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.


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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).

Immunization can prevent costly meningitis outbreaks

Two meningococcal meningitis outbreaks in Brazil resulted in US$128,000 (9 cases, 2007) and US$34,000 (3 cases, 2011) in direct costs to the health system to investigate cases and manage the outbreak (including emergency vaccination). The investigation and response activities related to the 2011 outbreak alone cost $11,475 per case, and an additional $6,600 overall for supplemental disease surveillance activities.

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

Immunization can prevent costly outbreaks and save money for the healthcare system

A large meningococcal meningitis epidemic in Burkina Faso cost the health system an estimated US$7.1 million, representing nearly 2% of the country’s entire annual health budget.

In this study of a 2007 outbreak, 86% of the health system cost covered a reactive vaccination campaign using older polysaccharide vaccines. Routine vaccination with new, conjugate vaccines are expected to prevent or limit future outbreaks and thus reduce these costs.

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.

Meningitis epidemics in Burkina Faso caused major disruptions in healthcare services and increased misdiagnoses

Meningococcal meningitis epidemics in Burkina Faso “… disrupted all health services from national to operational levels,…” according to a 2011 study. Impacts included a shortage of available hospital beds and medicines, a reduction or delay in routine lab analyses for other diseases, longer wait times, and an increase in misdiagnoses by overtaxed health workers.

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.

Immunization can prevent costly meningitis outbreaks and protect households from financial burden and lost income

A 2006-07 meningococcal meningitis epidemic in Burkina Faso cost households an average of US$90 for each case of meningitis that occurred. These costs — representing nearly 2.5 months of the average per capita income for that year — included direct and indirect costs of treatment and lost income to caretakers.

Colombini A, Bationo F, Zongo S, et al.. 2009. Costs for households and community perception of meningitis outbreaks in Burkina Faso. Clinical Infectious Disease. 49(10).

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).

Vaccine-preventable diseases can leave children with life-long health issues, exacerbating family financial hardships

Among families participating in a study in Western Cape, South Africa, 35% of mothers who were previously employed stopped working to care for children who had survived tuberculosis meningitis resulting in permanent disabilities. 19% of families reported experiencing financial loss as a result of caring for these disabled children.

Krauss-Mars, A.H., and Lachman, P.I.. 1992. Social factors associated with tuberculosis meningitis. South African Medical Journal. 81(1).

Immunization can prevent severe long-term impacts of infections, including seizures and hearing loss

In The Gambia, 58% of children who survived pneumococcal meningitis had long lasting negative health outcomes. Half had major disabilities such as mental retardation, hearing loss, motor abnormalities, and seizures.

Goetghebuer, T., West, T.E., Wermenbol, V., et al. 2000. Outcome of meningitis caused by Streptococcus pneumoniae and Haemophilus influenzae type b in children in The Gambia. Tropical Medicine and International Health. 5(3).