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).

The introduction of PCV13 vaccine in Tennessee reduced racial disparities in pneumococcal disease

Population-based surveillance data collected in the state of Tennessee from 1998 – 2016 found that the introduction of PCV13 was associated with reductions in socioeconomic and racial disparities in PCV13-serotype invasive pneumococcal disease (IPD). PCV13 introduction was associated with the prevention of IPD in the overall population as well as substantial decreases in racial disparities in IPD over time between Black and White populations. Before PCV13 was introduced, Black people in the study had an IPD incidence 1.5 times higher than White people – 24.7 and 16.4, respectively. After PCV13 introduction, Black people had an IPD incidence 1.15 times the incidence among Whites: 15 and 13.1, respectively.

Raman R, Brennan J, Ndi D et al.. 2021. Marked Reduction of Socioeconomic and Racial Disparities in Invasive Pneumococcal Disease Associated With Conjugate Pneumococcal Vaccines. The Journal of Infectious Diseases. 223(7).

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).

A school-based flu vaccination program in California led to higher vaccination rates, fewer absences, and less flu transmission

A school-located influenza vaccination program implemented in 95 preschools and elementary schools in California was associated with increased influenza vaccination coverage, decreased school absences due to illness, and lower influenza transmission across the community. The 11% increase in flu vaccination in children enrolled in target schools was associated with fewer flu hospitalizations in the community, including 160 fewer influenza hospitalizations per 100,000 among people aged 65 and older.

Benjamin-Chung J, Arnold BF, Kennedy CJ et al.. 2020. Evaluation of a city-wide school-located influenza vaccination program in Oakland, California, with respect to vaccination coverage, school absences, and laboratory-confirmed influenza: A matched cohort study. PLoS Medicine. 17(8).

Immunizing pregnant women protects infants from influenza, with 56% efficacy in the first 2 months of life

A pooled analysis of three randomized controlled trials conducted in Nepal, Mali, and South Africa between 2011 and 2014 found that immunization during pregnancy provided protection against influenza to young infants from birth through 4 months of age. Protection against infant influenza was greatest in the first 2 months of life, with 56% efficacy, and the pooled efficacy of maternal vaccination to prevent infant laboratory-confirmed influenza up to 6 months of age was 35%.

Omer SB, Clark DR, Madhi SA et al.. 2020. Efficacy, duration of protection, birth outcomes, and infant growth associated with influenza vaccination in pregnancy: a pooled analysis of three randomised controlled trials. The Lancet Respiratory Medicine. 8(6).

Influenza vaccination for healthcare workers reduced sick days during flu seasons

Healthcare workers who received an influenza vaccine missed fewer days of work compared to non-vaccinated peers (1.74 vs 2.71 days/person). The study took place at a large Italian hospital that employed approximately 5,300 healthcare workers. The researchers examined a severe influenza season (2017/2018) as well as three moderate flu seasons (2010-2013).

Gianino MM, Kakaa O, Politano G et al.. 2021. Severe and moderate seasonal influenza epidemics among Italian healthcare workers: A comparison of the excess of absenteeism. Influenza and Other Respiratory Viruses. 15(1).

Increasing influenza vaccination coverage by 10% leads to a 65% decrease in antibiotic use

A retrospective analysis of influenza vaccination coverage and antibiotic prescribing rates from 2010 to 2017 across states in the United States, controlling for differences in health infrastructure and yearly vaccine effectiveness, found that a 10-percentage point increase in influenza vaccination coverage was associated with a 6.5% decrease in antibiotic use across all age groups, equivalent to 14.2 fewer antibiotic prescriptions per 1000 individuals.

Klein EY, Schueller E, Tseng KK et al.. 2020. The Impact of Influenza Vaccination on Antibiotic Use in the United States, 2010–2017. Open Forum Infectious Diseases. 7(7).

Influenza vaccination in patients with diabetes reduces the risk of death and complications

In patients with diabetes, influenza vaccination was associated with a reduced risk of all-cause death, cardiovascular death, and death from acute myocardial infarction (heart attacks) or stroke. The analysis included medical records from 241,551 adult patients in Denmark across nine consecutive influenza seasons (2007 to 2016). Influenza vaccination was associated with a reduced risk for being admitted to the hospital with diabetes-related complications, like diabetic ketoacidosis, hypoglycemia, or coma.

Modin D, Claggett B, Køber L et al.. 2020. Influenza Vaccination Is Associated With Reduced Cardiovascular Mortality in Adults With Diabetes: A Nationwide Cohort Study. Diabetes Care. 43(9).

Introduction of PCV10 reduced antimicrobial use for acute otitis media, saving healthcare costs and combating antimicrobial resistance

The 2010 introduction of PCV10 for infants in Finland led to an estimated 15% reduction among unvaccinated children in purchases of antimicrobials recommended for acute otitis media (AOM), the most common reason for antimicrobial use in many countries. The indirect effects of PCV10 introduction contribute to health care savings and may also help to combat antimicrobial resistance.

Palmu AA, Rinta-Kokko H, Nohynek H et al.. 2020. Indirect Impact of Ten-valent Pneumococcal Conjugate Vaccine Program on Reducing Antimicrobial Use and Tympanostomy Tube Placements in Finland. The Pediatric Infectious Disease Journal. 39(9).