Edith Arangoitia, 46 (who came to accompany her elderly mother) is vaccinated with the Pfizer-BioNTech Covid-19 vaccine by Dr. Galen Harnden at La Colaborativa in Chelsea, Massachusetts, on February 16, 2021.
Joseph Precious | AFP | Getty Images
Dr. Anthony Fauci, the White House chief adviser, said Monday that Americans should continue to receive two doses of Pfizer and Moderna Covid-19 vaccines, despite a recent U.S. study that showed photos are extremely effective after a single dose.
A Centers for Disease Control and Prevention study published last week found that a single dose of Pfizer or Moderna Covid-19 vaccine was 80% effective in preventing coronavirus infections among medical staff and other key workers. Two doses are better than one, federal health officials said, adding that vaccine efficacy increased to 90 percent two weeks after the second dose.
While 80% was great news, Fauci said on Monday that he was still worried about the duration of protection after a single dose, especially with the emergence of highly contagious variants that have demonstrated the ability to evade vaccine protection.
“When you look at the level of protection after a single dose, you can tell it’s 80%, but it’s somewhat 80% weak,” Fauci said during a White House news briefing on pandemic. “When you leave it in a single dose, the question is how long does it last?”
Highly infectious Covid-19 variants that have shown some resistance to vaccines are also a challenge, Fauci said. “You are in a fragile area if you do not 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 give priority to administering only one dose of vaccines to Americans before switching to secondary doses, accelerating the pace of vaccinations across the country.
Unlike the Johnson & Johnson vaccine, which requires a single dose, the Pfizer and Moderna vaccines require two vaccines given at a distance of three to four weeks. In the UK, health officials have decided to extend the time between the first and second dose to 12 weeks in an effort to speed up vaccinations.
Fauci has repeatedly said in recent months that the United States should comply with the two-dose regimen.
Dr. Paul Offit, a voting member of the FDA’s Advisory Committee on Vaccines and Related Biological Products, which looked at both the Pfizer vaccine and the Moderna vaccine for emergency use, told CNBC last week that studies showed that immunity actually seems to be more “durable” after the second dose, which means that 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, the scientists also detected so-called T cells after the second dose, another important part of the immune response, which usually provides a more 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 enough doses to provide the first and second doses for Americans. “Although we always keep an open mind, we believe that the route we follow is the best route,” he said.