WASHINGTON – US government scientists oppose calls for single-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 approved by the FDA to prevent Covid-19 and related hospitalizations and death,” Peter Marks, director of the Food and Drug Administration’s center that monitors vaccines, told The Wall. Street Journal.
The FDA approved a two-dose regimen for Moderna Inc. vaccines late last year. good
and from 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 one injection can be effective. They argue that shifting to one shot will allow the US to accelerate the pace of vaccinations.
In a letter to Acting Secretary of Health and Human Services Norris Cochran on March 2, seven physician members of Congress urged the department to “issue a revised emergency permit as soon as possible” which could lead to the use of a single dose of Pfizer and Moderna vaccines.
“Last week, the US passed a sobering milestone of more than 500,000 deaths related to COVID-19,” said 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 – must be fully exploited.”
In interviews, senior government scientists at the FDA and the National Institutes of Health said no such shift is warranted, saying the evidence used to approve the Pfizer and Moderna vaccines was based on two doses.
These scientists said that one dose can provide short-term protection, but the longer-term protection is a question mark.
“You would fly blind if you use just one dose,” said a senior scientist and adviser to President Biden. “If you’re going to do anything other than follow the studies shown to the FDA, show me that this one-time effect is sustainable.”
Another senior US government physician said vaccination durability is especially important when more resistant strains of Covid, including those from the UK and South Africa, appear in the US.
“We think it is best to give people the highest level of immunity possible,” said the doctor.
The doctor added that the pace of vaccinations is picking up with Merck’s recent decision to help produce the J&J vaccine.
“We will have a good supply of vaccines very soon,” said the doctor.
Representatives from 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 it is not studying the problem.
Paul A. Offit of Children’s Hospital in Philadelphia, who was on the FDA advisory panel recommending the use of the Pfizer and Moderna vaccines, said those clinical studies “found a level of neutralizing antibodies. [with one dose] that was considerably less than what they got with two doses. “
The chair of the FDA advisory panel, 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, stressed the need for two doses to counteract the Covid variants.
“We have information on a two-dose strategy,” said Dr. Monto. “We need high antibody levels at those doses to deal with the variants.”
Others holding similar views in the US government include prominent infectious disease physician Anthony Fauci and Andy Slavitt, a senior White House adviser on Covid’s response. Mr. Slavitt said it would be a mistake if the US government were convinced by just one study.
University of Minnesota epidemiologist Michael Osterholm said in testimony to the Minnesota legislature on Thursday that the US should consider delaying the second dose so that more people can get the first shots.
“We could vaccinate more of our over-65s. I think the data will support that this is actually a very effective way to go. “
Two weeks ago, researchers in Israel reported that a single 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 the vaccine supply by delaying a second dose for up to 12 weeks in order to reach more people.
British researchers released preliminary data in recent days saying that one of the two vaccines – from Pfizer and AstraZeneca PLC – reduced the risk of hospitalization in people over 70 years old by 80%, compared to people of comparable ages without vaccination.
AstraZeneca is still conducting a US investigation of its vaccine, which has not yet received FDA approval.
Write to Thomas M. Burton at [email protected]
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