NEW YORK – The mRNA coronavirus vaccines, i.e. those from Pfizer and Moderna, could offer longer-lasting protection than expected against Sars-CoV-2, thus reducing the need for periodic boosters.
The Associated Press reports, underlining how various clinical trials are underway and how experts have not yet come to establish what is the maximum coverage offered by these preparations. “I’d be surprised if we really needed an annual booster,” said Dr. Paul Offit, vaccine specialists at the Children’s Hospital of Philadelphia and advisor to the Food and Drug Administration (FDA), the US government agency that deals with the regulation of food and pharmaceutical products.
At least six to nine months – Once the original antibodies have vanished, the immune system can reactivate if a person is exposed to the coronavirus again. There is growing evidence that antibodies remain strong for at least six to nine months, if not longer, with Pfizer and Moderna vaccines. “I’m pretty optimistic. I would not rule out the need for a booster “or a third booster dose, aimed at understanding if repeated administrations are effective,” but the immune response so far seems really impressive, “explained University of Pennsylvania immunologist John Wherry.
The example of the other coronaviruses – A yardstick for comparison are other coronaviruses already known, namely those that cause the common cold. Wherry indicated that people tend to get reinfected every two to five years. Based on what is known about natural immunity to colds, “we expect our immunity to decrease. But we don’t know. For these mRNA vaccines, we could do better than nature, better than a natural infection, ”speculates the immunologist.
There is still a lot to discover – At the moment it is not known what is the threshold below which antibodies cannot reject the virus, without further help. That is a recall of the vaccine, which has been hypothesized by the manufacturing companies and also by various experts. Among them is Anthony Fauci: «What we are discovering right now is what the interval will be» between the administration of the first two doses and the booster.