In a major policy change, the Food and Drug Administration has announced a plan to limit access to future COVID-19 shots only to people over 65 years old or those with an underlying health condition.

This change would apply to any future updated versions of the vaccine, a spokesperson at the department of Health and Human Services told ABC News. For the past several years, COVID shots have been updated ahead of the winter respiratory virus season to better match the evolving virus.

But FDA Commissioner Dr. Martin Makary and FDA vaccine head Dr. Vinay Prasad argued this week that annual booster shots are not worth the risk for otherwise healthy people.

The FDA plans to impose these restrictions on future shots for younger, healthy people, unless vaccine makers are willing to pay for newer and and lengthy placebo-controlled trials.

“We are evaluating the details shared today and discussions with the FDA are ongoing,” Pfizer told ABC News in a statement.

“We appreciate the FDA’s clear guidance and remain committed to working with the Agency to provide the data they need to ensure access for Americans,” Moderna told ABC News.

Since the COVID-19 virus can mutate quickly, a lengthy clinical trial may result in a vaccine that no longer protects against currently circulating variants, experts cautioned.

“By the time you finish the trial, the strain that’s out there in the community is probably long gone. So, they’re basically saying, unless you’re in those higher-risk groups, you can forget about getting the COVID vaccine,” former acting CDC director Richard Besser, now president and CEO of the Robert Wood Johnson Foundation, told ABC News.

A spokesperson for HHS, which oversees FDA, told ABC News, “The COVID-19 public health emergency has officially ended, and we are entering a new phase in our response to the virus. A rubber-stamping approach to approving COVID boosters in perpetuity without updated clinical trial data under the Biden administration is now over.”

Last month, more than 300 people died each week from COVID, according to the latest CDC data. Death rates were even higher earlier this year as the virus was spreading, with nearly 1,000 Americans dying weekly in January.

The new policy comes as the FDA’s vaccine committee of independent advisers are set to meet on Thursday to discuss the latest data on vaccine safety and efficacy, including COVID shots. Typically, FDA leadership waits until after hearing the advice of its advisers before implementing a new approval or policy change.

Previously, updated COVID vaccines had been recommended annually by the CDC for everyone over the age of 6 months. The CDC has historically set vaccine recommendations, while the FDA determines which vaccines to authorize or approve after being deemed safe and effective.

“The FDA has kind of usurped the CDC’s recommending capacity. Usually, the FDA is a regulatory body. They say the vaccine can be sold, and the CDC says, ‘Jere’s the groups who should get it,’” Dr. Paul Offit, a vaccine expert at Children’s Hospital of Philadelphia, told ABC News.

Added Besser: “It’s also not something the FDA would normally do. It’s something CDC would do. And so that’s a really important issue here.”

The new COVID vaccine framework would allow an estimated 33% of the U.S. population to be eligible for the shots, or at least 100 million people, FDA officials noted. It matches recommendations from other countries such as the U.K., Canada and Australia.

Experts say there is a real scientific debate about whether annual boosters are necessary for otherwise young and healthy children and younger adults, especially now that most Americans now have some immunity gained from past vaccination and infections.

In mid-April, the CDC’s vaccine committee of independent advisers had discussed whether to keep the recommendation that everyone over 6 months receive an annual COVID vaccine.

Some experts have argued an FDA restriction could create insurmountable barriers for those who no longer qualify but want to get vaccinated anyway to protect vulnerable family members. Officials at the FDA have called for more evidence on whether vaccines prevent transmission before providing that option.

“To date, there is no high-quality evidence that you getting a booster protects your grandma, beyond your grandma getting the booster herself,” Prasad said at an FDA press conference Tuesday. “Does it lead to less transmission? Does it lead to fewer instances of severe disease? Again, we are interested in evidence to inform this claim.”

Insurance coverage of future COVID vaccines will likely be determined based on recommendations from the CDC and the agency’s independent panel of advisers later this summer. A final recommendation on who should be eligible for updated shots will likely come from the CDC director later this year.

Insurance companies will “continue to monitor the forthcoming recommendations and guidance from ACIP and CDC. As of today, there is no change in how plans cover the existing vaccines for the previously recommended populations,” according to AHIP, a national organization representing insurance companies.

“The ultimate goal of the vaccine is to keep people out of the hospital. But people could reasonably say, moderate infections aren’t fun either, so I’m going to choose and get this vaccine,” Offit noted. “I think that’s fine. I think it’s a reasonable choice. I just hope that we’re not restrictive.”