Dr. Rochelle Walensky, the director of the Centers for Disease Control and Prevention, said Wednesday morning that she believes the U.S. can stem the current rise in COVID-19 cases in the span of a "couple of weeks" without implementing more mask mandates — but only if Americans heed new guidance and get vaccinated.
Walensky's comments came a day after the CDC changed its guidance on mask usage, saying vaccinated people should resume wearing masks while indoors in areas where the spread of COVID-19 is high.
The new guidance backtracks on a policy set in May that said that people who are fully vaccinated can safely go without masks and social distancing, as studies showed that it was rare for those vaccinated to pass the virus on to others.
Walensky said the new CDC guidance was driven by the spread of the delta variant, a more transmissible strain of COVID-19 which she described as a "different beast."
"With the delta variant, we now see in our outbreak investigations that have been occurring over the last couple of weeks...that if you happen to have one of those breakthrough infections, that you can actually now pass it to somebody else," Walensky said during an appearance on CNN.
When asked Wednesday if she expected case rates to continue to rise into the fall months, Walensky said Americans could flatten the curve before then.
"We can halt the chain of transmission," she told CBS News. "We can do something. If we unify together, if we get people vaccinated who are not yet vaccinated, if we mask in the interim, we can halt this in just a matter of a couple of weeks."
However, Walensky did not rule out the possibility of implementing further restrictions should the rate of spread continue to climb.
"We will follow the science, and we will have the science lead the recommendations that we make," she told CBS News.
Walensky said that while the delta variant has made people who have gotten a shot more vulnerable to the virus, the majority of the spread is coming in areas where vaccination rates are low. She said that 80% of the counties with the highest amount of disease have vaccination rates under 40%.
Nationally, the CDC says that about 57% of the country is fully vaccinated.
"There is no doubt that the reason we have so much disease right now is because it has gone after those who are unprotected, unvaccinated," Walensky said. "The vast majority of transmission that is happening in this country is happening among unvaccinated people."
According to the CDC, the three COVID-19 vaccines approved for emergency use in the U.S. — Pfizer, Moderna and Johnson & Johnson — provide a high degree of protection against the delta variant and near-complete protection against hospitalization and death from COVID-19.