TUESDAY, July 12, 2022 (HealthDay News) -- The White House is weighing whether to offer a second COVID booster shot to American adults under 50.

The new push comes in response to the latest, highly contagious Omicron variants, which have increased hospitalization rates and raised new concerns about waning immunity in people who were vaccinated six or more months ago.

Expanding eligibility requirements for a fourth dose of the vaccine would require regulatory approval. Discussions with both the U.S. Food and Drug Administration and the U.S. Centers for Disease Control and Prevention are slated for the near future, The New York Times reported.

In March, the U.S. Food and Drug Administration approved second booster shots for adults 50 and older, along with immunocompromised young adults. But Dr. Anthony Fauci, White House chief medical adviser, has forcefully argued that all younger adults should be eligible for a second booster.

Dr. Ashkish Jha, the White House coordinator for the pandemic response, is also in favor of the approach, the Times reported.

In an interview on Monday, Fauci said that while the clinical data to support a second booster shot for those under age 50 is not there, many in this age group got their last booster shot six or more months ago, and that their immunity is likely dwindling.

The final decision is up to the FDA and the CDC, but Fauci said, “I think there should be flexibility and permissiveness in at least allowing” a second booster for younger adults.

But others in the federal government are still waiting on more data to justify the decision, the Times reported. Some argue that the White House isn't working hard enough to persuade Americans to accept the original round of COVID-19 vaccines, rather than pushing to boost immunity among groups that have already received at least one dose and are more protected.

Others worry that in the attempt to promote booster shots now, new Omicron-specific booster shots will be a tough sell in the fall. On June 28, the FDA recommended that the vaccines be redesigned for the latest fast-spreading Omicron variants of the disease, BA.4 and BA.5. As of July 2, the variants accounted for just over 70% of all U.S. infections.

Some experts have cautioned against a second booster shot for more Americans for different reasons.

Paul Offit, director of the Vaccine Education Center at the Children’s Hospital of Philadelphia and a member of the FDA's vaccine advisory panel, has criticized federal officials for what he has called “booster mania.”

“I do think [a second booster shot] does make sense for certain groups, but a universal boosting strategy doesn’t make sense,” Offit told the Washington Post on Monday, citing data showing that three doses of an mRNA vaccine provided long-lasting protection against severe disease.

“At some level, we’re going to have to get used to mild illness and moderate illness as part of this virus -- which is going to be with us for the rest of my life, the rest of my children’s lives, the rest of their children’s lives," he said.

But there's another potential problem: Offit warned that repeatedly administering the same vaccine could lead to a phenomenon known as “imprinting,” where a person's immune system develops a highly targeted response to earlier versions of a virus and fails to adapt to new variants.

“As you continue to boost with the same ancestral strain, you lock yourself into that response,” Offit explained. “Should there ever be a virus that is truly resistant to protection against serious illness … you need to start all over again and give that vaccine.”

The White House plans to hold a briefing Tuesday on the threats posed by the new variants, which have driven up hospitalization and death rates in Britain, France, Portugal, Belgium and Israel, the Times reported. Still, rates fall far below those seen last winter when the original Omicron variant took over the world.

More information

For the latest on the availability of booster shots, check out the U.S. Centers for Disease Control and Prevention.

SOURCE: The New York Times; Washington Post