For the first time since early August, COVID-19 cases in the U.S. have dropped below 100,000 a day. Hospitalizations and daily death tolls are going down nationwide as well, even though some states haven’t reached their peak yet. So what is causing the overall decline?

Among the theories is that the highly infectious Delta variant might naturally decline after a two- to three-month period.

So is that possible? And what does it mean for the future of the pandemic?

Dr. Jennifer Nuzzo, an epidemiologist at John Hopkins University’s Center for Health Security, talks to host Scott Tong about the theory.

This article was originally published on WBUR.org.

Copyright 2021 NPR. To see more, visit https://www.npr.org.