A lot of data indicate that immunity wanes.
"That’s too long to wait, Topol said. Based on the research, Topol said immunity may begin to go down at around the five- or six-month mark, leaving vaccinated people more vulnerable to infection."
COVID vaccine efficacy wanes amid delta variant surge, CDC study shows (usatoday.com)
Here is the article I was speaking of. It is a pretty long article, but quite interesting, I think. I've snipped a few things and put them here .....
A series of new studies, including two led by Ellebedy, suggests that mRNA vaccines like those from Pfizer-BioNTech and Moderna trigger the immune system to establish long-term protection against severe COVID-19 — protection that likely will last several years or even longer, Ellebedy says.
To understand what he's talking about, let's say you received the second Moderna or Pfizer vaccine six months ago. Right away, your immune system got to work and began making antibodies.
"In every single immune response, there is a sharp rise in antibodies, a period of sharp decline, and then it starts to settle into a more stable nadir."
The media has largely focused on this decline of antibodies as the cause of "waning immunity." And it's true, Bhattacharya says, that this decline in antibodies, combined with the high potency of the delta variant, which began dominating many countries this year, is likely increasing the rate of infection in fully vaccinated people.
"If you get a big dose of delta, as the variant often gives, the virus can slip past the initial wall of antibodies," he says. "So I think we may be seeing some signs of that. But the [level of breakthrough infections] is probably not as dramatic as I think it's being made out to be."
Why? Because the media has largely overlooked several key facts about the antibodies present eight months after the vaccine. For starters, they're more powerful than the original ones triggered by the vaccine, Bhattacharya says.
"The quality of the antibody improves over time. It takes far fewer of those new antibodies to protect you," Bhattacharya says. "So I think that worrying about antibody decline is not something that's productive," he adds.
At the same time, the cells that make these souped-up antibodies become souped up themselves, he adds.
"They're estimated to spit out something like 10,000 antibody molecules per second." So you don't need many of these cells to protect you against a future infection.
On top of that, these cells learn something remarkable in the training center: how to persist.
Immunity To COVID-19 Could Last Longer Than You'd Think
