Temperatures are expected to take a dip in Calgary this weekend, and with many questions swirling about how warmer weather could slow the spread of COVID-19, some are wondering what impact a cold snap might have.
“The simple answer is, we really don’t know,” Dr. Craig Jenne, associate professor of microbiology, immunology and infectious diseases at the University of Calgary, told Global News on Friday.
While Jenne said there’s no evidence to suggest that changes in temperature, particularly warmer weather, could slow the spread of COVID-19 — which tends to be the case with other viruses — experts do agree that colder weather can make people more susceptible to contracting it.
Why?
Because cold air typically means dry air.
“The air, quite importantly, is dry in the winter and that allows the virus easier access into our airways,” Jenne said. “Moist air helps keep our airways moist and the virus doesn’t get in.
“Breathing dry air in, your lungs are actually going to humidify that air, so you are losing a little bit of the moisture which dries out the surface of our airways — nose, throat and our lungs — and when those surfaces are dry, we are missing that little bit of mucus and that mucus is actually a protective layer.
“When our airways dry out, it allows the virus to directly get at our cells and enter our body.”
Viruses like influenza, for example, tend to see spikes in cases on a seasonal basis, with the traditional “flu season” happening in winter and then dying down in the spring. Jenne said that’s not necessarily going to be the case for the novel coronavirus, as it’s too early to tell whether COVID-19 is seasonal, too.
“Unfortunately, we still don’t know much about the coronavirus, and to group this virus in with all viruses is similar to saying that a snake is the same as an elephant,” Jenne said.
“They are quite different entities: they happen to be viruses, they happen to affect our airways, but they are structurally very different, genetically very different, their mechanism of entering our body are very different. So it’s really hard to extrapolate what we know about some viruses back onto the novel coronavirus.”
He said what experts do know is that in cold weather, people tend to turn up the heat which further dries out their homes and then, in turn, their respiratory systems. And considering people are self-isolating and staying in their homes for more time than is normal for most, it could make it easier to pick up the virus.
“It doesn’t really matter how long that virus survives, we already know it can live on a surface for a day or two, so if it survives even longer it doesn’t really matter, if you are touching that surface the same day you are going to pick up the virus,” Jenne said.
“What’s more important is ensuring our airways are protected, we are washing our hands and we are maintaining these social distancing bubbles.”
Jenne also said it’s important to note that COVID-19 is spreading in areas with climates much warmer than what Calgary, and much of Alberta, is experiencing so far this spring.
“I don’t know if the temperature is really going to matter,” he said.
“What is going to matter though is individual health, individual immunity. So it is get good sleep, don’t let your body get run down, stay hydrated, eat well if you can, keep stress in check, washing your hands regularly, all of those things are probably going to have a much bigger impact on the virus than the actual temperature.”