• Seriously? So even if you get vaccinated, you only have roughly a 50% less chance of getting the flu?

    But that becomes material if it means everyone infects half the number of people.

    If R is 1.5 for example, and you start with 100 people with the virus, after 5 rounds you'd have 10*(1.5^5) = 75.9 infections.

    With a 50% effective vaccine then that 1.5 I'd have thought becomes 0.75, so after 5 rounds the 10 people with the virus is 2

    (I'm sure I've vastly simplified things, but a number that doesn't look too spectacular from the point of view of one person can actually be significant when applied to an exponential spread across a population)

    Edit: the above assumes the entire population have received the vaccine, which is unrealistic. But principle is still there

  • Indeed. Even a partially effective vaccine has a massive effect on transmission rates. The maths is really quite simple. The smallpox vaccine wasn't 100% effective. Still didn't stop it being used to wholly eradicate smallpox.

  • Ah, yes. That makes a lot of sense now. Cheers

  • If R is 1.5 for example, and you start with 100 people with the virus, after 5 rounds you'd have 10*(1.5^5) = 75.9 infections.

    100*(1.5^5) = 759 active infections

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