Fauci sets the record for one or two doses of Pfizer, Moderna vaccines

(CNN) – The United States firmly maintains its strategy of administering two doses of Moderna and Pfizer / BioNTech Covid-19 vaccines a few weeks away. However, the idea of ​​expanding the offer by distributing a single dose did not disappear.

Trump administration general surgeon Dr. Jerome Adams said in a tweet on Tuesdayy that good protection available with a single blow “is better than excellent protection for a few”.

He later clarified in a second tweet that he did not recommend 100% coverage, but that it was “worthwhile to give states the flexibility to try.”

Although 80.5 million doses of vaccine have been administered in the United States and Johnson & Johnson single-dose vaccine is on offer in the United States, demand far exceeds the number of vaccines available.

This did not cause vaccine manufacturers, the US Food and Drug Administration or the CDC to move to single doses to cover more people earlier.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, told CNE Erin Burnett on Wednesday that Adams’ tweets do not take into account the impact of virus variants, which can reduce the amount of protection against vaccines.

“First of all, I love Jerome Adams. He really is a great guy. We worked so well together during the Trump administration, “Fauci said. “I don’t think it’s fair in that regard.”

Going with a single dose, “you are at a very low level. Good enough to make protection, but if you cut it five times, you fall off the protection diagram. ”

MRNA vaccines have been approved for use in the United States based on clinical trials showing that two doses of vaccines taken a few weeks apart are approximately 95% effective in preventing symptomatic infection. Clinical studies for both vaccines show that the second dose gives a great boost to protective antibodies.

CDC guidelines continue to recommend two doses of Pfizer and Moderna vaccines, and experts at Monday’s meeting of the CDC Advisory Committee on Immunization Practices (ACIP) said there was not enough scientific evidence to support a vaccination strategy that would delay a second dose or would eliminate it all together.

Five studies have shown that delaying the second dose of mRNA may leave some people less protected against SARS-Cov-2 variants, said CDC Dr. Heather Scobie at the ACIP meeting.

Fauci told The Washington Post this week that there were “risks on both sides” of switching to a single dose or staying with both. Experts worry that a single-dose strategy could lead to more than one variant of coronavirus and could create more doubts and confusion during the already complicated launch of the vaccine.

“It simply came to our notice then [two shots] is that what you should do … and then we say, “Oops, we changed our minds”? Said Fauci. “I think that would be a messaging challenge, to say the least.”

This does not mean that no dosage changes will follow.

Researchers around the world are analyzing the effectiveness of single doses of mRNA vaccines. Meanwhile, the J&J vaccine – currently licensed as a single-dose vaccine – is also being tested as two doses to see if it will provide more protection.

Study of single doses

Some countries are already using single-dose strategies as a way to expand their offer and provide some protection to more people.

Since the end of December, the UK has not told people to give up the second shot, but has delayed the second dose of Pfizer / BioNTech vaccine to give priority to the first doses. The delay meant that the dose interval could be extended to 12 weeks instead of about three.

In response to the change in the vaccination program, Pfizer said at the time that it had not tested its vaccine in this way.

The Pfizer and BioNTech Phase 3 study for the Covid-19 vaccine was designed to evaluate the safety and efficacy of the vaccine following a 2-day, 21-day separate program, Pfizer said. “There is no evidence that protection after the first dose is sustained after 21 days.”

There has been some research to suggest that the Pfizer / BioNTech vaccine offers some protection after a single dose.

Researchers at Israel’s largest hospital analyzed what happened after 7,000 employees were vaccinated with the first dose of Pfizer / BioNTech vaccine. In the second to fourth week after receiving the first blow, the rates of symptomatic infection decreased by 85%.

However, it is still unclear how long this protection will last. The study also noted that people who were vaccinated were “younger and healthier” and may not reflect the wider population.

There is also some research that suggests that one dose may be enough for people with a previous infection. Two papers published last week in The Lancet found that just one dose of Pfizer / BioNTech coronavirus vaccine could induce a strong enough immune response in people who already had the coronavirus that could protect them from future infections. France has already recommended that previously infected people receive a single dose.