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

Immunization with PCV reduces pneumonia cases and saves lives, easing economic burden on families and health systems

A surveillance study over a 10-year period in the Gambia found that routine introduction of PCV led to a 33% reduction in the incidence of radiological pneumonia and a 27% decline in pneumonia hospitalizations in children. Reducing the rate of pneumococcal disease will not only save lives but will also reduce the substantial economic burden placed on families and health systems.

Mackenzie GA, Hill PC, Jeffries DJ et al.. 2021. Impact of the introduction of pneumococcal conjugate vaccination on invasive pneumococcal disease and pneumonia in The Gambia: 10 years of population-based surveillance. The Lancet Infectious Diseases. 21(9).

Immunization can prevent severe respiratory infections in children, reducing hospital admissions and deaths worldwide

A systematic review of the global burden of acute lower respiratory infections associated with seasonal influenza in children under 5 years found that just in 2018 these infections led to an estimated 870,000 hospital admissions and 15,300 in-hospital deaths. About 23% of these hospital admissions and 36% of the in-hospital deaths were in infants under 6 months and about 82% of the in-hospital deaths occurred in low-income and lower-middle-income countries.

Wang X, Li Y, O'Brien KL et al.. 2020. Global burden of respiratory infections associated with seasonal influenza in children under 5 years in 2018: a systematic review and modelling study. Lancet Global Health. 8(4).

Immunization against rotavirus significantly reduced hospitalizations and emergency visits in children

Prior to the introduction of rotavirus vaccines in the U.S., there were an estimated 205,000 – 272,000 emergency department visits and 55,000 – 70,000 hospitalizations due to rotavirus in children each year. A series of studies found that hospitalizations in children under five due to rotavirus declined, on average by 80% from the pre-vaccine to the post-vaccine era, while both outpatient visits and emergency department visits due to rotavirus declined 57%.

Pindyck T, Tate JE, Parashar UD. 2018. A decade of experience with rotavirus vaccination in the United States – vaccine uptake, effectiveness, and impact. Expert Review of Vaccines. 17(7).

Immunization against rotavirus reduced hospitalizations in both children and adults via herd protection

Several studies in the U.S. have shown that hospitalizations due to rotavirus fell sharply in children too old to be vaccinated as well as in adults after rotavirus vaccines were introduced, indicating herd protection. In one large study, rotavirus hospitalizations in 2008 — two years after the first vaccine was introduced — declined by 71% in 5-14 year old children and by 65% in 15-24 year olds compared to the pre-vaccine period.

Pindyck T, Tate JE, Parashar UD. 2018. A decade of experience with rotavirus vaccination in the United States – vaccine uptake, effectiveness, and impact. Expert Review of Vaccines. 17(7).

Immunization reduced hospitalization disparities for children from ethnic minorities

In New Zealand, Maori and Pacific children have historically suffered high hospitalization rates for invasive pneumococcal disease (IPD), all cause pneumonia (ACP), and otitis media. Following the introduction of conjugate vaccines in the country, Maori and Pacific children’s rates of admission for IPD dropped by 79% and 67%, respectively, while significant reductions in ACP and otitis media admissions were also noted, resulting in reductions in disparities for these populations.

Petousis-Harris, H., Howe, A.S., Paynter, J., et al.. 2018. Pneumococcal Conjugate Vaccines Turning the Tide on Inequity: A Retrospective Cohort Study of New Zealand Children Born 2006-2015. Clinical Infectious Diseases. 68(5).

Immunization can prevent common illnesses that strain hospital resources

In a Bangladeshi study, pneumonia and acute diarrhea were the first and third most common reasons for childhood hospital admission with over half (54%) of the acute diarrhea admissions caused by rotavirus. One in four children taken to this large pediatric hospital were refused admission because all beds were occupied. Vaccination could have prevented children with rotavirus from requiring essential hospital resources when one in four children refused admission had symptoms of pneumonia.

Saha, S., Santosham, M., Hussain, M. et al.. 2018. Rotavirus Vaccine will Improve Child Survival by More than Just Preventing Diarrhea: Evidence from Bangladesh. American Journal of Tropical Medicine and Hygiene. 98(2).

Immunization against rotavirus has led to significant decreases in hospital admissions and gastroenteritis cases

Several countries have seen a significant decrease in the number of rotavirus-related hospital admissions in rotavirus unvaccinated children ages 2-5 years who were not age eligible to receive the vaccine post introduction. The US had a 41-92% decrease, Australia had a 30-70% decrease, Belgium had a 20-64% decrease, Austria had a 35% reduction and El Salvador had a 41-81% decrease. In addition, there was a reduction in hospitalizations due to gastroenteritis of any cause by 17-51% in the US and 40% in Australia.

Patel, M.M., Glass, R., Desai, R., et al.. 2012. Fulfilling the promise of rotavirus vaccines: how far have we come since licensure?. Lancet Infectious Diseases. 12(7).