J. & J. Study suggests vaccine may be less effective against Delta

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J. & J. Study suggests vaccine may be less effective against Delta

Johnson & Johnson’s coronavirus vaccine is much less effective against the Delta and Lambda variants than the original virus vaccine, according to New study Posted online on Tuesday.

Although alarming, the results are from experiments with blood samples in the lab, and may not reflect the vaccine’s performance in the real world. But the conclusions add to the evidence that 13 million people vaccinated with J. & J. The vaccine may need to receive a second dose — ideally from one of the mRNA vaccines made by Pfizer-BioNTech or Moderna, the authors said.

The conclusions are inconsistent with those in smaller studies Published by Johnson & Johnson earlier this month that a single dose of the vaccine is Active against the variable Up to eight months after vaccination.

The new study has not yet been reviewed or published in a scientific journal. But he agrees with observations that a single dose of AstraZeneca vaccine – which has a similar structure to J. & J. vaccine – appears only about 33% effectiveness Against accidental diseases caused by the delta variable.

“The message we wanted to get across was not that people shouldn’t get J. & J.. a vaccine, but hopefully it will be boosted in the future with another dose of J. & J. ” said Nathaniel Landau, a virologist at New York University’s Grossman School of Medicine, And who led the study: “Or Enhance Using Pfizer or Moderna.”

Other experts said the results are what they were expecting, because all vaccines appear to work best when given in two doses. “I’ve always thought, and often said, that J. & J. A virologist at Weill Cornell Medicine in New York, J. Moore, said, ‘A vaccine is a two-dose vaccine,'” said John Moore, a virologist at Weill Cornell Medicine in New York.

Dr. Moore referred to several studies in monkeys And the Persons that showed Greater Efficiency Two doses of a J. & J. Vaccine, compared to a single dose. He said the new study was particularly credible because it was published by a team unrelated to any of the vaccine manufacturers.

Seema Kumar, a spokeswoman for J&J, said the data from the new study “doesn’t speak to the full nature of immune protection.” She said company-sponsored studies indicate that the vaccine “generated strong and sustained activity against the rapidly spreading delta variant.”

The delta variant is the most contagious version of the coronavirus, which accounts for 83 percent of infections in the United States, said Dr. Rochelle Walinsky, director of the Centers for Disease Control and Prevention, at a Senate hearing Tuesday.

The variable may be primarily responsible for a file last rise In infections: Although still low compared to last winter, cases are on the rise in all 50 states, and hospitalizations are increasing in almost all of these states. In the two weeks to Tuesday, the country averaged 268 deaths per day.

Delta may cause more breakthrough infections than previous forms of the virus, but more than 99 percent of hospitalizations and deaths occur among unvaccinated people. Immunization rates have stalled in the country, with less than 60 percent of adults fully protected from the virus.

Several studies have indicated that mRNA vaccines made by Pfizer-BioNTech and Moderna will maintain their efficacy against the coronavirus, including all variants identified so far. One recent study showed, for example, that vaccines trigger a permanent immune reaction in the body that may occur Protection against corona virus for years.

But the evidence for J. & J. vaccine has been limited, because it was introduced later than mRNA vaccines. Most studies of the effectiveness of coronavirus vaccines have been conducted in medical centers and hospitals that relied on samples from employees who received mRNA vaccines.

J. & J. Vaccine is also prepared by thromboembolism reports and rare neurological syndrome, as well as problems radioactive contamination At a factory in Baltimore.

Small studies published by researchers affiliated with J. & J. suggested that the vaccine was slightly less effective against the delta variant than the original virus, and that the vaccine-stimulated antibodies grew in strength over eight months.

Dr. Dan Baruch, a virologist at Beth Israel Deaconess Medical Center in Boston, said Dr. Landau’s team might have seen a similar increase in the vaccine’s efficacy if they looked at the data over time. Data on J. & J. Dr. Baruch said the potency of the vaccine against the delta variant on day 29 is not much different from that reported in his own study.

“Basically, I don’t see any disagreement,” he said. “The question is about kinetics, it’s not just size, because immune responses are not constant over time.” He added that the new study did not take into account other components of immune defense.

Dr. Landau and colleagues looked at blood samples from 17 people immunized with two doses of the mRNA vaccine and 10 people with a single dose of J. & J. serum.

J. & J. The vaccine started with lower efficacy than mRNA vaccines and showed a greater reduction in efficacy against the Delta and Lambda variants. “The lower baseline means that what is left to meet the delta is very weak,” Dr. Moore said. “This is a major concern.”

Akiko Iwasaki, an immunologist at Yale University, noted that very few vaccines are given as a single dose, because the second dose is necessary to raise antibody levels. People who have been vaccinated with J. & J. The vaccine “relies on that initial response to maintain high levels of antibodies, which is difficult, especially against variants,” she said.

Boosting immunity with a second dose, she said, should raise antibody levels enough to counteract the variables.

Switching to the mRNA vaccine in the second shot, rather than the J. & J. syringe, might be better: Several studies have shown that combining a single dose of AstraZeneca vaccine with a dose of Pfizer-BioNTech or modern Vaccines kicks The immune response More effective than two doses of AstraZeneca.

The FDA said that “fully vaccinated Americans do not need a booster dose at this time,” and the agency is unlikely to change its recommendations based on lab studies. But the new data should prompt the Food and Drug Administration to reconsider its recommendations, Dr. Landau said, “I hope they read and think about our paper.”

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