidemic trajectory of Ebola. Overall, the population-level effectiveness of vaccination was reduced by 43% due to disruptive conflict events. The researchers also found that declining incidence of Ebola was repeatedly reversed by conflict events. This framework can be extended to other diseases and regions experiencing conflict.
Wells CR, Pandey A, Ndeffo Mbah ML et al.. 2019. The exacerbation of Ebola outbreaks by conflict in the Democratic Republic of the Congo. Proceedings of the National Academy of Sciences. 116(48).
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).
Efforts to eradicate polio have also led to improved access to other vaccines
The expertise and assets gained through efforts to eradicate polio at least partially explain the improvement between 2013 and 2015 in vaccination coverage of DPT3 in six out of ten “focus” countries of the Polio Eradication Endgame strategic plan. This includes substantial increases in vaccination rates in India, Nigeria, and Ethiopia, which, combined, reduced the number of children not fully vaccinated with DPT by 2 million in 2 years.
van den Ent MMVX, Mallya A, Sandhu H et al.. 2017. Experiences and lessons from polio eradication in 10 focus countries of the polio endgame strategic plan. Journal of Infectious Diseases. 216(1).
Disease outbreaks can be associated with school closures, food insecurity, and health system disruptions
In a 2018 study, researchers describe the devastating and far-reaching impacts 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, and a huge proportion of the health workforce killed by the disease, leading to infant, maternal, and child deaths due to a lack of skilled health workers and a 97% reduction in surgical capacity.
Huber C, Finelli L, Stevens W. 2018. The economic and social burden of the 2014 Ebola outbreak in West Africa. JID. 22(5).
The impact of disease outbreaks on health systems and governments can cost billions of dollars
In a comprehensive accounting of the costs of the 2014 Ebola outbreak in West Africa, Huber et al. estimate the economic and social costs to have been US$53 billion, of which US$18.8 billion was attributed to non-Ebola deaths.
Huber C, Finelli L, Stevens W. 2018. The economic and social burden of the 2014 Ebola outbreak in West Africa. JID. 22(5).
Vaccinating all healthcare workers against Ebola could have dramatically reduced cases
Using data on the spread of Ebola from person to person during historical Ebola outbreaks to compare vaccination strategies, researchers found that prophylatically vaccinating all healthcare workers would have decreased the number of disease cases in the 2014 epidemics in Guinea and Nigeria by 60-80%.
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).
Children whose mothers have secondary education or higher are more likely to be fully immunized
Children of mothers with secondary education or higher were significantly more likely to be fully immunized than children of mothers with lower levels of educational attainment.
Acharya P., Kismul H., Mapatano, M.A., et al.. 2018. Individual- and Community-level Determinants of Child Immunization in the Democratic Republic of Congo: A Multilevel Analysis. PLOS One. 13(8).
Immunization coverage can vary greatly between regions within a country
Full immunization coverage, within the Democratic Republic of Congo, varies drastically by region. In the province with the lowest coverage, approximately 5% of children were fully immunized, while in the province with highest coverage, over 70% of children were fully immunized.
Acharya P., Kismul H., Mapatano, M.A., et al.. 2018. Individual- and Community-level Determinants of Child Immunization in the Democratic Republic of Congo: A Multilevel Analysis. PLOS One. 13(8).
Communities with better access to healthcare have higher rates of immunization coverage
Communities with higher rates of health services utilization, particularly institutional childbirth, were more likely to have higher immunization coverage rates. This data, from a study in the Democratic Republic of Congo, had an adjusted odds ratio of 2.36.
Acharya P., Kismul H., Mapatano, M.A., et al.. 2018. Individual- and Community-level Determinants of Child Immunization in the Democratic Republic of Congo: A Multilevel Analysis. PLOS One. 13(8).
Chronically malnourished children are less likely to receive proper vacccination dosage
In urban residents in the Democratic Republic of Congo, chronically malnourished children were less likely to have received two doses of measles-containing vaccine compared to healthy children.
Ashbaugh, H.R., Hoff, N.A., Doshi, R. H., et al.. 2018. Predictors of measles vaccination coverage among children 6–59 months of age in the Democratic Republic of the Congo. Vaccine. 36(4).