COLUMBUS, Ohio (WCMH) — The seasonal flu peaks in the fall and winter before waning, although transmissions still occur in the summer at a reduced rate.
Experts caution that there is no way of predicting whether the spread of the novel coronavirus will be mitigated by warmer weather. However, there are several academic studies that suggest the majority of historic pandemics were far more severe in temperate regions with cold winters. Southern states in the U.S., and countries in tropical climate, have had fewer coronavirus cases reported.
There has been anecdotal evidence that viruses survive on surfaces longer in colder and drier weather and are also more easily passed on from host to host. The peak transmission period for seasonal viruses, such as influenza and pathogens responsible for the common cold, occurs between November and April in the Northern Hemisphere.
However, not all viruses exhibit the same pattern, or any at all. Tuberculosis and polio outbreaks hit harder in warmer climates. A further challenge is that the novel coronavirus outbreak this year started later (winter) in China and South Korea.
There are four coronaviruses that cause the common cold that decrease in the warmer months. The SARS (2002-2003) epidemic and Swine flu (2009-2010), an H1N1 virus, generally followed a seasonal pattern, peaking in the colder months, and then fading.
The Spanish flu pandemic in 1918, which killed an estimated 50 million people worldwide (675,000 in the U.S.), also declined in summer, followed by a huge fall resurgence that proved deadly. This occurred after the return home of World War I troops from across the Atlantic, after the Allied victory in November 1918.
Dr. Iahn Gonsenhauser, Chief Quality and Patient Safety Officer at Wexner Medical Center, Internal Medicine provider said, “In the winter months, obviously runny noses, a lot more coughing, a lot more congestion, a lot more bodily secretion that are hard to control — that’s the primary spread for viruses.”
He said, “As far as the weather goes, we really don’t see weather as a necessary implication for flu patterns for viral respiratory patterns or for viruses in general.”
Gonsenhauser explained the uncertainties about the pattern of the novel coronavirus.
“This is new. We haven’t seen this specific pathogen before, so it’s hard to really predict. Anecdotally speaking, when we look at other coronaviruses they tend to wane in the warmer summer months, so we would expect the same about this one as well.”
“But, seasonally we do see some changes and historically and anecdotally what I can reference is that we do typically see a drop off in coronavirus, the typical coronavirus that we have seen in the past. So, not the novel coronavirus, but in typical coronavirus, we have seen a pretty significant drop off as we move out of the winter months and into the warmer months,” explained Gonsenhauser.
The highly cautious hope among some experts is that warm, humid weather in the Northern Hemisphere and at least two months of social distancing, combined with some form of antiviral medication, will stem the tide of the coronavirus.
COVID-19 is an upper respiratory illness or infection that can be accompanied by a fever, chills in period that varies from hours to days, and can lead to a life-threatening pneumonia. The symptoms can be mild and confused for allergies or a common cold, or not evident at all, yet a person can be a carrier.
“The best distinguishing feature is if you come into contact with somebody, direct contact with somebody who has been diagnosed, or if you have traveled to a high-risk area. At this rate that’s China, Italy, South Korea, and Iran,” Gonsenhauser said.
The novel coronavirus is too new to discern clear patterns, but it is more easily spread than most coronaviruses and potentially more deadly than the seasonal flu.
“It depends which data set you look at. MERS and SARS were 6 to 8 percent mortality range. Be careful how you’re interpreting it because it’s still outstanding. But, if you look at South Korea which has the most complete data set, they’ve ended up at about 0.5% mortality, which is significantly lower than what we’re seeing elsewhere,” Gonsenhauser said.
Even ss the weather warms, the best advice is to just keep washing your hands and monitoring your symptoms, because at this stage so much is unknown about the novel coronavirus. And experts warm that even if it diminishes in the summer, it is impossible to forecast whether it will return in the autumn with comparable severity.