The Food and Drug Administration signed off on updated COVID-19 vaccine and booster shots Monday, moving one step closer to making the new shots available for the public to get boosted for the fall virus season. The decision comes amid an increase in COVID hospitalizations and concern about the spread of several new variants. 

"The public can be assured that these updated vaccines have met the agency's rigorous scientific standards for safety, effectiveness, and manufacturing quality. We very much encourage those who are eligible to consider getting vaccinated," Dr. Peter Marks, director of FDA's Center for Biologics Evaluation and Research, said in a news release announcing the move. 

The FDA said it would greenlight the updated vaccines for Americans as young as 6 months old from Moderna and Pfizer. 

However, like with other vaccines, most vaccinations will not be available until after a panel of the Centers for Disease Control and Prevention's outside vaccine advisers also weighs in on new recommendations. The CDC's Advisory Committee on Immunization Practices is scheduled to vote Tuesday afternoon on the updated shots. 

"We expect this season's vaccine to be available in the coming days, pending recommendation from public health authorities, so people can ask their doctor about receiving their COVID-19 vaccine during the same appointment as their annual flu shot," Albert Bourla, chairman and CEO at Pfizer, said in a statement.

The new shots are similar to previously approved formulas but were updated to target the XBB variants — strains of the virus descended from the original Omicron variant — which became dominant last winter. 

Newer descendant strains have since emerged, though vaccine makers have announced early findings suggesting their shots will also work for the latest strains on the rise, including BA.2.86. 

"The upcoming, updated COVID booster shots still provide the best protection we have against the disease, especially the most severe forms of COVID," Emily Smith, a global health expert and author of "The Science of the Good Samaritan," told CBS News in an email. "Even though we continue to have new variants of COVID pop up, the good news is that the updated booster shots still work against the current variants circulating, including the newest variants."

Smith says her whole family, including her children, will get the booster shots when they're available.

"With the recent surge in cases and projected surges this fall, now is the time to get your vaccines," she added.

When will the new COVID booster be available?

Shots from Pfizer and Moderna can begin shipping out this week following the FDA's authorizations and approvals for the revised mRNA vaccines.

Vaccinators have already been pre-ordering doses. The shipments mark the first largely purchased and delivered through the traditional commercial market, instead of the government-bought supplies from earlier in the pandemic.

While the FDA's move also means vaccinators can legally begin offering the shots, most will likely wait until the CDC also weighs in with its recommendations on the revised vaccines. That is a key step to guarantee federal liability protections for vaccinators. 

The Biden administration has said it plans to continue offering its online search portal to find COVID-19 vaccinations. However, for Americans with private insurance, whether their plans cover options on that website may vary between insurers.

A third option is also expected to roll out later this year from Novavax; the company announced last month it was also seeking the FDA's authorization for an update to its COVID vaccine. Pfizer and Moderna had already completed their requests earlier in the summer.

"Novavax is currently responding to the FDA's requests to facilitate final review, and timing is ultimately at the discretion of the FDA," the vaccine maker said in a release Monday.

Are COVID boosters still free?

For Americans with insurance, COVID-19 vaccines will remain free through in-network providers, similar to the annual flu shot.

Under a law passed early in the pandemic, private insurers have been required to cover COVID-19 vaccines "immediately upon the vaccine becoming authorized or approved" by the FDA. This is different than other vaccines, which insurers typically have several months to implement coverage for.

For Medicare, seniors will continue to pay nothing for their COVID-19 vaccinations from any providers that accept Medicare assignment, a Centers for Medicare and Medicaid Services spokesperson said. Medicare Advantage beneficiaries also will also not have to pay anything, as long as they get their shots from an in-network provider.

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For uninsured Americans, the Biden administration aims to offer shots for free through its "Bridge Access Program" at health centers, local health departments and eventually pharmacies.

Who should get the shots?

The FDA says virtually all Americans as young as 6 months old are now approved or authorized to get at least one dose from either Pfizer or Moderna from their updated formulation.

However, while virtually all Americans are now eligible to get the shots, recommendations on when and who it's most important for will be up for the CDC's ACIP to consider on Tuesday.

Not all experts agree on whether everyone should be recommended to get the new shots, or just those at higher risk of severe disease.

John Moore, a professor of microbiology and immunology at Weill Cornell Medical College, told KFF Health News that he saw the new shots as "not remotely a game changer."

For healthier adults and children, "it's a boost in protection for a few months," Moore said.

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