Vaccine stocks surged in morning trading. Moderna rose 11%, BioNTech SE rose 5%, Novavax rose 3%, Novo Nordisk, Pfizer, and Regeneron Pharmaceuticals rose 2%.

Members of the World Health Organization adopted an agreement on Tuesday intended to improve preparedness for future pandemics following the disjointed global response to COVID-19, but the absence of the U.S. cast doubt on the treaty's effectiveness.

US regulators will no longer approve booster shots to prevent Covid infections for healthy adults and children without new clinical trials showing they are still safe and effective, adding a costly new requirement that could ultimately limit who gets the vaccines.

Advisers to the U.S. Food and Drug Administration will discuss whether to recommend COVID-19 vaccines for 2025-26 for targeting the LP.8.1 subvariant, documents filed on Tuesday showed.

The LP.8.1 strain has begun spreading at a faster rate than other variants. It has already become dominant in different parts of the world such as the United States and is spreading in Europe.

Food and Drug Administration Commissioner Marty Makary and Vinay Prasad, who leads the agency’s vaccine division, outlined the approach the agency intends to take with the Covid shots in an article published Tuesday in the New England Journal of Medicine.

Typically, with seasonal vaccines like the flu and Covid, drugmakers are able to introduce new formulas designed to match the mutating virus based on simple tests that show they generate a strong immune response, rather than repeated clinical trials.