Investing.com -- Shares of vaccine makers saw an uptick in the latest trading session, with Moderna Inc (BMV: MRNA ). (NASDAQ: MRNA ) leading the rally with an 11% surge, followed by BioNTech (NASDAQ: BNTX ) climbing 4.5%, Novavax Inc. (NASDAQ: NVAX ) increasing by 2.7%, and Pfizer Inc. (NYSE: PFE ) rising 1.75%. The upward movement comes after the U.S. Food and Drug Administration (FDA) indicated it would require new clinical trials for the approval of annual COVID-19 boosters for healthy Americans under 65, easing concerns about the potential withdrawal of these vaccines from the market.

The FDA’s announcement, made public on Tuesday, outlined that while the availability of annual boosters this fall would be limited to older adults and those at higher risk of severe illness, they would still be accessible to a significant portion of the population. FDA Commissioner Marty Makary and top U.S. vaccines regulator Vinay Prasad expressed their anticipation that the FDA will be able to approve the boosters for adults over 65 years of age based on current immune response data.

Furthermore, the vaccines would remain available for individuals over six months of age with risk factors that increase their likelihood of severe COVID-19 outcomes. However, for healthy individuals between six months and 64 years, the FDA expects randomized, controlled trials to be necessary for annual shot approvals, with saline potentially used as a placebo in these trials.

The expectation of new trials has been met with optimism, as it suggests a continued demand for COVID-19 vaccines and booster shots. Vaccine manufacturers had previously argued that new placebo-controlled trials might delay the shots’ availability, but FDA officials contend that these studies are essential to ensure that annual vaccinations for healthy younger Americans are evidence-based. The FDA’s stance aims to generate much-needed evidence, addressing uncertainties about the benefits of repeated doses for individuals with previous COVID-19 infections and vaccinations.