Edith Arangoitia, 46, (who came as a companion to her elderly mother) is vaccinated with the Pfizer-BioNTech Covid-19 vaccine by Dr. Galen Harnden at La Collaborativa in Chelsea, Massachusetts on February 16, 2021.
Joseph Prezioso | AFP | Getty Images
White House Chief Medical Consultant Dr. Anthony Fauci said on 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 injections are highly effective after just one dose.
A study by the Centers for Disease Control and Prevention published last week found that a single dose of Pfizer or Moderna’s Covid-19 vaccine was 80% effective in preventing coronavirus infections among healthcare professionals and other key professionals. Two doses are better than one, federal health officials said, adding that vaccine effectiveness jumped to 90% two weeks after the second dose.
While the 80% figure is great news, Fauci said on 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 escape protection from vaccines.
“When you look at the level of protection after a dose, you can say it is 80%, but it is slightly tenuous 80%,” said Fauci during a press conference at the White House about the pandemic. “When you leave with a dose, the question is how long does it last?”
Highly infectious variants of Covid-19 that showed some resistance to vaccines also pose a challenge, said Fauci. “You are in a fine zone if you don’t have the full impact” of two doses, he said.
Fauci’s comments come at a time when some health experts and public health officials argue that the United States should prioritize giving Americans only one dose of vaccines before moving on to second doses, accelerating the pace of vaccinations across the country.
Unlike the Johnson & Johnson vaccine, which requires a dose, Pfizer and Moderna vaccines require two injections given three to four weeks apart. In the UK, health officials have 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 Vaccine and Related Biological Products Advisory Committee that reviewed Pfizer and Moderna vaccines for emergency use authorization, told CNBC last week that studies have shown that immunity does indeed appear to be more “durable” after the second dose, which means that the protection can 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, scientists also detected 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 on Monday that he “respects” the arguments for a single-dose strategy, but added that the United States currently has enough doses to provide Americans with the first and second doses. “Although we always remain open-minded, we consider the path we have taken the best,” he said.