The risk of breakthrough infections remains very rare, three studies have found

The Covid-19 vaccine continues to provide strong protection against serious illness and hospitalization, according to a study of more than one million people published Wednesday. Lancet infection..

Findings come as the United States prepares to get started Providing booster shots To all Americans later this month — a decision partially promoted by data federal authorities said it indicates that the ability of vaccines to control infection may be diminished.

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However, protection against the most serious forms of illness seems to be enduring.

New studies show that vaccines keep people away from hospitals and intensive care units and prevent death, said Dr. Paul Offit, director of the Vaccine Education Center at Philadelphia Children’s Hospital, who was not involved in the study. Said.

He said it was “the goal of these vaccines,” and the findings apply to “people of all ages and comorbidity.” Highly contagious delta variant..

In Lancet’s study, British researchers analyzed data from a project called ZOE Covid Study, Users report daily symptoms, vaccination status and other demographic information via the app.

Researchers examined data collected by more than one million people between December 2020 and July 2021. This period spanned both alpha and delta variant waves in the United Kingdom. Participants received either the Pfizer-BioNTech, Moderna, or AstraZeneca vaccine twice.

Overall, less than 0.2% of participants report breakthrough infections, and such cases are more likely to occur in people who are already considered vulnerable, such as the elderly and people with underlying illness. I have.

Most were mild when breakthrough infections occurred — only 6% of people with breakthrough infections reported symptoms. In addition, vaccination has been shown to reduce the risk of hospitalization by more than two-thirds.

Research also has the potential for development Long covid It was cut in half for fully vaccinated people. Long covid refers to people experiencing symptoms such as brain fog, malaise, and heartbeat for at least a month after infection, and in some cases much longer.

Two other studies published Wednesday also found that the incidence of breakthrough infections was very low.

First published in JAMA network openAnalyzed breakthrough infections among more than 5,300 vaccinated health care workers in Israel. Only 27 such infections have been found. No deaths were reported and only one patient required hospitalization. However, this study was completed before the Delta variant became the predominant strain in Israel.

The other is New England Journal of Medicine, Detected 94 symptomatic breakthrough infections in more than 16,000 healthcare professionals. The study, conducted until July, found that breakthroughs increased as delta variants prevailed.

Since the Covid-19 vaccine was launched in late 2020, researchers have closely tracked breakthrough infections.

Just because a breakthrough infection has occurred does not mean that the vaccine has stopped working. Rather, according to experts, breakthrough infections were always expected, as no vaccine is 100% effective.

“Vaccines are like guard dogs,” said Dr. Rachel Presti, an infectious disease specialist at Washington University in St. Louis. The guard dog will drive away most robbers, but thieves may be able to sneak up.

The results of the first phase 3 clinical trials of the first two vaccines approved in the United States set incredibly high standards. Pfizer-BioNTech reported 95% efficacy and Moderna reported 94% efficacy for symptomatic disorders.

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Dr. Avi Nashberg, an infectious disease specialist at Mayok Clinic in Rochester, Minnesota, said his great success could have inadvertently led to unrealistic expectations of the vaccine.

“I think the general public thought,’I’ve been vaccinated, so I should never get infected.'” I should be 100 percent protected, “Burke said.

The measles-mumps-rubella vaccine is considered to be the most effective vaccine in existence. Prevents 97% of measles cases..

However, part of the reason the vaccine works so well is that the measles virus is no longer widely distributed, so vaccinated individuals are much less exposed and have the potential for breakthrough infections. It’s even lower.

“The fewer viruses that circulate, the more effective the vaccine works,” Presti said.

according to Centers for Disease Control and Prevention data, Community infections are currently thought to be high in 94% of US counties.

In both the JAMA Network Open and New England Journal of Medicine studies, breakthrough infections are more common at home, even though healthcare professionals spend their days around Covid’s cases in hospitals. understood.

“When we work in the hospital, we are very conscious of exposure,” Burke said. “I’m less alert when I’m at home.”

It’s not surprising or discouraging that people become more sensitive when they’re not wearing masks or when they’re physically separated, Burke said. Rather, it shows that adding a protective layer can increase the efficacy of the vaccine.

“What we are hearing more and more is [vaccinated health care workers] Dr. Francesca Triani, an infectious disease specialist at the University of California, San Diego and lead author of the New England Journal of Medicine research, said:

“The good news is that these infections are still very mild,” she said.

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