We have to think of immunity as non-binary. Everyone has some degree of immunity to everything, to the extent that immunity means not being killed by it within a couple of days of exposure. Natural immunity to SARS-CoV-2 in late 2019 varied from 0.1% to close to 100% (there were asymptotic cases even then), with older people more at risk of being at the 0.1% end and not all that many at the 100% end. Vaccines and recovery move us all up the scale, time moves us back down. Right now a great many positive LFTs are completely asymptomatic (people are only taking them because they have to for work, or because a family member has tested positive), suggesting that a lot of people are close to the 100% end.Herainestold wrote: ↑Sun Jan 30, 2022 11:16 pmI think that's been debunked. Even Covid doesn't give immunity against Covid. (Lots of Delta sufferers are getting Omicron).
Could still be immune though.Some people just are.
My understanding is that the 1918 flu pandemic was also caused by a novel virus, and since then we have built up a degree of collective immunity to its descendants by a combination of getting flu, annual jabs, and mutations that on average make it less nasty (but sometimes not).
It would be interesting (but unethical and impossible) to see what happened if you kept someone away from the common cold for the first 70 years of their life and then infected them. It might be quite bad.
Both first-generation lockdown skeptics and over-enthusiastic vaccine advocates (who imagined that vaccines would stop transmission and for a long period) are made to look silly by these examples. Nobody thinks they will be immune (in the binary sense) from the flu for more than a season after catching it, or a cold for more than a month.