People who don't get the flu shot are being protected by those who do

Embargoed until: Publicly released: 2025-07-17 01:00

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Members of a community that take the seasonal influenza vaccine are likely lowering overall flu transmission and reducing the risk for those who haven't been vaccinated, according to an international modelling study. The team modelled various flu scenarios using population data from a US county and a flu vaccine with an effectiveness of 40%. Modelling various scenarios with flu seasons of different levels of transmission and different levels of flu vaccine uptake, the researchers say the burden of flu averted by vaccination ranged from 32.9% to 41.5%. While those who received a vaccine saw the best protection, the researchers say unvaccinated people had an indirect benefit if people around them were vaccinated, especially in low transmission scenarios.

Media release

From: JAMA

About The Study: In this analytical model study, influenza vaccination provided substantial benefit in reducing infections to both the vaccinated and unvaccinated portions of the population. Even when both vaccine effectiveness and vaccine uptake were low, vaccination showed marked reductions in disease burden for transmission levels characteristic of seasonal influenza. However, when the level of transmission was very high, even a highly effective vaccine did not protect unvaccinated individuals. These findings underscore the importance of vaccination in disease prevention and control and show that indirect benefits are limited in high transmission situations.

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Journal/
conference: JAMA Network Open

Research:Paper

Organisation/s: University of Pittsburgh, USA

Funder: This work was supported by grant U01-IP001141-01 from the Centers for Disease Control and Prevention.

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