This vaccine did previously have emergency approval by the FDA for use but can now be marketed in the U.S. for use, the letter said.

After a six-week delay, the US Food and Drug Administration has approved Novavax’s Covid-19 vaccine, according to a letter from the agency, but only for people 65 and older and those 12 and up who have at least one underlying condition that puts them at higher risk of severe illness.

WASHINGTON — Robert F. Kennedy Jr. clinched the political support needed to become the nation’s top health official by pledging to work within the decades-old federal system for approval and use of vaccines. Yet his regulators are promising big changes that cloud the outlook for what shots might even be available.

The rising coronavirus cases once again in many parts of the world, especially in Asian countries (such as Hong Kong and Singapore), have raised concerns for health experts. Recent reports show that there has been a sharp increase in coronavirus cases here for the last few weeks.

The head of the Food and Drug Administration said the agency will soon unveil a new framework detailing what companies must do to seek approval of vaccines, a move that comes as the Trump administration has introduced uncertainty into the annual process for green-lighting updated coronavirus shots traditionally offered in the fall.

The GOP-led House Judiciary Committee is requesting records from Pfizer’s CEO and an interview with a former company executive to investigate an allegation that clinical testing related to the development of the company’s Covid-19 vaccine was purposefully delayed until after the 2020 presidential election.