If Covid-19 acts like other coronaviruses, “it likely isn’t going to be a long duration of immunity,” Fauci, director of the National Institute of Allergy and Infectious Diseases, said during an interview Tuesday evening with JAMA Editor Howard Bauchner.
“When you look at the history of coronaviruses, the common coronaviruses that cause the common cold, the reports in the literature are that the durability of immunity that’s protective ranges from three to six months to almost always less than a year,” he said. “That’s not a lot of durability and protection.”
The National Institutes of Health has been fast-tracking work with biotech firm Moderna on a potential vaccine to prevent Covid-19, which has infected more than 6.28 million people worldwide and killed at least 375,987, according to data compiled by Johns Hopkins University.
Fauci said Tuesday that the biotech company expects to enroll about 30,000 individuals when it begins a phase 3 trial in July. He said there are at least four trials for potential vaccines that he is either directly or indirectly involved in.
Fauci said that by the beginning of 2021 “we hope to have” hundreds of millions of doses.
When asked whether scientists will be able to find an effective vaccine, Fauci said he’s “cautiously optimistic,” adding that “there’s never a guarantee.” He cautioned “it could take months and months and months to get an answer” before scientists discover whether the vaccine works.
U.S. officials and scientists are hopeful a vaccine to prevent Covid-19 will be ready in the first half of 2021 — 12 to 18 months since Chinese scientists first identified the coronavirus and mapped its genetic sequence.
It’s a record-breaking time frame for a process that normally takes about a decade for an effective and safe vaccine. The fastest-ever vaccine development, mumps, took more than four years and was licensed in 1967.
However, scientists still don’t fully understand key aspects of the virus, including how immune systems respond once a person is exposed. The answers, they say, may have large implications for vaccine development, including how quickly it can be deployed to the public.
Fauci, the nation’s leading infectious disease expert, said in congressional testimony last month that he is hopeful scientists would find a workable candidate but warned of potential pitfalls in developing any vaccine.
“You can have everything you think that’s in place and you don’t induce the kind of immune response that turns out to be protective and durably protective,” Fauci said of a vaccine. “So one of the big unknowns is, will it be effective? Given the way the body responds to viruses of this type, I’m cautiously optimistic that we will with one of the candidates get an efficacy signal.”