Edith Arangoitia, 46, (who came along with her elderly mother) is vaccinated with the Pfizer-BioNTech Covid-19 vaccine by Dr. Galen Harnden at The Collaborative in Chelsea, Massachusetts on February 16, 2021.
Joseph Prezioso | AFP | fake images
White House chief medical adviser Dr. Anthony Fauci said Monday that Americans should continue to receive two doses of the Pfizer and Moderna Covid-19 vaccines, despite a recent study in the United States that showed that the injections are highly effective after just one dose.
A Centers for Disease Control and Prevention study published last week found that a single dose of Pfizer or Moderna’s Covid-19 vaccine was 80% effective in preventing coronavirus infections among caregivers. medical and other essential workers. Two doses are better than one, federal health officials said, adding that the effectiveness of the vaccines rose to 90% two weeks after the second dose.
While the 80% figure was great news, Fauci said Monday that he is still concerned about the duration of protection after a single dose, especially with the emergence of highly contagious variants that have shown the ability to evade protection from vaccines.
“When you look at the level of protection after a dose, you can say that it is 80%, but it is a little weak 80%,” Fauci said during a press conference at the White House on the pandemic. “When you leave it in a dose, the question is how long does it last?”
Highly infectious Covid-19 variants that have shown some resistance to vaccines also pose a challenge, Fauci said. “You’re in a weak zone if you don’t have the full impact” of two doses, he said.
Fauci’s comments come as some health experts and public health officials argue that the US should prioritize giving Americans only one dose of the vaccines before moving on to second doses, accelerating the pace of vaccines. in all the country.
Unlike the Johnson & Johnson vaccine, which requires one dose, the Pfizer and Moderna vaccines require two injections three to four weeks apart. In the UK, health officials decided to extend the time between the first and second doses to 12 weeks in an effort to speed up vaccinations.
Fauci has said repeatedly in recent months that the United States should stick to the two-dose regimen.
Dr. Paul Offit, a voting member of the FDA’s Vaccines and Related Biologics Advisory Committee that reviewed both the Pfizer and Moderna vaccines for emergency use authorization, told CNBC last week that the studies have shown that immunity appears to be “longer lasting” after the second dose, meaning that protection may last longer.
The two-dose vaccine regimen also produces 10 times the amount of neutralizing antibodies, which play an important role in fighting the virus, from the first to the second dose, Offit told CNBC.
Second, and more importantly, the scientists also detected the so-called T cells after the second dose, another important part of the immune response that generally provides longer-lasting immunity, he said.
Fauci said Monday that he “respects” the arguments for a single-dose strategy, but added that the United States currently has sufficient doses to provide the first and second doses to Americans. “Although we always keep an open mind, we consider that the route we are on is the best route,” he said.