A Columbia University epidemiologist and his colleagues estimate that 3.6 million Americans are infected with the coronavirus, which they are shedding to others. Dr. Jeffrey Shaman, a professor of environmental health sciences at the university, created a COVID-19 projection model that shows a 34% week-to-week increase but does not include a potentially equal number of latent infections that are still incubating.

“It’s bad; it’s really, really bad,” Shaman said, according to The Washington Post. “We’re running into Thanksgiving now and that’s going to make it worse.”

Researchers at the University of Washington also estimated Tuesday that 3.2 million people have been infected since Election Day, Nov. 3, according to their Institute for Health Metrics and Evaluation, or IHME. These figures, according to the Post, are much higher than official case counts.

In July, Dr. Robert Redfield stated that the actual number of Americans infected by the virus was probably 10 times higher than confirmed cases, based on antibody tests.

“The U.S. didn’t experience a true end of the first wave of the pandemic,” IHME Director Dr. Christopher Murray said in July, according to U.S. News & World Report. “This will not spare us from a second surge in the fall, which will hit particularly hard in states currently seeing high levels of infection.”

Murray’s prediction is proving to be accurate, but according to the Post, the fall wave is “still swelling and is probably many weeks from cresting.” Experts say that the combination of colder weather and indoor gatherings, coupled with human behavior that tends to ignore public health guidelines, has contributed to the rising surge of infections.