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

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).

Integrating vitamin A supplementation during vaccine campaigns increased coverage and effectiveness for both interventions

In an effort to reach children with vitamin A deficiency in the African countries of Angola, Chad, Cote d’Ivoire, and Togo, vitamin A supplementation was administered during Polio vaccine campaigns. This led to a minimum coverage of 80% for vitamin A and 84% for polio vaccine in all of the immunization campaigns. During the second year of vitamin A integration into the polio vaccination campaign, coverage exceeded 90% for both vitamin A and polio vaccination in all four countries.

Chebab, E.T., et al.. 2016. Experience of integrating vitamin A supplementation into polio campaigns in the African Region.. Vaccine. 34(43).

Pediatric pneumococcal or Hib meningitis surviviors had a higher likelihood for neuropsychological deficits

In a systematic literature review of studies in Africa, it was found that 25% of children who survived pneumococcal or Hib meningitis had neuropsychological deficits.

Ramakrishnan, M., Ulland, A.J., Steinhardt, L.C., et al. 2009. Sequelae due to bacterial meningitis among African children: a systematic literature review. BMC Medicine. 7(47).

Bacterial meningitis is associated with long-term neurophysiological impacts

A systematic literature review analyzing data from 21 African countries revealed that bacterial meningitis is associated with high case fatality and frequent neurophysiological sequelae. Pneumococcal and Hib meningitis contribute to one third of disease related mortality. They also cause clinically evident sequalae in 25% of survivors prior to hospital discharge. The three main causes of bacterial meningitis- Haemophilus influenzae type B; Streptococcus pneumoniae (pneumococcus) and Neisseria meningitidis (meningococcus) are vaccine preventable, routine use of conjugate vaccines have potential for significant health and economic benefits.

Neuropsychological sequelae includes hearing loss, vision loss, cognitive delay, speech/language disorder, behavioural problems, motor delays/impairment, and seizures.

Ramakrishnan, M., Ulland, A.J., Steinhardt, L.C., et al. 2009. Sequelae due to bacterial meningitis among African children: a systematic literature review. BMC Medicine. 7(47).