A seasonal COVID-19 booster shot? Don't count on it in the US or Europe

People in the U.S. and Europe hoping to receive COVID-19 vaccine booster shots every four to six months are in for a rude awakening.

On Wednesday, experts on both sides of the Atlantic tossed cold water on the idea of seasonal boosting.

In Europe, regulators concluded that it is too early to consider allowing a fourth dose of the Pfizer-BioNTech or Moderna vaccine. Meanwhile in the U.S., a panel of experts has directed the FDA to devise a plan for annual boosting against COVID-19.

The advice comes just a week after the FDA signed off on allowing people 50 and older to receive a fourth dose of Pfizer’s Comirnaty or Moderna’s Spikevax and suggested a fifth dose may be on its way by the fall.

The measure was designed to get ahead of a potential next surge of the virus. But even among experts, there is much uncertainty about future threat of the disease.

Trevor Bedford, Ph.D., of the Fred Hutchinson Cancer Research Center told the FDA panel Wednesday that a new strain such as omicron could emerge every 18 months to 10 years.

The mixed messages in the U.S. are bound to fuel further distrust in the vaccines and the regulators. Many in the U.S. are not sold on a first booster dose. As of March 30, of the 217.6 million Americans who had been fully vaccinated, only 97.5 million had received a booster.

Across the Atlantic, the European Centre for Disease Prevention and Control and the European Medicines Agency concluded that there is no evidence of a clear benefit of a fourth dose of the mRNA vaccines and that it should be provided only to those 80 and older and others who are immunocompromised.

The European experts did not rule out the possibility of signing off on a booster dose in the fall.

In making their assessments, experts in U.S. and Europe are relying on data from Israel which show that a fourth dose can significantly reduce the risk of severe disease but that protection from infection wanes within several weeks.

“Data indicate that a second booster given at least four months after first booster restores antibody levels without raising any new safety concerns,” the European regulators said in a statement. “Data also suggest that a second booster provides additional protection against severe disease, although the duration of the benefits is not yet known.”

Meanwhile, analysts at Cantor Fitzgerald suggested that current boosting discussions bode well for the durability of the demand for Pfizer and Moderna vaccines.

“We believe that the FDA's prioritization of staying ahead of future variants/outbreaks and interest in coordinating efforts with manufacturers in a unified approach on future vaccine strain recommendations are positives for more flexible, adaptive technologies like mRNA,” Cantor Fitzgerald analyst Louise Chen wrote to clients.