All the studies I have seen so far show declining duration. And none of the scientists I have read expect immunity to last between 1 and 3 years. Most have suggested months.
Pfizer during an investors conference call last week indicated that they expect annual revax and potentially a 3rd booster shot. Of course that info was provided in the context of earnings expections...:-)
I have seen only one data point on duration out of Israel (about a month old.) I can’t link it because it was a screen shot of a graph. But, it showed high (over 95%) peak efficacy ten days after the second dose, slipping slightly over the next 10 days, but still over 90% and then further slippage to 87% during the final 10 days. They have offered no further info past the 35 days post vax.
I found the more concerning info in the second link to the German study I posted. 31.3% of elderly showed no detectable neutralizing antibodies compared to 2.2% in younger group.
They have told us all along that the elderly have less adverse effects from the vax. The data so far in several studies indicating that they get less efficacy may explain the less adverse effects.
My friend got a second Moderna shot at the VA a couple of weeks ago, and they discussed something about a third shot in the Fall. He was not clear on it.
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?
RC_one: What is your view, on how long immunity is likely to last, from COVID vaccines, or infections?