The number needed to vaccinate to achieve herd immunity depends on if prior exposure to other coronaviruses confers some partial degree of immunity and also how many people have had COVID19 already in a population (presuming immunity after infection, but a necessary assumption if we are to get a working vaccine), as well as what the transmissibility of the virus is, which we only have estimates for right now.
I think if we can vaccinate 50% of the population, we'd be in pretty good shape. It's more people than get the annual flu shot.
Even after herd immunity, non immune individuals would still be at risk, and you could get significant outbreaks if you have a big cluster of people who are nonimmune, say a school or church of non-vaxxers.
I think if we can vaccinate 50% of the population, we'd be in pretty good shape. It's more people than get the annual flu shot.
Even after herd immunity, non immune individuals would still be at risk, and you could get significant outbreaks if you have a big cluster of people who are nonimmune, say a school or church of non-vaxxers.