- Jan 15, 2013
- In Orbit
That would depend on that perennially-missing "denominator" in the calculations (i.e. the true "how many of us actually had it" even if we didn't know it - again, customer's son is FDNY and he, and the better part of his company, tested positive back in the spring, and the most he can remember having had is a slight headache). And this is a coronavirus and antibodies (as opposed to T-cells) are not likely to play a big role in immunity.The definition of herd immunity has not changed. One bit of information your quotes miss is that the percentage of the population requiring immunity or antibodies has always varied depending on the disease, based on how infectious it is. For some diseases, natural herd immunity from exposure is fine, since it isn't very infectious and not many people will be required to have it. For Covid-19, it is believed that 60% or more of the population will require immunity. The consequences of having 200 million people naturally infected with Covid-19 were deemed severe enough that most people don't _want_ to see herd immunity achieved through natural infection, only through vaccination. You could still get there naturally, it just wouldn't be good.