Thread: Anti Vaxxers
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Old 23rd Feb 2019, 01:17
  #33 (permalink)  
nonsense
 
Join Date: Apr 2008
Location: on the ground
Posts: 222
The vaccination rate required to achieve herd immunity obviously varies widely with factors such as how effective the vaccine is in preventing the vaccinated individual from being infected, how easily the target disease infects unvaccinated individuals, and even how quickly the surrounding society detects and isolates infected individuals.

The goal of vaccination is not just to protect the individual (eg: travel vaccinations), but the protect the society by reducing the number of new infections per infected person below one. This is herd immunity - the disease fizzles out rather than exploding into an epidemic.

If a vaccine is only say 80% effective, then more of the population needs to be vaccinated to ensure that each infected person infects on average less than one more person.
If a disease is readily detected and quarantined before infecting more people, then doing so obviously reduces transmission and reduces the rate of vaccination required to achieve herd immunity.

For measles, it is generally reckoned that ~90 to 95% vaccination is required..
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