WASHINGTON – US government scientists reject requests for one-dose regimens for two Covid-19 vaccines designed to be given with two injections, saying there is insufficient evidence that a single dose provides long-term protection.
“It is essential that these vaccines are used as authorized by the FDA to prevent Covid-19 and related hospitalizations and deaths,” Peter Marks, director of the Food and Drug Administration center that oversees vaccines, told The Wall. Street Journal.
The FDA approved a two-dose vaccine regimen from Moderna Inc. late last year..
and a partnership of Pfizer Inc.
and BioNTech SE.
More recently, it approved the use of a single-dose regimen for a Johnson & Johnson vaccine..
Some scientists and lawmakers have called for a switch to a single-dose regimen for all vaccines, citing preliminary studies showing that a single injection can be effective. They argue that switching to a single injection will allow the United States to accelerate the pace of vaccines.
In a letter to Acting Secretary of Health and Human Services Norris Cochran on March 2, seven medical members of Congress urged the department to “consider issuing a revised emergency use authorization as soon as possible” that could lead to to the use of a single dose of the Pfizer and Moderna vaccines. .
“Last week, the US passed a sobering milestone of more than 500,000 COVID-19 related deaths,” read the letter, signed by lawmakers including Rep. Andy Harris (R, MD.) And Rep. Gregory F. Murphy, (R., NC). “These are staggering statistics, and anything we can do to help prevent further tragedy, to further protect the public health and safety of the American people, should be fully employed.”
In interviews, senior government scientists at the FDA and the National Institutes of Health said such a change is unwarranted, saying the evidence used to approve the Pfizer and Moderna vaccines was based on two doses.
These scientists said that one dose may offer short-term protection, but longer-term protection is a question mark.
“I’d be flying blind just by using one dose,” said a senior scientist and adviser to President Biden. “If you’re going to do more than follow the studies shown to the FDA, show me that this one-time effect is long-lasting.”
Another senior US government doctor said that the durability of vaccination is especially important when more resistant Covid strains, including those from the UK and South Africa, appear in the US.
“We think it is better to get people to reach the highest level of immunity possible,” said the doctor.
The doctor added that the pace of vaccines is picking up with Merck’s recent decision to help produce the J&J vaccine.
“Very soon we will have a good supply of vaccines,” said the doctor.
Representatives for Pfizer and Moderna did not immediately respond to requests for comment on Saturday. Pfizer has previously said it has no data on the single-dose approach, and Moderna has previously said that it is not looking into the issue.
Paul A. Offit of the Children’s Hospital of Philadelphia, who served on the FDA advisory panel that recommended the use of the Pfizer and Moderna vaccines, said those clinical trials “found a level of neutralizing antibodies [with one dose] that was significantly less than what they got with two doses. “
FDA advisory panel chair Dr. Arnold Monto also said the two-shot regimen is best for the Pfizer and Moderna vaccines. Dr. Monto, a public health physician at the University of Michigan, emphasized the need for two doses to counteract the Covid variants.
“We have information on a two-dose strategy,” Dr. Monto said. “We need high levels of antibodies at those doses to deal with the variants.”
Others holding firm to similar views in the US government include prominent infectious disease physician Anthony Fauci and Andy Slavitt, the White House’s senior adviser for the Covid response. Slavitt said it would be a mistake for the US government to be persuaded by just one study.
University of Minnesota epidemiologist Michael Osterholm said in testimony Thursday before the Minnesota legislature that the United States should consider delaying second doses so more people can get the first.
“We could vaccinate more than our age group over 65. I think the data will support that it’s actually a very efficient way to do it. “
Two weeks ago, researchers in Israel reported that one dose of the Pfizer vaccine was 85% effective in preventing symptomatic illness 15 to 28 days after inoculation.
In the UK, the government has chosen to expand vaccine supplies by delaying a second dose for up to 12 weeks in an attempt to reach more people.
British researchers released preliminary data in recent days saying that either of the two vaccines, from Pfizer and AstraZeneca PLC, reduced the risk of hospitalization among people over 70 years of age by 80%, compared to people of similar ages without vaccination.
AstraZeneca is still conducting a study of its vaccine in the US, which has not yet obtained clearance from the FDA.
Write to Thomas M. Burton at [email protected]
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