Third wave of coronavirus infections in the U.S.? More like 'wildfire,' epidemiologist says

Coronavirus cases are climbing at an alarming rate in the U.S., raising fears that parts of the country are in a third wave of Covid-19.

Nationwide, cases Friday were 79,303, the second day in a row of record-setting confirmed new cases of the coronavirus. Over the weekend, the U.S. added 79,059 cases on Saturday and 64,603 cases on Sunday according to an NBC News tally. According to the COVID Tracking Project, the 7-day average for new cases of the coronavirus is 69,692, the highest number to date. There are also nearly 43,000 Americans hospitalized with Covid-19, the highest number since August 19th.

Fewer than 10 states in the country are not experiencing increases of infection.

During an outbreak, a "wave" comes from the curve used to visualize the number of people infected. If more people get sick every day, the curve goes up. If fewer people get sick every day, the curve goes down. Even during the summer, experts say cases in the U.S. never got to a low-enough level of new cases to make it out of the first wave from the spring when cases rose astronomically.

“I look at it more as an elongated exacerbation of the original first wave,” Dr. Anthony Fauci, director of the National Institute for Allergy and Infectious Diseases, said Monday at an annual event for Yahoo Finance. “It’s kind of semantics. You want to call it the third wave or an extended first wave, no matter how you look at it, it's not good news.”

Fauci and other experts are particularly concerned that the recent surge in cases is starting from a higher baseline of roughly 40,000 cases per day, compared with 20,000 cases per day during the summer surge.

“Each wave we start from a higher baseline and we start climbing,” Dr. Ashish Jha, dean of the Brown University School of Public Health said, noting that during the summer, infections were rising most in the South and Southwest. "This time, it's all around the country and we're heading into winter, where the virus becomes more efficient in spreading."

Still, Jha said the terminology isn’t as important as Americans understanding that the growth of new cases can quickly become exponential.

"The metaphor of a wildfire is probably better," said William Hanage, an associate professor of epidemiology at Harvard T.H. Chan School of Public Health. "It's indisputable that the U.S. is now seeing a pretty widespread transmission across the board."

Unlike a wave, which comes and passes through, wildfires can be patchy and more intense in areas, similar to the situation in the U.S., Hanage said. Community mitigation efforts such as masking and social distancing can stamp out the spread, but then infections tend to pop up in other areas with more relaxed measures.

Tara Smith, an infectious diseases epidemiologist at Kent State University in Ohio, is not a fan of the wave terminology. “That implies there's a trough, and our cases have never really declined that significantly,” she said.

Small gatherings are now playing a larger role in driving transmission, Smith said, and can be tied to the fatigue from a pandemic nearing its eighth month.

“Everyone wants to feel a bit of normalcy, even if for an evening,” she said.

As the U.S. heads into the winter holiday months, doubling-down on basic public health measures is even more crucial, especially wearing a mask and avoiding crowds and close contact in closed spaces with poor ventilation, experts say.

“When you're dealing with the first full winter of the worst pandemic that we have seen in a century, the capacity for chaos is there and is real," Hanage said. "The virus likes chaos."