Merck CEO Kenneth Frazier said Thursday that drugs to treat or prevent Covid-19 aren't a "silver bullet" solution to the pandemic, predicting people will need to wear masks and practice social distancing measures well into 2021.
"I don't see the therapeutics that we have — or the vaccines that are coming — as a silver bullet," Frazier told CNBC's "Squawk Box," saying that people will still have to practice mask wearing and social distancing "for the foreseeable future."
"I think that's with us for a while, and I would say certainly well into 2021 we'll still be trying to observe these public health measures," he said.
As coronavirus cases continue to surge to record highs, the U.S. is racing to develop and distribute a Covid-19 vaccine under the federal government's Operation Warp Speed program. Some of those candidates from Pfizer and Moderna have fully enrolled people in their clinical trials and could be granted an emergency use authorization from the U.S. Food and Drug Administration by the end of this year.
Frazier said "he's very optimistic that in the near future" there will be positive results coming from late-stage clinical trials for coronavirus vaccines and therapeutics. However, a potential vaccine likely won't be widely available for people until mid-2021.
Dr. Robert Redfield, director of the U.S. Centers for Disease Control and Prevention, has previously told lawmakers that a face mask could provide better protection against Covid-19, even when a vaccine is approved. That's because a potential vaccine, which will likely be available in limited quantities by the end of this year, may only be 70% effective.
The effectiveness, or immunogenicity, measures a vaccine's ability to build an immune response to the virus. Other top health experts, including White House coronavirus advisor Dr. Anthony Fauci, have said the likelihood of producing a highly effective Covid-19 vaccine — one that provides 98% or more guaranteed protection — is slim.
"I think it's a mistake to tell people ... that it's a silver bullet and overnight we're going to be able to vaccinate enough people, treat enough people," Frazier said. "The natural history of these viruses is that they don't go away."
"I don't think we should tell people that they can expect to give up on those public health measures anytime soon," he said.
Merck is developing two separate potential coronavirus vaccines, though it jumped into the race later than its peers. The company acquired Austrian vaccine maker Themis Bioscience, which is developing a Covid-19 vaccine with Institut Pasteur and the University of Pittsburgh and began its phase one trial in August.
Clinical trials for another vaccine, which Merck is developing with scientific research nonprofit IAVI, are expected to begin later this year, the company has previously said.
It's also producing an oral therapeutic in collaboration with Ridgeback Biotherapeutics, known as MK-4482, that would fight against Covid-19 in seriously ill patients. Frazier told CNBC on Thursday that he expects interim data from the drug's trials in early 2021.