Studies show warm weather can slow coronavirus, but won’t stop it

Warm temperatures slow down the spread of the novel coronavirus — but don’t completely eradicate it, according to new studies.

Scientists at the Massachusetts Institute of Technology found that 90 percent of COVID-19 transmissions that occurred until Sunday happened in regions with low temperatures — between 37.4 and 62.6 degrees Fahrenheit.

Coronavirus cases have been reported in countries with equatorial climates and those in the Southern Hemisphere —which are now in summer.

But regions with average temperatures above 64.4 degrees Fahrenheit currently account for fewer than 6 percent of global cases so far.

“Wherever the temperatures were colder, the number of the cases started increasing quickly,” Qasim Bukhari, a computational scientist at the university who co-authored the study, told The New York Times. “You see this in Europe, even though the health care there is among the world’s best.”

That pattern applies in the US too, Bukhari told the paper.

The outbreak has developed more slowly in southern states like Arizona, Florida and Texas compared to New York, Washington state and Colorado, for example, according to Bukhari.

In California, the rate is somewhere in the middle.

Epidemiologists have seen a similar pattern with other viruses — including the flu, which generally follows a November to April trend in the Northern Hemisphere, Dr. Deborah Birx, a member of the White House’s coronavirus task force, said during a recent briefing, according to the Times.

The four types of coronavirus that cause the common cold also pick up in the winter and drop off in the summer.
At least two other studies have come to similar conclusions — including one conducted by Chinese researchers at Beihang University and Tsinghua University.

The authors found that between January 21 and 23 — before China’s authorities intervened to stop the spread of the deadly bug — the infection was more contagious in northern China, with low temperatures and relative humidity, than in warmer, more humid cities along the southeast coast, according to The Wall Street Journal.

Researchers in Spain and Finland found that the virus tends to spread in regions with dry conditions and temperatures between 28.3 and 49 degrees Fahrenheit, according to the Times.

But these studies have yet to be peer-reviewed and factors such as travel restrictions, social distancing, testing availability and hospital burdens may have influenced the results.

Policymakers should not become complacent in hopes that the virus will die out as temps warm up, Bukhari told the Times.

“We still need to take strong precautions,” Dr. Bukhari said. “Warmer temperatures may make this virus less effective, but less effective transmission does not mean that there is no transmission.”

Public health officials at the World Health Organization and the U.S. Centers for Disease Control and Prevention say it’s too soon to draw any conclusions about the infection’s seasonal behavior, according to the Journal.

Expert Andy Pekosz, a microbiologist at the Johns Hopkins University Bloomberg School of Public Health who wasn’t involved in the studies, told the paper it’s safest to assume the virus won’t taper off in the summer.

“We don’t know with the COVID-19 virus how it will behave in the warmer weather,” Pekosz said. “Prepare for having to deal with this in the summer months and assume there will be no respite.”