COVID-19 Is in Mysterious Retreat—Is the Worst of the Pandemic Behind Us?

New cases have plummeted in the U.S. and other countries since August. Epidemiologists do not fully understand why.

A woman wearing a mask walks the Brooklyn Bridge in the midst of the coronavirus (COVID-19) outbreak on March 20, 2020 in New York City. Victor J. Blue/Getty Images

Is the worst of COVID-19 behind us? It certainly seems so if you look at the trend line of recent CDC data and vaccination rates (thanks to vaccine mandates). In the past month, average daily cases in the U.S. have fallen by more than a third. Worldwide cases, too, have dropped more than 30 percent since September.

Sign Up For Our Daily Newsletter

By clicking submit, you agree to our <a rel="noreferrer" href="">terms of service</a> and acknowledge we may use your information to send you emails, product samples, and promotions on this website and other properties. You can opt out anytime.

See all of our newsletters

The New York Times‘ daily newsletter, The Morning, noted a mysterious “two-month cycle” of the coronavirus since it began spreading in late 2019. “Cases have often surged for about two months—sometimes because of a variant, like Delta—and then declined for about two months,” observed the newsletter’s author, David Leonhardt.

The pattern has been repeatedly seen in countries with varying vaccination and social distancing rules and hard-hit U.S. states. Yet, epidemiologists do not understand why. Human behavior and the virus’ biology may have both played a role. “Perhaps each virus variant is especially likely to infect some people but not others—and once many of the most vulnerable have been exposed, the virus recedes,” Leonhardt wrote. “And perhaps a variant needs about two months to circulate through an average-sized community.”

All that’s to say that the virus could still make a comeback, especially with the onset of the cold weather, the holiday season and more indoor activities. But this time could actually be different.

Scott Gottlieb, the former commissioner of the FDA from 2017 to 2019 and a board member of Pfizer, recently predicted that the Delta variant might be the last major wave of infection and that, after it has run its course, we will transition from a “pandemic phase” of COVID-19 to a less dire “epidemic phase.”

Reiterating this point in an interview with Barron’s last week, Gottlieb said, “I think Thanksgiving is still a reasonable base case for the U.S. and that Delta is the last major surge of infection. We’re exiting the pandemic phase of this virus in the United States and entering an endemic phase.”

“On the back end of this surge of delta infection, we’re going to have a population where 80 percent to 90 percent of Americans have some form of immunity, either through vaccination or through infection,” he went on to explain. “That’s going to be a pretty robust wall of immunity to prevent this virus from continuing to spread at current levels.”

Adding to this optimism is last week’s announcement of Merck and Bridgeback’s highly effective antiviral pill, molnupiravir, the first oral COVID-19 treatment intended for widespread use outside the hospital, and an impending FDA authorization of the Pfizer-BioNTech vaccine in young children.

Pfizer said Thursday it has asked the FDA to expand the use of its COVID-19 vaccine in children ages 5 to 11. The news came at a desperate time, with the new school year in session and the Delta variant leading to a surge in hospitalizations, including among young kids who are currently not eligible for vaccination.

An FDA advisory team is scheduled to meet on October 26 to discuss Pfizer’s data on its vaccine’s efficacy in children. An official approval for expanded use could follow in November.

Asked about his first impression on molnupiravir, Gottlieb said Merck’s data is “probably the most profound result I’ve seen in an oral antiviral for a respiratory disease in modern times.”

“I think we’ll soon have one or more orally available antiviral drugs alongside effective vaccinations combined with therapeutic antibodies. Overall, this is going to become a manageable threat as a result of our technology.”

COVID-19 Is in Mysterious Retreat—Is the Worst of the Pandemic Behind Us?