An expert review of scientific evidence to date has concluded that Covid-19 vaccine booster shots are not needed at this time for the general public, a group of leading U.S. and international scientists said Monday in the peer-reviewed journal The Lancet.
The conclusion by scientists, including two senior Food and Drug Administration officials and the WHO, came as studies continue to show the authorized Covid vaccines in the U.S. remain highly effective against severe disease and hospitalization caused by the fast-spreading delta variant.
While Covid vaccine effectiveness against mild disease may wane over time, protection against severe disease may persist, the scientists said. That’s because the body’s immune system is complex, they said, and has other defenses besides antibodies that may protect someone from getting seriously sick.
“Current evidence does not, therefore, appear to show a need for boosting in the general population, in which efficacy against severe disease remains high,” the scientists wrote, adding the wide distribution of boosters is “not appropriate at this stage in the pandemic.”
They acknowledged that booster shots may eventually be needed for the general population if vaccine-induced immunity wanes even further or a new variant emerges that can evade the protection of the shots.
They said there are risks to distributing boosters too soon, including the potential for side effects such as a rare heart inflammation condition known as myocarditis, which is more common after the second dose of mRNA vaccines.
“If unnecessary boosting causes significant adverse reactions, there could be implications for vaccine acceptance that go beyond COVID-19 vaccines,” they wrote.
The comments come a week before the Biden administration says it plans to begin offering Covid vaccine booster shots to the general public. An FDA advisory group is meeting Friday to discuss the data to support the wide use of boosters.
The administration last month cited three new studies, released by the Centers for Disease Control and Prevention, that showed their protection against Covid diminished over several months. The administration’s plan, outlined by senior health officials, calls for a third dose eight months after people get their second shot of either the Pfizer or Moderna vaccines.
Scientists and other health experts have repeatedly criticized the plan, saying data they cited wasn’t compelling, characterizing the administration’s push for boosters as premature.
The scientists in The Lancet review published Monday include Marion Gruber, director of the FDA’s Office of Vaccines Research & Review, and deputy director Phil Krause. Both officials are departing the FDA this year after they were reportedly frustrated over the agency’s decision to support booster shots.
The scientists said boosting could be appropriate for some individuals, such as those with weakened immune systems, who don’t produce an adequate immune response after receiving two doses of a vaccine.
Federal health officials last month authorized booster shots for such people including cancer and HIV patients or those who have had organ transplants.