[ad_1]
The coronavirus vaccine made by Johnson & Johnson is much less effective against the Delta and Lambda variants than against the original virus, according to a new study published online Tuesday.
Although disturbing, the results are the result of experiments conducted with blood samples in the laboratory and may not reflect the performance of the vaccine in the real world. But the findings add to the evidence that the 13 million people inoculated with J. & J. The vaccine may need to be given a second dose – ideally one of the mRNA vaccines made by Pfizer-BioNTech or Moderna, the authors said.
The findings contradict those of smaller studies published by Johnson & Johnson earlier this month suggesting that a single dose of the vaccine is effective against the variant even eight months after inoculation.
The new study has not yet been peer reviewed or published in a scientific journal. But this dovetails with observations that a single dose of the AstraZeneca vaccine – which has a similar architecture to the J. & J. vaccine – only shows about 33 percent effectiveness against symptomatic disease caused by the Delta variant.
“The message we wanted to get across was not that people shouldn’t be getting the J. & J. vaccine, but we hope that in the future it will be boosted with another dose of J. & J. or a boost with Pfizer or Moderna, ”said Nathaniel Landau, a virologist at NYU’s Grossman School of Medicine, who led the study.
Other experts said the results were what they expected, as all vaccines seem to work best when given in two doses. “I have always thought, and have often said, that the J. & J. The vaccine is a two-dose vaccine, ”said John Moore, a virologist at Weill Cornell Medicine in New York City.
Dr Moore pointed to several studies in monkeys and people that showed greater effectiveness with two doses of J. & J. one-dose vaccine. He said the new study was particularly credible because it was published by a team unrelated to any of the vaccine makers.
But the data from the new study “doesn’t speak to the full nature of immune protection,” said Seema Kumar, spokesperson for J. & J. Company-sponsored studies indicate that the vaccine “generated strong and persistent activity against the rapidly spreading Delta variant,” she said.
The Delta variant is the most contagious version of the coronavirus to date. It accounts for 83% of infections in the United States, Dr Rochelle Walensky, director of the Centers for Disease Control and Prevention, said in a Senate hearing on Tuesday.
The variant may also be primarily responsible for a recent increase in infections: although they are still low compared to last winter, cases are increasing in all 50 states and hospitalizations are increasing in almost all. In the two weeks ending Tuesday, the country recorded an average of 268 deaths per day.
Delta may cause more breakthrough infections than previous forms of the virus, but more than 99% of hospitalizations and deaths occur in unvaccinated people. Vaccination rates in the country have stalled, with just under 60% of adults fully protected against the virus.
Several studies have suggested that mRNA vaccines made by Pfizer-BioNTech and Moderna would retain their efficacy against the coronavirus, including all variants identified so far. A recent study showed, for example, that vaccines trigger a persistent immune response in the body that can protect against the coronavirus for years.
But the evidence on the J. & J. vaccine was limited because it was deployed later than mRNA vaccines. Most studies on the effectiveness of coronavirus vaccines have been conducted in medical centers and hospitals that have relied on samples from staff members who have received the mRNA vaccines.
The J. & J. The vaccine has also been the subject of reports of blood clots and a rare neurological syndrome, as well as contamination issues at a manufacturing facility in Baltimore.
Small studies published by researchers affiliated with J. & J. suggested that the vaccine was only slightly less effective against the Delta variant than against the original virus, and that the antibodies stimulated by the vaccine got stronger within eight months.
Dr Landau’s team would likely have seen a similar increase in the potency of the vaccine if they had looked at the data over time, said Dr Dan Barouch, a virologist at Beth Israel Deaconess Medical Center in Boston. Data on the J. & J. The strength of the Delta variant vaccine on day 29 is not significantly different from those reported in his own study, Dr Barouch said.
“Basically I don’t see that there is a mismatch,” he said. “The question is kinetics, it’s not just magnitude, because immune responses are not static over time.” The new study also did not take into account other components of the immune defense, he added.
Dr Landau and his colleagues examined blood samples taken from 17 people who had been immunized with two doses of an mRNA vaccine and 10 people with one dose of J. & J. vaccine.
The J. & J. The vaccine started out with lower efficacy than mRNA vaccines and showed greater decline in efficacy against Delta and Lambda variants. “The lower baseline means what’s left to counter Delta is very weak,” Dr. Moore said. “It’s a big concern.”
Very few vaccines are given in a single dose because the second dose is needed to increase antibody levels, noted Akiko Iwasaki, an immunologist at Yale University. People who have been inoculated with the J. & J. The vaccine “relies on this primary response to maintain high levels of antibodies, which is difficult, especially against the variants,” she said.
Boosting immunity with a second dose should raise antibody levels enough to counteract the variants, she said.
Turning to an mRNA vaccine for the second shot, rather than another J. & J. shot, maybe better: Several studies have shown that combining one dose of AstraZeneca vaccine with one dose of Pfizer-BioNTech or Moderna vaccines stimulates the immune response more effectively than two doses of AstraZeneca.
The Food and Drug Administration has said that “Americans who have been fully vaccinated do not need a booster at this time,” and the agency is unlikely to change its recommendations based on lab studies. But the new data should prompt the FDA to reconsider its recommendations, said Dr Landau: “I hope they read our article and think about it.”
[ad_2]
Source link