Herd immunity is the indirect protection from an infectious disease that occurs when a sufficiently large proportion of a population is immune, through vaccination or prior infection, so that sustained chains of transmission cannot be maintained and even non-immune individuals are protected. The threshold fraction r…
Herd immunity is the indirect protection from an infectious disease that occurs when a sufficiently large proportion of a population is immune, through vaccination or prior infection, so that sustained chains of transmission cannot be maintained and even non-immune individuals are protected. The threshold fraction required depends on the pathogen's basic reproduction number: more transmissible agents demand higher immune coverage to interrupt spread. For respiratory viruses such as SARS-CoV-2, attaining and sustaining herd immunity is complicated by waning immunity, the emergence of antigenically distinct variants, heterogeneous mixing, and vaccine hesitancy, all of which can shift the effective threshold and erode population-level protection over time. Research in this area examines vaccine development and uptake, determinants of willingness to vaccinate across different populations and risk groups, and the predictors of hesitancy that limit coverage. It also considers how non-pharmaceutical measures, such as masking and social distancing, complement immunity to reduce transmission during periods when coverage is incomplete. Modeling approaches quantify the coverage needed under different assumptions about contact patterns and immune duration. As a concept, herd immunity links immunology, epidemiology, and public-health policy, framing vaccination not only as individual protection but as a collective good that shields the vulnerable who cannot themselves mount adequate immunity.
6 peer-reviewed articles, ranked by relevance. Each links to its DOI.
The 6 articles above have been cited 9 times in the scholarly literature. Citation data via OpenAlex and Crossref, updated Jun 2026.
A sample of recent works citing this journal's research on Herd Immunity, linking to each citing work.