Dr. Scott Gottlieb says vaccinated people cannot 'throw caution to the wind' due to delta variant

Dr. Scott Gottlieb on Friday urged fellow vaccinated Americans to be on guard about the Covid delta variant, telling CNBC its highly transmissible nature cannot be ignored even by people who have immunity protection.

“The original premise around the vaccines — that they reduce the risk of serious disease and hospitalization — is still intact,” the former Food and Drug Administration commissioner said on “Squawk Box.” “We still see in the data that the vast majority of people who are getting in trouble with Covid are people who are unvaccinated.”

However, Gottlieb, who serves on the board of Covid vaccine maker Pfizer, said the risk to vaccinated people is not zero.

“People who are vaccinated in a setting of this epidemic surge, especially if they’re in places where there’s a high prevalence of infection, need to take appropriate precautions,” he said. “You can’t just throw caution to the wind. You can still become a vehicle for spread in your community.”

The seven-day average of daily new coronavirus cases in the U.S. is 141,060, according to a CNBC analysis of Johns Hopkins University data. That’s up 14% from a week ago. Cases are increasing by more than 5% in 42 states plus Washington, D.C.

Gottlieb’s comments Friday came in response to a question about three vaccinated U.S. senators — Roger Wicker, Angus King, and John Hickenlooper — who announced a day earlier they had tested positive for Covid.

“I think there’s now a recognition that this delta is sufficiently contagious that it can pierce the protections offered by the vaccine, particularly if you were vaccinated a while ago and have declining immunity, as these senators probably did because they were vaccinated a long time ago,” said Gottlieb, who led the FDA from 2017 to 2019.

While some scientists disagree with U.S. health officials’ recent decision to authorize Covid booster shots beginning next month, Gottlieb said he believes the delta variant’s transmissibility supports the idea of delivering third doses to Americans. Noting his role on Pfizer’s board, Gottlieb said he’s studied the data that shows declining immunity protection over time.

“It happens to be the case that we vaccinated some of our most vulnerable older individuals in our society last December and January, particularly nursing homes,” Gottlieb said. “I think the prudent thing to do would be to get additional immunity in that population, especially considering the fact we’re dealing with a much more contagious variant.”

Disclosure: Scott Gottlieb is a CNBC contributor and is a member of the boards of Pfizer, genetic testing start-up Tempus, health-care tech company Aetion Inc. and biotech company Illumina. He also serves as co-chair of Norwegian Cruise Line Holdings’ and Royal Caribbean’s “Healthy Sail Panel.”