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What we know about COVID vaccine booster shots – and when we may need them



Now that nearly half of the U.S. population is fully vaccinated against COVID-1

9, many people are beginning to wonder how long the protection will last and whether they need a booster shot down the road.

Currently, there are more questions than answers about the possibility of needing an extra dose of COVID-19 vaccines to boost immunity over time. Dr. Betty Diamond, director of the Feinstein Institutes of Medical Research in Manhasset, NY, said more research is needed to determine if and when a booster will be needed.

“Vaccines are unstable or idiosyncratic,” she told Yahoo News. “So you can’t predict how long immunity will last when you develop a vaccine.”

Diamond explained that certain vaccinations, such as the polio vaccine, provide lifelong immunity to this disease, while others, such as tetanus or flu shots, generate defenses that may diminish over time. For example, to be fully protected against tetanus, the Centers for Disease Control and Prevention recommends getting a booster every 10 years; for influenza, it is advisable to receive a shot every year.

“We do not have the information we need about the SARS-CoV-2 vaccines,” she said.

However, some health authorities, including Dr. Anthony Fauci, the country’s leading infectious disease expert, said boosters will be needed. “I do not anticipate that the shelf life of vaccine protection will be infinite,” Fauci told a Senate subcommittee on May 26. “I can imagine that at some point we will need a booster,” he said, adding that he was “not quite sure when” it would be necessary.

In an Axios interview last month, Pfizer CEO Albert Bourla said the data he had seen so far supported “the notion that a booster is likely to be needed somewhere between eight and 12 months.” He added that for the first wave of Americans to be vaccinated, booster shots could be needed as soon as September or October.

Although experts are not entirely sure how long the COVID-19 vaccines offer protection, they believe it could last at least six months and probably a year. Some studies have analyzed blood samples from the first humans vaccinated in the trials to measure their levels of antibodies and immune cells fighting coronavirus. One such study, published by the New England Journal of Medicine this month, showed that antibodies elicited by the Moderna vaccine remained strong for at least six months.

It can be reassuring to know that researchers are working to determine if COVID-19 vaccine boosters are needed and that the government is preparing early for this option. The National Institutes of Health recently announced that they will conduct a new clinical trial in people who have been fully vaccinated with one of the approved vaccines to see if a booster of the Moderna shot will increase their antibodies and extend their protection. against the virus.

Vaccine manufacturers such as Moderna, Pfizer and Johnson & Johnson are also working on developing and testing booster shots in trials.

Yahoo News Medical Contributor Dr. Kavita Patel said early data suggest that some people, especially the elderly, immunocompromised and those who have had solid organ transplants, may need boosters “sooner rather than later.” This is because “they show lower levels of immunity, even with current vaccines. So there may have to be a priority for those populations with boosters, ”she said.

Another important question is whether people need booster shots tailored to specific variants. It is not yet clear, but some researchers suspect that the vaccines that elicited a high immune response to the original version of coronavirus will also continue to provide adequate protection against variants. Patel said the current vaccines so far protect against these new variants of concern worldwide, but “some to a lesser extent than the variants we had a year ago.”

In a study published last month, for example, researchers in Qatar examined the effectiveness of the Pfizer BioNTech vaccine – administered to more than 250,000 of the country’s residents between December and March – against variants B.1.1.7 and B. 1,351 th most common These, now designated as the alpha and beta of the World Health Organization’s new naming system for coronavirus variants, were dominant in the country at the time of the study. The study showed that although the vaccine was 100 percent effective in preventing serious disease, the efficacy against both variants was lower than that reported in the clinical trials.

In the Pfizer clinical trials, the vaccine showed an effect of 95 percent against the original version of coronavirus. But according to the study, the variant called alpha, first identified in the UK, lowered its efficiency to 89.5 percent. And the variant known as beta, which was first identified in South Africa, lowered the vaccine’s effectiveness to 75 percent.

Perhaps it would be more effective to have a booster designed to target a variant, but it is currently under investigation. Pfizer has begun testing both options – a booster targeted at the original form of the virus as well as one designed to protect against the beta variant.

Finally, some people wonder if it will be safe to change vaccine label if boosters are needed. Diamond said trials are underway to determine if this is possible.

“The actual antigen from SARS-CoV-2 is the same in all of these vaccines,” she said. “So the memory cells that you generated will be able to see it in the new vaccines or in the alternative vaccines. I think the expectation is that it will not be a problem to mix and match. ”

The bottom line, Diamond told Yahoo News, is that while there is much to learn about COVID-19 booster shots, current vaccines in the United States are “amazing,” and people should take advantage of the protection they offer.

“Vaccines are one of the jewels in the crown of medicine, and we must take advantage of them – just as we benefit from antibiotics when we need them,” she said.

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