The independent evidence so far suggests that immunity will be measured in months.
https://www.israelnationalnews.com/News/News.aspx/299604
Corona Commissioner Prof. Nachman Ash was also asked to respond to reported evidence in recent weeks of a decline in the amount of antibodies observed among medical teams after receiving the second dose of the Covid-19 vaccine, and the question of whether this implied an expiration in the vaccine’s effectiveness.
Ash explained that an observed decrease in antibodies was to be “expected” and, in any event, the body has “other mechanisms of protection.”
“It is expected that there will be a decrease in the level of antibodies in the blood, and there are other mechanisms of protection, such that I don’t see a problem with it, and we will continue to monitor this detail as well as the [issue of] infections - which is even more important.”
Here is some data from one study:
“One dose helped protect against hospitalization, with effectiveness peaking about five weeks after immunization at 84% effective at preventing hospitalization.”
“But the follow-up data available beyond that time is where it gets concerning. Effectiveness peaked and then began to decline, going from 84% effective in the fifth week to 61% effective the following week and then 58% beyond then.”
“It’s unknown whether that trend would continue beyond that, as that’s all the data the researchers had available to crunch in the study. But the findings suggest that protection starts to wane from a single dose after five weeks or so.”
Here is a link to an Israeli chart which shows how quickly the decline in efficacy begins after the second shot.
https://twitter.com/dvir_a/status/1364240578922360833/photo/1
At a recent investor conference Pfizer said annual vaccination would be necessary and additional booster shots may be given.
Israel’s Prime Minister has said that Israel may need to vaccinate the public twice a year.
Sorry, here is the correct link to the Israeli chart
https://pbs.twimg.com/media/Eu7Au1OXMAUoEYN?format=png&name=small
They will also start vaccinating against influenza in both the early fall and a booster in late winter, to try to handle new strains that emerge. H1N1 likes to change.
Of course antibodies fall off. But the rest of the story is that it is driven into T memory cells which are not antibodies. This is where lasting immunity resides. And we know the vaccines produce robust T cell immunity.
People really don’t have a basic understanding of immunology but are happy to speak like experts in the field (not aimed at you just generally)