My understanding is that circulating COVID-19 antibodies drop sharply a month or two after infection or vaccination, but disease resistance through T cell memory can persist a long time for some diseases (TBD for COVID).
I had heard that very few people have been re-infected by COVID-19, and virtually none died from it.
What is the thinking, on how long the immunity from COVID vaccines or infection will last?
Vaccines should drive Tcell immunity. Literature demonstrates that the second shot with Pfizer and Moderna do just that. If there were reinfection, we would see the pandemic raging in perpetuity,
I think that Tcell immunity likely does exist with those who were naturally infected and it is the reason that we are seeing the emergence of herd immunity in multiple areas of the country.
I still stand by that by July between vaccination which accelerates herd immunity and natural disease, this will be done.
Don’t know for sure yet but it would be unusual for immunity not to last months to years.
https://www.advisory.com/en/daily-briefing/2021/03/02/reinfection
CDC study suggests some patients could face more severe Covid-19 with reinfection
For the report, researchers looked at two separate outbreaks that occurred three months apart at a skilled nursing facility in Kentucky. The first outbreak at the facility occurred in July 2020.
According to the researchers, among 12 of the residents who tested positive during the first outbreak and were still living at the facility in October, five—ranging in age from 67 to 99—tested positive again during the second outbreak.
Three of the five residents had asymptomatic infections during the first outbreak, but all residents experienced symptoms of Covid-19 during the second infection. One required hospitalization and later died, the researchers noted.
Further, according to the researchers, the two residents who had symptomatic cases of Covid-19 during the first outbreak experienced more severe symptoms during their second infection.