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).

Vaccinating both boys and girls against HPV can eradicate cancer-causing types of the virus

A Swedish-Finnish study conducted between 2007-2014 found that vaccinating both girls and boys against HPV (a gender-neutral vaccination strategy) could lead to the eradication of the most common cancer-causing types of the virus through stronger herd immunity. The study randomized HPV vaccination interventions across 33 towns (gender neutral HPV, girls-only HPV, and a control non-HPV vaccination), including 80,000 adolescents between ages 12 and 15. Results of general HPV screening at the age of 19 showed that gender-neutral vaccination prevented HPV infections much more effectively than vaccinating girls only.

Vänskä S, Luostarinen T, Baussano I et al.. 2020. Vaccination with moderate coverage eradicates oncogenic human papillomaviruses if a gender-neutral strategy is applied. The Journal of Infectious Diseases. 222(6).

HPV vaccination rates in England are lower in areas with more migrant families and non-whites

Coverage rates of HPV vaccination in England, which is provided to 12-13 year old girls through a government-funded, school-based program, were significantly lower in areas with higher proportions of migrant families and non-whites than in areas that are predominantly native-born and white.

Jean S, Elshafei M, Buttenheim A. 2018. Social determinants of community-level human papillomavirus vaccination coverage in a school-based vaccination programme. Sexually Transmitted Infections. 94(4).

Refugee girls in Denmark have lower HPV vaccination rates, highlighting the need to address barriers and improve immunization programs

Girls from refugee families in Denmark were 40-56% less likely to receive HPV vaccine through 2 free-of-charge immunization programs than Danish-born girls, and the differences remained significant when income was taken into account. The odds of being vaccinated were lowest for refugees in the country ≤5 years and those from certain countries or regions, indicating the need to reduce cultural, social, and information barriers to immunization, as well as assess immunization programs across increasingly ethnically diverse societies.

Moller SP, Kristiansen M, Norredam M. 2018. Human papillomavirus immunization uptake among girls with a refugee background compared with Danish-born girls: A national register-based cohort study. European Journal of Cancer Prevention. 27(1).

The HPV vaccine can protect both young women and men from oropharyngeal cancers

HPV vaccine given to young women may also protect similarly-aged men against oropharyngeal cancers, which have been rising in incidence in the U.S. and Western Europe. In a small study in the UK, rates of oral HPV infections caused by HPV-16 were similar for males 12-24 years of age and vaccinated females (0% vs. 0.5%). This was considerably lower than the rates for unvaccinated females (5.6%) and men ≥25 years old (7.1%).

HPV-16 is the main HPV type linked to oropharyngeal cancers.

Mehanna H, Bryant TS, Babrah J et al.. 2018. Human papillomavirus (HPV) vaccine effectiveness and potential herd immunity for reducing oncogenic oropharyngeal HPV-16 prevalence in the United Kingdom: A cross-sectional study. Clinical Infectious Diseases. 69(8).

Introduction of vaccines provides opportunities for an expansion of health services

In Rwanda, HPV vaccine introduction through a new school-based delivery program provided the opportunity to offer additional health services to all school-children (girls and boys), including health promotion sessions, de-worming and opportunities for voluntary, free circumcision.

Torres-Rueda, S., Rulisa, S., Burchett, H.E., et al.. 2016. HPV vaccine introduction in Rwanda: Impacts on the broader health system. Sexual and Reproductive Healthcare. 7.

Long-term cancer survivors have an increased risk of later HPV infections

In a US-based study of more than 65,000 long-term survivors of pediatric and young adult cancers spanning nearly three decades, researchers found an increased risk of later HPV infections and malignancies among these survivors. Female survivors of childhood and young adult cancers were found to have a 40% greater chance of developing HPV-associated malignancies compared to cancer-naïve females. This risk was even greater in male cancer survivors who had a 150% relative excess of HPV malignancies compared to cancer-naive males.

Ojha, R.P., Tota, J.E., Offutt-Powell, T.N., et al.. 2013. Human papillomavirus-associated subsequent malignancies among long-term survivors of pediatric and young adult cancers. PLOS ONE. 8(8).

People who are HIV positive are at an increased risk of severe outcomes from human papillomavirus (HPV) infection

Human Papillomavirus (HPV) infections are more prevalent and persistent in HIV-infected individuals — HPV prevalence rates of 76% in HIV-infected women compared to the 46% prevalence rate in HIV-uninfected women. Cervical prevalence rates are also higher in HIV-infected women — between 48-73% in case compared to 28% in HIV-uninfected women. Additionally, HPV infections and HPV-associated diseases appear to exert a disproportionately higher burden of disease in HIV-infected women as opposed to HIV-uninfected women.

Kojic, E.M., Rana, A.I., and Cu-Uvin, A.. 2016. Human Papillomavirus vaccination in HIV-infected women: need for increased coverage. Expert Review of Vaccines. 15(1).