VoICE Immunization Evidence: Herd effects

Topics

A woman carrying vaccines

Search for immunization evidence

The VoICE tool allows you to search for research studies and published evidence based on a topic, location, and disease or vaccine.

Search VoICE

Pneumonia vaccines and poverty

Childhood pneumonia takes the lives of nearly 100 children each hour, and disproportionately affects children in the poorest households. Read on to find out how vaccines protecting against pneumonia can be our secret weapons in the war on poverty.

Learn More

Herd Effects

Herd effect (or ‘herd immunity’) occurs when a large enough percentage of a population has been immunized against an infectious agent to dramatically decrease circulation and transmission of the infection to the point where unimmunized individuals are indirectly protected. For some vaccine-preventable diseases, such as pneumococcal disease, the herd benefit to unvaccinated individuals is quite significant and carries demonstrable positive Economic benefits above and beyond the direct benefits to those who are immunized.
2 Key Ideas, 4 Sources
Key Idea

In a study in Rwanda, the number of admissions to hospital for diarrhea and rotavirus fell substantially after rotavirus vaccine implementation, including among older children age-ineligible for vaccination, suggesting indirect protection through reduced transmission of rotavirus. Two years after rotavirus vaccine introduction, the country saw nearly 400 fewer hospital admissions for diarrhea among young children at 24 district hospitals.

View Source >

Children with cancer often rely on herd immunity as protection from vaccine-preventable diseases, so vaccinating family members and health workers is critical. Herd effects may be the only source of protection against diseases in which the vaccines are not recommended for immunosuppressed children, such as the measles vaccine.

View Source >

Key Idea

This study based on active surveillance in the US before and after introduction of PCV estimated 38,000 cases of invasive pneumococcal disease were averted in the first 5 years of vaccine use and an additional 71,000 cases of disease were prevented through herd effects.

View Source >

Assuming 90% coverage, a program in The Gambia using a 9-valent PCV (PCV9) would prevent approximately 630 hospitalizations, 40 deaths, and 1000 DALYs, over the first 5 years of life of a birth cohort. The estimated cost would be $670 per DALY averted in The Gambia.

View Source >

A woman carrying vaccines

Search for immunization evidence

The VoICE tool allows you to search for research studies and published evidence based on a topic, location, and disease or vaccine.

Search VoICE

Pneumonia vaccines and poverty

Childhood pneumonia takes the lives of nearly 100 children each hour, and disproportionately affects children in the poorest households. Read on to find out how vaccines protecting against pneumonia can be our secret weapons in the war on poverty.

Learn More