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Do you need to get a 4th Covid shot?

As the number of cases of coronavirus continues to plummet across the United States, people’s immunity may also be weakened. Several studies have shown that mRNA booster shots have been successful in preventing hospitalization and death, but their effectiveness against infection has diminished.

So it’s no wonder that at the end of Thursday, Moderna asked the Food and Drug Administration for an emergency use of a second booster shot for every adult. The company’s request was made a few days after Pfizer and BioNTech applied for a second booster emergency use authorization. Coronavirus vaccine for people over 65 years old.

Modana said its much broader demands give disease control and prevention centers and healthcare providers more flexibility in deciding who will benefit most and when by taking additional booster shots. ..

“Scientists and doctors are very different about this,” said Dr. Yvonne Maldonado, a pediatric infectious disease doctor at Stanford University. “I don’t think everyone should have another booster right now.” I am. You should not start reviewing the available data. “

Currently, the fourth dose is only allowed for people with weakened immunity. This includes teens and adults who have had an organ or stem cell transplant, are receiving chemotherapy for cancer, have advanced or untreated HIV, or are immunosuppressed. Drug.

It is difficult to predict when the FDA will approve a second booster (or fourth dose) for all adults. The FDA will convene an advisory board next month to discuss this issue. The Commission may move swiftly on Pfizer’s application for seniors, but it’s unclear if Modana’s broader demands will get a green light.

“We know that people over the age of 65 are at greater risk of dying than people under the age of 65, even if they are vaccinated,” said Dr. Carlos del Rio, an infectious disease specialist at Emory University. I am saying. If people are boosted. “

One of the reasons older people benefit from additional booster shots is that as the immune system ages, it tends to weaken and does not produce the same amount or quality of antibodies as it did when young. In addition, older people are often at increased risk of serious illness, with other medical conditions that draw attention to the body, Dr. Christian Gabler, an immunology researcher at Rockefeller University in New York City. A factor of severe Covid, “he said.

Pfizer and BioNTech rely heavily on evidence from two studies conducted in Israel to justify seeking a second booster for people over the age of 65 and received a fourth injection. It suggests that people are less likely to get the virus than those who receive it. Administered 3 times.

In a study published on a preprint server in February, scientists reviewed the health records of about 1.1 million people over the age of 60 who received a fourth dose and compared it to those who received three doses. did. , As with those of severe illness, were lower in those who took the fourth shot.

A second study, published Wednesday in the New England Journal of Medicine, examined Israeli healthcare workers of all ages, and both Pfizer and Moderna’s fourth shot increased antibody levels, but prevented infection. I wasn’t very good at it.

However, experts warned that the data available are still preliminary and have not yet shown how long the benefits of the fourth dose will last.

Experts tracking Covid-19 are careful not to give specific advice on when to receive a fourth dose if safety and efficacy data are still limited. ..

For example, if another surge is imminent, older people may benefit from taking additional shots as soon as they are approved, but if the next wave does not occur until summer or autumn. , Getting a booster can be counterproductive. Because current vaccines are based on the original strain of coronavirus, obtaining a booster may have little effect on protection from future variants.

Dr. Amy Sherman, an infectious disease specialist at Brigham and Women’s Hospital in Boston, said: Not perfect at the time of knowing the clear seasonality, but knowing the exact tempo and dynamics of Covid and the new variants. “

That said, if an adult over the age of 65 is allowed a fourth shot and months have already passed since he got his first booster, he said, “Start thinking about whether you need a booster now. “I will,” said Dr. Del Rio.

For healthy people under the age of 65, most experts agree that three doses are currently sufficient. For example, people in their 20s and 30s who have already been vaccinated three times have little protection. From the additional shot, Dr. Gabler said.

“It may turn out that the fourth dose is wise, but at this point I think we should focus on the third dose,” he said.

Dr. Del Rio agreed, “I’m more worried about the millions of Americans who are unvaccinated or only partially vaccinated.” Vaccinated people nationally and globally can have a significant impact on reducing viral infections and reducing new variants, and anyone can return to normal life, Dr. Del Rio said. rice field.

Pfizer and Modena are testing a new Omicron-specific version of the Covid Booster. Other researchers are investigating vaccines that boost nasal mucosal immunity and protein-based shots. In the future, it may be better protected from coronavirus.

“We really need to think carefully about our vaccine strategy. Existing vaccines cannot completely prevent infections or prevent all illnesses, so our goal is to repeat boosters and vaccines. We need to think of what it is as a society, so at what point are we satisfied with the asymptomatic or mild infection of the population while being able to protect vulnerable people? “

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