Many, including President Donald Trump, have posited that warmer weather will eventually get the best of the new coronavirus. However, some infectious disease experts, including a top epidemiologist at Harvard University and the director of the Center for Infectious Disease Research and Policy in Minneapolis, are cautioning that unlike cases of seasonal flu, which tend to decline in the spring and summer months, COVID-19, and SARS-CoV-2, the virus that causes it, will not behave in the same manner.
Lipsitch examined four factors regarding seasonality and transmission of the virus, officially known as SARS-CoV-2, in temperate regions.
“To my knowledge [there] are no specific studies of the role of humidity for coronaviruses or other respiratory viruses besides flu,” Lipsitch wrote.
In the paper, the researchers suggested transmission is possible in many different climates and they cited Singapore as an apt example. Singapore sits near the equator and as of March 11 had reported more than 170 confirmed cases.
The authors of the paper concluded that “weather alone (i.e., increase of temperature and humidity as spring and summer months arrive in the North Hemisphere) will not necessarily lead to declines in case counts without the implementation of extensive public health interventions.”
Human behavior is another factor researchers have addressed. During the winter, people spend more time indoors with less ventilation and personal space than when they venture outdoors in the spring and summer. Lipsitch points out that schools “are a site of much infectious disease transmission.” The 2009 flu pandemic declined in the summer but ramped back up in September, he noted.
Middle East Respiratory Syndrome (MERS), another type of coronavirus, is spread from animals to people in temperatures as high as 110 degrees Fahrenheit in the Arabian Peninsula, Osterholm pointed out as a reason to not bank on warmer weather suppressing the virus.
“There’s no evidence it’s seasonal there,” he said.