*

FDA leaders say studies need to show evidence of benefit

of

annual shots for healthy adults

*

FDA leaders say 100 million-200 million Americans would

still be

eligible for annual shots

*

FDA leaders say U.S. COVID policy has been more aggressive

than

Europe

(Adds background in paragraphs 4-6, details about new trials in

paragraphs 14-15, AAP response in paragraphs 17-18)

By Michael Erman

NEW YORK, May 20 (Reuters) - The U.S. Food and Drug

Administration on Tuesday said it plans to require new clinical

trials for approval of annual COVID-19 boosters for healthy

Americans under age 65, effectively limiting them to older

adults and those at risk of developing severe illness.

FDA Commissioner Marty Makary and top U.S. vaccines

regulator Vinay Prasad wrote in the New England Journal of

Medicine that the benefit of repeated annual shots for healthy

adults was uncertain after several years of the virus

circulating and vaccines being available.

They also said that the U.S. was an outlier among

high-income nations in recommending yearly shots for healthy

adults.

"At-risk Americans can be reassured that they will be

covered by such approvals. At the same time, we want more

evidence at the U.S. Food and Drug Administration," Prasad told

scientists at the FDA during a livestreamed presentation.

"We want to know more about what these products are doing,

especially as we enter the seventh, eighth and ninth dose," he

said.

Health Secretary Robert F. Kennedy Jr., a long-time vaccine

skeptic whose department oversees the FDA, has been remaking the

U.S. health system to align with President Donald Trump's goal

of dramatically shrinking the federal government. Some 20,000

people have left the department as part of mass layoffs.

Makary and Prasad have been critical of U.S. COVID vaccine

policies and indicated that they were under review.

Jefferies analyst Michael Yee said the new guidance

essentially does not change vaccine policy for older and

high-risk Americans, putting investors at ease.

Shares of COVID-19 vaccine makers Moderna ( MRNA ) were up

7.6% at $28.40, Pfizer ( PFE ) rose 1.9% to $23.45 and U.S. ADRs

of Germany's BioNTech rose 4%. Novavax ( NVAX )

shares were up 1.5% at $7.86.

Pfizer ( PFE ) said it was evaluating the details shared today and

that discussions with the FDA are ongoing. The other companies

did not immediately respond to requests for comment.

Makary and Prasad said they expect the FDA will be able to

approve the boosters for adults over the age of 65 years based

on data from tests that measure immune response in patients.

The shots would also be available for everyone over the age

of six months with one or more issues that put them at high risk

for severe COVID-19 outcomes, they said.

But for healthy people between the ages of six months and 64

years, the FDA expects it would require formal clinical trials

for drugmakers to get approval for annual shots.

Prasad said all the COVID vaccine makers will be asked to

conduct placebo-controlled trials in healthy 50 to 64 year olds

and encouraged to conduct them in very young children.

He said that he does not expect that new trials will be

necessary every year, just when there are major shifts in the

virus.

Vaccine makers have argued that because COVID vaccines have

been changed annually to match the circulating strain of the

virus, new placebo-controlled trials could delay availability of

the shots until after their usefulness has passed.

The American Academy of Pediatrics said it had serious

concerns about the new framework and its potential impact on

insurance coverage.

"Taking away coverage means taking away choice for

families," Dr. Sean O'Leary, chair of the AAP Committee on

Infectious Diseases, said in a statement.

EXPENSIVE TRIALS

Dr. David Boulware, an infectious disease specialist at the

University of Minnesota said the new framework is "quite

reasonable. The really high risk people - over 65, people with

chronic medical conditions - can still get the vaccine," he

said.

Boulware said he believed it was unlikely vaccine makers

will conduct the clinical trials to receive the broader approval

in younger adults, saying it would require large enrollment and

could cost "hundreds of millions of dollars."

Makary and Prasad - both new to the FDA this year - have

been critical in the past of the approval process and the

evidence supporting the necessity of annual COVID-19 shots for

many Americans.

Still, they acknowledged that the 2020 development of the

shots was a major scientific, medical, and regulatory

accomplishment. They also called the measles-mumps-rubella

vaccine a vital immunization and said it had been "clearly

established as safe and highly effective."

Kennedy, who long promoted claims that vaccines are linked

to autism, contrary to scientific evidence, has launched a study

to find the causes of a rise in its prevalence.

COVID vaccines are significant products for drugmakers, even

as uptake has fallen post-pandemic. In 2024, U.S. sales of COVID

boosters, sold primarily by Pfizer ( PFE ) and Moderna ( MRNA ), topped $3.5

billion.

When Novavax's ( NVAX ) shot was approved last week, the FDA limited

its use to older adults and people over the age of 12 with

conditions that put them at risk of severe illness.

According to the U.S. Centers for Disease Control and

Prevention, a wide list of conditions constitutes an additional

risk including obesity, diabetes and heart disease, as well as

behaviors like physical inactivity and substance abuse.

Makary and Prasad said that estimates suggest that some 100

million to 200 million Americans would have access to the annual

shots under these new terms.

The FDA's vaccine advisory committee is scheduled to meet

later this week to discuss which variant of the coronavirus

vaccine makers should target ahead of the COVID inoculation

season this year.