According to one, no data on coronavirus vaccines so far provides credible evidence in support of boosters for the general population. Review published on Monday by an international group of scientists, including some at the Food and Drug Administration and the World Health Organization.
The 18 authors include Dr. Philip Krauss and Dr. Marion Gruber, FDA scientists who announced last month that he would be leaving the agency, at least partly because they disagreed with the Biden administration’s push for boosters before federal scientists could review the evidence and make recommendations.
Biden administration proposes vaccine booster eight months later initial shots. But many scientists opposition to the plan, adding that vaccines remain powerfully protective against serious illness and hospitalization. The FDA has a committee of advisors scheduled to meet The figures were reviewed on Friday.
In the new review published in The Lancet, experts said that whatever benefits the boosters provide, will not outweigh the benefits of using those doses to protect the billions of people who live unvaccinated around the world. Boosters may be useful in some people with weakened immune systems, he said, but this is not yet needed for the general population.
Several studies, published by the Centers for Disease Control and Prevention, including three on Friday, suggesting that while efficacy against infection with the delta variant decreases slightly over time, the vaccine remains stable against severe disease in all age groups. Only in adults over the age of 75 do vaccines show some weakness in protection from hospitalization.
The immunity provided by vaccines depends on protection from both antibodies and immune cells. Although antibody levels may decrease over time — and may increase the risk of infection — the body’s memory of the virus remains long-lived.
Experts said the vaccines are slightly less effective than the alpha version against infection with the delta variant, but the virus has not yet evolved to evade sustained responses from immune cells. Eventually a booster may also be needed for the general population if a variant emerges that elicits an immune response.
Experts cautioned that any reports of side effects from booster shots such as heart problems or Guillain-Barré syndrome, along with promoting boosters earlier than needed, could undermine confidence in primary vaccination.
Data from Israel shows that booster doses enhance protection against infection. But this evidence was collected only a week or two after the third dose and may not last over time, experts said.