VRBPAC members were alerted that the meeting was canceled in an email from the FDA that did not include an explanation, according to the Washington Post. The cancelation is raising concerns that the timing and availability of next season's flu shot could be affected.

The U.S. Food and Drug Administration confirmed on Thursday that a meeting of its independent advisory panel to discuss the composition of this year's flu vaccine has been canceled and the regulator would instead make recommendations later.

The Food and Drug Administration unexpectedly canceled an annual meeting of its advisers to update next season's influenza vaccines, an adviser on the panel and multiple officials tell CBS News, upending the usual process to start manufacturing next winter's flu shots.