Gottlieb: Delta Variant Lessened Vaccine's Ability to Prevent Spread

Former Food and Drug Administration administration Dr. Scott Gottlieb insisted Sunday that vaccines provide strong protection against serious illness or death from COVID-19, but the delta variant has lessened the ability of the vaccines to prevent the disease from spreading through vaccinated people. 

"What we see with the delta variant (the premise) is diminished," Gottlieb said on CBS's "Face the Nation." "There is more evidence that people are likely to spread the delta variant even after vaccination than they were likely to spread the other variants, but it's still a very small percentage of people."

He pointed out that the original premise behind the vaccines was not that they would block COVID infections altogether, but that they would reduce the risk of death and hospitalizations, and that is still "fully intact."

The second premise was that the vaccines would reduce the risk of infection and transmission and would be important in ending the epidemic, said Gottlieb, but with the delta variant, that risk has grown.  

"We need to recognize, especially for vaccinated people who might be in contact with young children, with elderly individuals who are at risk, that there is a risk that they could develop a mild or asymptomatic infection and go on to spread it to others.

Meanwhile, a study from Provincetown, Mass., found the amount of virus present in vaccinated people was the same as those who have not been vaccinated, and the CDC has inferred that that means there is more risk of transmission from vaccinated people, said Gottlieb. 

However, he argued that while nose swabs suggest that there is the ability to spread the virus, that doesn't prove vaccinated people are equally able to pass it along, said Gottlieb. 

"You really want to measure virus levels in the lower airways because that's where aerosols are created, and we know that you spread this virus through aerosols," said Gottlieb. 

Further evidence also shows that vaccinated people with higher levels of the virus can see those levels drop after a day or two, meaning they're much less likely to spread the virus.

"Initially, someone who's vaccinated may- may have the same level to spread the virus, may be on par with someone who's unvaccinated, but their ability to spread the virus probably diminishes more quickly," he explained. "Out in the community, if you were measuring their ability to transmit the virus, you would probably see, on the whole, they're less likely to be contagious."

Meanwhile, the findings on breakthrough cases point to the need for booster shots, particularly among the elderly and vulnerable population, said Gottlieb. 

"If you see some decline in their ability to protect particularly older individuals, vulnerable individuals from any infection at all, that's suggestive that eventually, you're going to see the- the infection break through in more cases in those individuals and start causing symptomatic illness," he concluded. 

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