Despite a recent study that indicated that a single dose of the Pfizer vaccine is 85% effective against the coronavirus, Dr. Anthony Fauci said on Friday that both the Pfizer and Moderna vaccines should still be administered twice to the public.
While it might be tempting to push back the second dose of the two vaccines in an effort to get more people vaccinated sooner, Fauci said the risk is too great.
“There's no doubt about that, that you have an optimal response,” Fauci said on Friday. “When you're dealing with variants, you want enough of a height of a response that even if you diminish it, you don't diminish it so much to get out of the realm of protection, number one. “No. 2, if you do have a less-than-optimum response, you could theoretically and inadvertently be selecting immunologically for variants.”
Fauci also said that a second COVID-19 vaccine dose makes the vaccine more "durable."
"And the reason is, even though you can get a fair degree of, quote, 'protection' after a single dose, it clearly is not durable," Fauci said. "We know that. The durability is not as much as the durability that you would get with the boost.
"If you look at the difference between the degree -- the intensity of the response after a first dose and compare it to that of the second dose, the second dose is 10 times higher in the sense of level of neutralizing antibodies, which is one of the parameters of immunity."
There are currently two coronavirus vaccines that have garnered an emergency use authorization from the FDA. A vaccine produced by Pfizer, which studies indicate has a 95% efficacy rate, began being administered in the US last month. A second coronavirus vaccine, which is produced by Moderna and has a 94% efficacy rate, began being administered last month as well.
The second dose of the vaccine is schedule to come three to four weeks after the first dose, depending on the vaccine.
The FDA also may soon consider one-shot coronavirus vaccines. Earlier this month, Johnson & Johnson submitted its one-shot COVID-19 vaccine for FDA emergency use authorization.