Claims that high heat and humidity levels are able to kill the coronavirus and slow the spread of Covid-19 have been passed around since the emergence of the disease.
The Myth:
The high levels of heat and humidity in environments like Cambodia kills the Covid-19 coronavirus quicker and lowers the infection rate.
Fact or Fiction?
Unknown
What You Need to Know:
There have been many news sources and internet rumors claiming that high heat and humidity levels are an effective tool in combating the spread of Covid-19. Even some world leaders, such as United States President Donald Trump,have parroted the same information as an established fact.
The truth, however, is that there is yet to be any conclusive evidence either confirming or debunking those assertions.
There has been one published study out of Beijing that links high heat and humidity levels to lower infection rates, but the study has not been peer-reviewed. The study looks at the effect that temperature and humidity have on the R0 (R-naught) value, which refers to the rate that one infected person will infect others. For example, an R0 of 1 would denote that on average every infected person would infect one other person, with values below 1 meaning the disease is in decline.
According to a report published by the World Health Organization (WHO), the R0 for Covid-19 seems to be around 2 to 2.5, depending on a number of factors. In comparison, the R0 for the flu is 1.3.
The Beijing study claims that a rise of one degree Celsius of temperature and one percentage of relative humidity lowers the R0 of Covid-19 by 0.0225 and 0.0158, respectively. This means, taking the lower end estimate of an R0 value of 2, there would need to be a 31-degree Celsius increase or a 44 percent increase in relative humidity, or some combination of the two, to bring the Covid-19 infection rates inline with the flu.
However, even if infection rates do slow down to flu levels, the coronavirus is exponentially more deadly. Initial crude mortality numbers put the mortality rate of Covid-19 at 3-4%, whereas the flu is well below 0.1%. This means that Covid-19 is at least 30 times more deadly than a disease that kills at least 290,000 and up to 650,000 people worldwide every year.
Another factor to take into consideration is that the world does not experience the same seasons at the same time. While temperatures will begin to rise in the northern hemisphere as it enters summer time, the southern hemisphere will be heading into the colder months of fall and winter.
That being said, we are unable to say with any certainty that these assumptions are correct. The Beijing publication has not been peer-reviewed to ascertain its validity and no subsequent replication of the study has been performed to confirm the results.
Scientists within China have even refuted the effects of heat on the virus outside of a laboratory setting.
“The virus is heat sensitive, but that’s when it’s exposed to 56 degrees Celsius for 30 minutes and the weather is never going to get that hot,” said Wang Guiqiang, head of the infectious diseases department of Peking University First Hospital, in late April. “So globally, even during the summer, the chance of cases going down significantly is small.”