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).

Influenza vaccines reduce antibiotic use by preventing secondary infections and unnecessary prescriptions for respiratory illnesses

Vaccines against influenza reduce the use of antibiotics that drive drug resistance in bacteria in two ways. First, they prevent secondary bacterial infections caused by influenza, such as pneumonia and otitis media; in Ontario, Canada, the rate of prescribing for influenza-associated antibiotics declined around 64% after universal introduction of influenza vaccination compared to other Canadian provinces with more limited use of the vaccine. Second, they help prevent inappropriate antibiotic prescriptions for respiratory tract infections caused by influenza and other viruses, which account for half of all respiratory illnesses for which antibiotics are prescribed in the U.S.

Jansen KU, Knirsch C, Anderson AS. 2018. The role of vaccines in preventing bacterial antimicrobial resistance. Nature Medicine. 24(1).

China could save money by including the Hib vaccine in the national immunization program

If China — one of the few remaining countries in the world that haven’t introduced Hib vaccine in their national immunization program — decides to include the vaccine in their program, it could actually be cost saving; the vaccination costs would be less than the averted costs of illness from Hib meningitis and pneumonia, if a vaccine price matching UNICEF’s (US$2/dose) can be obtained. The vaccination will be cost-effective, but not cost saving, if the program pays the current market price in China of US$10 per dose.

Ning G, Yin Z, Li Y et al. 2018. Cost-effectiveness of the Haemophilus influenzae type b vaccine for infants in mainland China. Human Vaccines & Immunotherapeutics. 14(1).

The introduction of the Hib vaccine in Tamil Nadu led to a 79% decline in meningitis cases in children under two years

In a major children’s hospital in the Indian state of Tamil Nadu, meningitis cases caused by Haemophilus influenzae type b (Hib) in children under two years declined by 79% within two years of the introduction of Hib vaccine. This decline was greater than expected given a vaccination coverage of ~70% for one dose of the vaccine and much greater than expected with a 53% coverage rate for three doses. This suggests that the vaccine protected unvaccinated children through herd immunity.

Fitzwater SP, Ramachandran P, Kahn GD et al.. 2019. Impact of the introduction of the Haemophilus influenzae type b conjugate vaccine in an urban setting in southern India. Vaccine. 37(12).

Immunization can prevent medical debts and improverishment, particularly in the poorest populations

A study modeling the economic impact of 10 childhood immunizations in 41 low- and middle-income countries found that the bulk of poverty averted through vaccination occurs in poor populations. For most of the vaccines in the study, at least 40% of the poverty averted would occur in the poorest wealth quintile. Particularly for pneumonia, more than half of the two million deaths averted by pneumococcal and Hib vaccines would occur in the poorest 40% of the population.

Chang, A.Y., Riumallo-Herl, C., Perales, N.A., et al.. 2018. The equity impact vaccines may have on averting deaths and medical impoverishment in developing countries. Health Affairs. 37(2).

Vaccination can prevent over a million cases of poverty in low- and middle-income countries

Vaccines that can protect against pneumonia – Hib and S. pneumoniae vaccines – can together prevent over 1.25 million cases of poverty over 15 years, found researchers modeling the economic impact of immunization in 41 low- and middle-income countries.

Chang, A.Y., Riumallo-Herl, C., Perales, N.A., et al.. 2018. The equity impact vaccines may have on averting deaths and medical impoverishment in developing countries. Health Affairs. 37(2).

Vaccination can help prevent impoverishment, especially in low-income populations

In a study modeling the economic impact of immunization in 41 low- and middle-income countries, the authors estimate that 24 million cases of medical impoverishment would be averted through the use of vaccines administered from 2016-2030. The largest proportion of poverty cases averted would occur in the poorest 40% of these populations, demonstrating that vaccination can provide financial risk protection to the most economically vulnerable.

Chang, A.Y., Riumallo-Herl, C., Perales, N.A., et al.. 2018. The equity impact vaccines may have on averting deaths and medical impoverishment in developing countries. Health Affairs. 37(2).

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).