Coming to Grips With the Fall Surge

As predicted, the uptick in cases has begun

Image: Andriy Onufriyenko/Getty Images

Just as scientists predicted, the fall surge of Covid-19 has begun. Since the early days of the pandemic, researchers have warned that the return to school, cooler weather, and the end of outdoor activities could create the perfect conditions for an uptick in new cases. That’s exactly what the numbers are showing now.

In the U.S., the case count has risen steadily in the past two weeks, from 24,257 on September 7 to 39,330 on September 22, according to data collected by Johns Hopkins University (JHU). A graph of the seven-day moving average in the U.S., also from JHU, shows this trend:

After a huge summer spike, Covid-19 cases in the U.S. are again on the upswing. Credit: Johns Hopkins Coronavirus Resource Center

Other countries in the northern hemisphere, where the weather is cooling, are seeing the same pattern. Spain, France, Russia, and the United Kingdom, which are on JHU’s list of the top 10 most affected countries, have all seen a rise in cases in the past seven days.

Even though scientists had warned that this would happen, it’s understandable if this news feels alarming. But take comfort in knowing that scientists understood enough about the spread of the coronavirus that they could predict how it would behave in the fall. Understanding its spread means knowing how to prevent it. And unlike the start of the pandemic in March, we know much more about that now, too.

“Concerns for the winter are primarily related to the transmission dynamics of Covid-19,” Abraar Karan, MD, MPH, an internal medicine doctor at the Brigham and Women’s Hospital and Harvard Medical School, tells the Coronavirus Blog via email. “We know that the disease transmits best indoors, in crowds, and in poorly ventilated spaces.” As I wrote previously, both the droplets and aerosols (tinier particles that can travel farther than six feet) expelled through talking, coughing, and sneezing can spread the coronavirus indoors.

As the weather gets colder, people will naturally spend more time indoors, increasing their risk of spreading the virus. “While the summer gave us the benefit of moving our social activities outdoors, the winter will demand that we…