Live Covid-19 updates: China, Omicron and vaccine news

Credit…Mike Kai Chen for The New York Times

A booster shot of the coronavirus vaccine made by Pfizer-BioNTech raised the level of neutralizing antibodies against the original version of the virus and the Omicron variant in a small trial in children aged 5 to 11, the authorities announced on Thursday. companies.

If the companies’ claims of a strong immune response are accepted by federal regulators, the government could expand eligibility for booster doses to include an additional 28 million children.

The Pfizer and BioNTech study, which the companies described in a brief press releaseincluded 140 children who received a booster six months after their second injection.

The children showed a six-fold increase in antibody levels against the original version of the virus one month after receiving the booster, compared to one month after receiving a second dose. Lab tests on blood samples from a subgroup of 30 children also showed 36 times the level of neutralizing antibodies against the Omicron variant compared to levels after just two doses, according to the press release and a gatekeeper. -word of Pfizer.

The study did not show the lifespan of the antibodies, nor test the effectiveness against Covid disease. The data has not been published or peer reviewed.

Antibodies are the immune system’s first line of defense against infections. They are expected to increase after an additional dose; how quickly that protection wanes is an ongoing concern for experts, regulators and vaccine makers.

The companies said they will seek emergency approval from the Food and Drug Administration for a booster for children ages 5 to 11 “in the coming days.” The agency generally acted within a month of receiving these requests.

Currently, Americans 12 and older are eligible for at least one booster, and about 30 million people age 50 or older are eligible for a second. Studies suggest that children ages 5 to 11 may especially need a booster.

New York State researchers recently found that while two Pfizer injections protected children in this age group against serious illnesses, they provided virtually no protection against symptomatic infections, even just one month later. full vaccination.

“I think ultimately, to protect yourself from Omicron, we know from studies and from adults and teenagers that you need three doses,” said health expert Dr. Kathryn M. Edwards. pediatric vaccines at Vanderbilt University School of Medicine. . “So I think the FDA will probably approve the third dose for kids ages 5-11.”

The companies’ announcement comes as new virus cases in the United States are rising slightly again after two months of sustained declines. The upturn was particularly noticeable in the Northeast, where the Omicron subvariant known as BA.2, now the dominant version of the virus in the United States, first took hold.

Dr. Anthony S. Fauci, President Biden’s chief medical adviser, has warned in recent days that the country could see a significant increase in infections in the coming weeks. But he said hospitalization rates are unlikely to increase in tandem because many Americans have some degree of immunity, either to vaccines or to previous infections.

Several hundred children aged 5 to 11 have died from Covid since the pandemic began, according to the Centers for Disease Control and Prevention, but pediatric injections have been a tough sell for many parents. Only about 28% of children in this age group received two doses and would be eligible for a booster. About 7% received only one dose, according to agency data.

There was an initial rush for vaccines after they were first offered for this age group in November, but the increase in vaccination rates then slowed.

Dr Edwards said some parents believe the chances of their children becoming seriously ill are low, when vaccines are unknown. She said some research indicates that 45% of infected children show no symptoms.

“The problem is that we can’t predict who will get sick and who won’t,” she said. And among those who do, “there will be children who will be hospitalized, and there will be some deaths”.

The proportion of children aged 5 to 11 who received at least one dose varies greatly from one region to another, according to a study by the Kaiser Family Foundation. Five of the 10 states with the highest vaccination rates were in New England, while eight of the 10 states with the lowest rates were in the South.

The study carried out by researchers from New York, released at the end of Februaryfound that for children aged 5 to 11 years, the effectiveness of the Pfizer vaccine against infection fell to 12% from 68% within 28 to 34 days of the second dose. This was a steeper drop than for older teens and teens who received a much higher dose. .

Another CDC study said two doses of Pfizer reduced the risk of Omicron infection by 31% in 5- to 11-year-olds, compared with a 59% reduction in risk in 12- to 15-year-olds.

The Pfizer vaccine is currently the only one authorized for children under 18.


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