About delta variant

As the widely infectious delta variant of Covid-19 spreads across many Western and Southern U.S. states, its high transmission rate could boost current levels of immunity from about 50% to 85%—even if vaccination rates continue to plateau, Dr. Scott Gottlieb, a former chief of the Food and Drug Administration, said during an interview Sunday.

• “Given how transmissible this variant is,” Gottlieb told CBS News’ This Week it’s likely about 85% of the U.S. population will end up with some level of Covid-19 immunity.

• With about 55% of the population at least partly immune due to vaccination and one-third of Americans having been naturally infected, Gottlieb noted that millions of Americans remain vulnerable and now have a “choice in terms of how [they] acquire immunity.”

• Even those immune through natural infection are at heightened risk, Gottlieb said, pointing to data showing immunity among individuals naturally infected with Covid-19—and particularly those who are older—declines after about eight months.

• The physician predicted Covid will effectively act as a “second circulating flu this winter,” though he said its prominence “could be a little worse.”

“I wouldn’t be declaring mission accomplished. I think this is going to be a long fight,” Gottlieb said Sunday. “You’re seeing a decoupling between cases, hospitalizations and deaths because there’s so much immunity in the population—not just through vaccination—but also through prior infection… But this is likely to become an endemic virus. We’re going to have to deal with it.”

Since the start of the pandemic, experts have long said Covid-19’s threat would largely wane once herd immunity is reached, referring  to a large-enough proportion of immunity that effectively makes person-to-person transmission highly unlikely within a community. Dr. Anthony Fauci, the nation’s top infectious disease expert and head of the National Institute of Allergy and Infectious Diseases, has said that could happen at about 70% to 85% immunity, but others in the medical community have warned the highly transmissible delta variant could push the required immunity threshold higher. “The most important thing we can do to stop the spread of Covid-19 and the variants is ensure everyone who is eligible gets vaccinated,” California public health officer Dr. Tomás Aragón said in a statement last week while cautioning residents that infection rates were once again rising as the delta variant became the state’s dominant strain.

70%. That was the percentage of Americans President Joe Biden was hoping would get vaccinated by July 4. Although 67% of American adults have received at least one dose, an overwhelming majority of states failed to meet Biden’s goal.

• Edited and written by Emirhan Tongün.