Data reveals how long the third hit is stored

Increase lifespan: data reveals how long the third hit is retained

Issue: Michaeleen Doucleff | NPR

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Thursday, January 20, 2022

Washington, D.C. (NPR) – We’ve known for a month that the third injection of the vaccine is essential to protect against infection with the Omigrant variant – and to get people out of the hospital.

Now researchers in the UK have their first estimate of how long Pfizer’s third vaccine will last. And the conclusions are mixed.

Vaccine protection may be short-lived, less than six months, but protection against severe disease appears to be much stronger, according to researchers from the UK Health Care Agency. Reported Friday.

In particular, after the third injection of Pfizer’s vaccine, the researchers found that protection against symptomatic infection was much better. Two weeks after the shooting, the booster reduced the risk by about 70%.

But that security quickly waned. Within three months, a reminder of symptoms reduces the risk of infection by only about 50%.

In a moment To analyse, British researchers predict that safety will drop even further, to around 40% four months after the third shot is taken.

“Vaccine effectiveness against infection depends on our antibody levels because in fact they are our first line against SARS-CoV-2,” the immunologist said. Jennifer Comerman at the University of Toronto.

With any vaccine, antibody levels increase rapidly immediately after vaccination and then decrease again over time. “It’s completely natural and expected,” he said, “so in terms of protection against infection, we would see some protection with boosters, but that protection would diminish.”

“Also keep in mind that Omigron is very different from the original SARS-CoV-2, which is why we were immunized,” Komerman added. “So our defense was a bit of a success in terms of the ability of these antibodies to identify Omigrants.”

On the other hand, he says, protection against acute disease is less dependent on antibodies. Vaccines stimulate other parts of the immune system to help control infection.

“So the drop in antibody levels can make you more susceptible to infection, but you don’t have to be infected – it’s a different type of fish.”

In fact, a British study found that boosters offer better protection against serious illnesses than against infections. Specifically, the researchers found that after the third injection of Pfizer, protection against hospitalization was 95% (two weeks after injection) and up to 80% four months later.

In comparison, with just two injections of the vaccine, protection against acute disease fell to 40% after six months.

The researchers only had short-term data for modern vaccines, but their findings echo Pfizer’s numbers based on how similar these mRNA vaccines are and how they behave comparable to the delta variant.

Study results raise questions about vaccine’s future, immunologists say Deeptha Bhattacharya at the University of Arizona.

“I don’t think it’s a coherent strategy to have people get a booster shot for the same shot every two or three months. People won’t do that. I felt sad after taking the second shot .”

Perhaps, instead, the goal will need to be changed to ensure that everyone is protected from serious illness in the long term of stopping infection.

“Can we get to the point where public health officials recommend an injection once a year,” Bhattacharya said. “I think it’s very possible. Now every year the question is different whether everyone needs this vaccine to prevent serious disease, and we have to wait for more data.

He thinks that with the onset of flu season, the occasional COVID outbreak might be a bit more predictable so people can get a boost before the expected outbreak, which provides short-term protection. against infection when it is most needed.