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 Terms

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 against influenza and pneumococcus can reduce healthcare visits and antibiotic use, improving overall health

This systematic review suggests that vaccination against influenza and pneumococcus can reduce overall healthcare visits and antimicrobial consumption. Of the 26 studies included in the review, 23 found significant reductions in antimicrobial use in vaccinated individuals or groups. This evidence indicates that improved coverage with existing vaccines may significantly reduce antimicrobial demand.

Doherty TM, Hausdorff WP, Kristinsson KG. 2020. Effect of vaccination on the use of antimicrobial agents: a systematic literature review. Annals of Medicine. 52(6).

Increasing influenza vaccine uptake can help manage respiratory outbreaks and reduce strain on healthcare systems during COVID-19

The potential for a spike in COVID-19 concurrent with influenza season could threaten to overwhelm healthcare systems, particularly in resource-limited contexts. A double burden of influenza and COVID-19 cases could also increase risk of cross-infection and transmission in hospital settings. This mathematical modeling study found that increasing influenza vaccine uptake would help manage respiratory outbreaks coinciding with peak flu season and thus reduce the potential strain on healthcare systems responding to COVID-19.

Li Q, Tang B, Bragazzi NL et al.. 2020. Modeling the impact of mass influenza vaccination and public health interventions on COVID-19 epidemics with limited detection capability. Mathematical Biosciences. 325.

Immunization with pneumococcal and rotavirus vaccines can prevent millions of episodes of treatment with antibiotics

In this analysis of data from large-scale studies of households, two vaccines recently implemented in the WHO EPI, pneumococcal conjugate vaccines and live attenuated rotavirus vaccines, were estimated to confer 20% and 11% protection against antibiotic-treated episodes of acute respiratory infection and diarrhea, respectively, in the age groups with the greatest disease burden attributable to these pathogens. Under current coverage levels, pneumococcal and rotavirus vaccines are estimated to prevent 24 million and 14 million episodes, respectively, of antibiotic-treated illness each year among children in LMICs less than five years old. An additional 40 million episodes could be prevented through achievement of universal coverage targets.

Lewnard JA, Lo NC, Arinaminpathy N et al.. 2020. Childhood vaccines and antibiotic use in low- and middle-income countries. Nature. 581.

Seasonal flu programs help countries prepare for pandemics and reduce the burden of flu

Seasonal influenza programs can be cornerstones to pandemic preparedness and response. Using the 2009 WHO Vaccine Deployment Initiative as a case study, eligible countries with a seasonal influenza vaccine program were more ready to receive and use donated vaccines than those without a program. These findings suggest that robust seasonal influenza vaccine programs allow countries to test crucial regulatory and delivery systems that enhance pandemic preparedness while also reducing the substantial burden of seasonal influenza.

Porter RM, Goldin S, Lafond KE et al.. 2020. Does having a seasonal influenza program facilitate pandemic preparedness? An analysis of vaccine deployment during the 2009 pandemic. Vaccine. 38(5).

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).

Rotavirus vaccination saves money and prevents millions of cases, hospitalizations, and deaths

This study provided an updated model of the cost-effectiveness of rotavirus vaccination in children younger than 5 years across 73 countries previously or currently eligible for Gavi support. The researchers found evidence that rotavirus vaccination is still a cost-effective investment in Gavi countries, projected to save approximately $484 million (around $48 million per year) from the government perspective and $878 million (around $90 million per year) from the societal perspective between 2018 and 2027, by preventing 158.6 million cases of rotavirus gastroenteritis, 80.7 million outpatient visits, 7.9 million hospitalizations, 14.7 million Disability-Adjusted Life Years, and nearly 600,000 deaths.

Debellut F, Clark A, Pecenka C et al.. 2019. Re-evaluating the potential impact and cost-effectiveness of rotavirus vaccination in 73 Gavi countries: a modelling study. Lancet Global Health. 7(12).

Immunization campaigns against measles and rubella have improved routine immunization systems and disease prevention measures

A survey of 23 countries in all WHO regions found that activities to eliminate measles and rubella, including vaccination campaigns, have strengthened the countries’ overall routine immunization systems in a number of ways. These include microplanning that led to revised catchment populations and denominators for target-age children, expansion of cold chain systems that extended the reach of immunization, strengthening of surveillance and of outbreak preparedness and response for vaccine-preventable and other diseases.

Biellik RJ, Orenstein WA. 2018. Strengthening routine immunization through measles-rubella elimination. Vaccine. 36(37).

Immunizing infants with pneumococcal vaccines saves billions of dollars in treatment and societal costs worldwide

Vaccination of infants with pneumococcal conjugate vaccines in 180, from the health system perspective, would save an estimated $3.2 billion per year worldwide in treatment costs and an additional $2.6 billion in societal costs (from reduced missed work and out-of-pocket expenditures)- for a total of $5.8 billion. These savings would partially offset the estimated global cost of vaccination of $15.5 billion per year.

The cost estimates were calculated in international dollars.

Chen C, Liceras FC, Flasche S et al.. 2019. Effect and cost-effectiveness of pneumococcal conjugate vaccination: a global modelling analysis. Lancet Global Health. 7(1).