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That's not necessarily always true. The halo effect varies depending on the transmissibility of the disease AND the number of people vaccinated. Even small nu
by kordless 13y ago
That's not necessarily always true. The halo effect varies depending on the transmissibility of the disease AND the number of people vaccinated. Even small numbers of vaccinations can decrease the spread of an infectious disease.
- bsder 13y ago> Even small numbers of vaccinations can decrease the spread of an infectious disease. Only of the vaccine is particularly effective in individuals (95%+). Pertussis seems to be a good counterexample. You really do need the herd immunity to keep it under control since individual immunity seems to be below 70% or so. In addition, non-vaccinated people tend to be clustered since anti-vaccination is a function of shared social situation (shared belief, religious affiliation, or low socioeconomic status). Consequently, you need MORE people vaccinated to control it, not fewer.
- Fomite 13y agoSpecifically, the critical % of people needed to be effectively vaccinated is 1 - (1/R0), where R0 is the "Basic Reproductive Number" of the disease. In English, how many people a single infective individual can be expected to infect in an entirely susceptible population.