WASHINGTON (BLOOMBERG) - Medical experts who advise US regulators on vaccines are chafing at what they perceive as political interference in the review process by the Biden administration.
Last month, the White House announced plans to begin distributing Covid-19 booster shots to Americans on Sept 20. However, the effort still needs the Food and Drug Administration and the Centres for Disease Control and Prevention to sign off.
Members of a key panel that advises the CDC on vaccines have pushed back consideration of the plan to mid-September and said this week they were concerned that politics was getting ahead of the process.
It's "very frightening to me that healthcare providers are trying to do the best job that they can, and are taking guidance from HHS and the White House". said Helen Talbot, a Vanderbilt University professor of medicine and member of the CDC's Advisory Committee on Immunisation Practices, in a meeting on Monday (Aug 30).
Some short-term data from Israel supports the use of booster shots. Yet the public push by the White House to get a rollout underway has raised concerns the administration is rushing ahead without enough data and regulatory oversight, said Paul Offit, director of the Vaccine Education Centre at the Children's Hospital of Philadelphia.
Meanwhile, European health authorities said there's no urgent need for wide use of boosters, although some countries are offering them.
"I would be very surprised if the CDC recommended a third dose of the vaccine to the general population," said Offit, a former member of the CDC's advisory panel of outside experts that evaluates vaccine data for the agency.
The committee originally planned to evaluate boosters at an Aug 24 meeting that was postponed to Monday and delayed again to the middle of this month.
Rather than an expected vote on the shots Monday, CDC's Sara Oliver briefly set out guidelines for considering boosters, making clear that current vaccine regimens are safe and prevent hospitalisations and deaths.
Biden first described the booster plan in a statement signed by the top health professionals, including Walensky, medical adviser Anthony Fauci and FDA Acting Commissioner Janet Woodcock.
"They reviewed mountains and mountains of available data on vaccine effectiveness and made a clinical judgement that boosters would be needed," White House Press Secretary Jen Psaki said on Wednesday, asked about concern that the administration got ahead of the science.
"Our responsibility and our objective is to save more lives, protect more people, and as soon as this data - the science - made clear that boosters would help do that, we wanted to put that information out to the public."
The plan is for people to get boosters eight months after their second shots of either Pfizer or Moderna vaccine, which would put older people and health workers first in line. That would also defer boosters for younger, healthier adults - and debate over whether they should get them - by months.
While the Biden plan calls for boosters for everyone who's received two shots of the messenger RNA vaccines, Oliver's presentation pointed out that risks and benefits will vary by age.
The "policy for booster doses needs to take this benefit/risk balance into account", slides from Oliver's presentation said. It's "critical to wait for additional safety data and regulatory allowance for booster doses".
The FDA has also been under strain and scrutiny as it quickly reviewed Covid-19 vaccines and treatments developed at top speed.
Two top vaccine officials said that they would step down later this year, a possible sign of frustrations with the Covid-19 vaccine effort that began when former president Donald Trump scolded the agency for not working fast enough to approve shots.
Attempts to reach the two officials - Marion Gruber, head of the regulator's Office of Vaccines Research and Review, and Philip Krause, deputy director for the FDA's Center for Biologics Evaluation and Research - were unsuccessful.
Acting FDA Director Janet Woodcock said in an email to staff that she was confident the agency's vaccine evaluators would be able to continue working effectively.
Seen as a potential key step in controlling the coronavirus surge that's been spurred by the delta strain, the need for and effectiveness of boosters are still being debated by public health officials and scientists.
Booster advocates have said that breakthrough infections among the vaccinated show that the standard regimens aren't sufficient to stop the spread of Delta.
Booster shots have already begun in some communities. Almost a million Americans have received an additional vaccine dose since Aug 13, according to CDC data.
It's unclear how many of those doses went to those with weak immune systems, for whom extra shots have already been recommended by the FDA and CDC.
William Schaffner, a Vanderbilt University infectious disease expert and non-voting ACIP member, said his internist is already giving out boosters to those over 70 on the basis of the White House statement.
New York Governor Kathy Hochul has already pledged US$65 million for local communities to set up facilities to administer Covid-19 booster shots when they are approved.
But the vaccine panel is still waiting for more data to determine the best booster dose approach, said Camille Kotton, a CDC vaccine adviser.
For now, the majority of vaccinated Americans are well protected against severe disease, despite the delta variant's potency, said Kotton, who's also clinical director of transplant and immunocompromised host infectious diseases at Massachusetts General Hospital in Boston.
Hospitalisation rates, rather than just symptomatic infections, are likely to be a key factor in deciding how to roll out the extra doses, said Linda Eckert, a non-voting liaison to ACIP and professor of obstetrics and gynaecology at the University of Washington in Seattle.
However, hospitalisation rates among most groups haven't changed since the Delta variant arose, she said.
During the Tuesday briefing, Walensky acknowledged that while data reviewed by the CDC advisers was currently insufficient, she was confident that there would be enough to support a recommendation prior to the start of the booster plan.
The panel "did not review international data that actually has led us to be even more concerned about increased risk of vaccine effectiveness waning against hospitalisations, severe disease and death - they will be reviewing that as well", she said.