Will Summer Sunshine Suppress Coronavirus Pandemic?
By Riaz Haq
CA
Preliminary results of a US Government study reveal that sunlight quickly destroys COVID19, the novel coronavirus. The study found that the risk of “transmission from surfaces outdoors is lower during daylight” and under higher temperature and humidity conditions, according to Yahoo News. This latest work reinforces "Will Coronavirus Pandemic Diminish by Summer?", a recent paper written jointly by Pakistani and Indian researchers at the Massachusetts Institute of Technology.
Homeland Security Study
A study by US Department of Homeland Security scientists concludes that “sunlight destroys the virus quickly” but warns that enclosed areas with low humidity, such as airplane cabins, “may require additional care to minimize risk of transmission. “Simulated sunlight “rapidly killed the virus in aerosols,” the study says, while without that treatment “no significant loss of virus was detected in 60 minutes. “While the DHS describes the results as preliminary, they may eventually make their way into specific recommendations. “Outdoor daytime environments are lower risk for transmission,” the briefing states.
Dr Qasim Bukhari's Work
Dr. Qasim Bukhari, a Pakistani-American scientist at MIT, told Yahoo News that since he and his colleagues published that analysis the numbers of the coronavirus spread continue to support their contention. “They are doing a lot of tests now in India. Also, when you look at the numbers in Pakistan it’s the same. There are more than 5,000 cases in Pakistan right now,” he said. “But the increase is not as rapid as you see in other countries.”
Last month I followed up with Dr Bukhari, who happened to be a fellow NED University alumnus from Karachi, about his findings. Here's a brief Question/Answer version of the email exchange I had with Dr Bukhari:
RH: My understanding from the data I have seen from various sources is that the coronavirus transmission rates decline but do not necessarily go to zero in hot and humid weather. And the reason is that the fatty outer layer of the virus has trouble in heat and humidity. Is that accurate?
QB: That would be almost accurate. The only thing we don't know so far is, how much decline in growth rate we are talking about. It is definitely non-zero. The underlying reasons may be many or either of many. One reason could be the fatty outer layer reason that you mentioned. Other reason could be the antibacterial nature of sunlight, another reason could be low indirect transmission (through air) in high humidity.
"There is indeed evidence that weather plays a role, but in no way we are suggesting that this role alone would be so decisive as to completely halt the spread of COVID. And anyway, the effect of this weather would only be relevant in humid hot countries. Please do share, but please use the right words that properly communicate that it is incredibly important to take precautions and quarantine measures even in the most humid hot regions, as the spread would keep on going without that, we have evidence from Singapore, Malaysia and Indonesia of this."
Wang, Weifeng, Beihang and Ke Tang
There is similar work that has recently been published by a Chinese research team that included Jingyuan Wang, Kai Feng, Weifeng Lv of Beihang University, and Ke Tang from Tsinghua University. They studied 100 different Chinese cities that each reported more than 40 cases of COVID-19 from Jan. 21 to 23, 2020.
“In the early dates of the outbreaks, countries with relatively lower air temperature and lower humidity (e.g. Korea, Japan and Iran) saw severe outbreaks than warmer and more humid countries (e.g. Singapore, Malaysia and Thailand) do," the researchers wrote.
Here's an excerpt from the abstract published by the team:
"After estimating the serial interval of COVID-19 from 105 pairs of the virus carrier and the infected, we calculate the daily effective reproductive number, R, for each of all 100 Chinese cities with more than 40 cases. Using the daily R values from January 21 to 23, 2020 as proxies of non-intervened transmission intensity, we find, under a linear regression framework for 100 Chinese cities, high temperature and high relative humidity significantly reduce the transmission of COVID-19, respectively, even after controlling for population density and GDP per capita of cities. One degree Celsius increase in temperature and one percent increase in relative humidity lower R by 0.0383 and 0.0224, respectively. This result is consistent with the fact that the high temperature and high humidity significantly reduce the transmission of influenza. It indicates that the arrival of summer and rainy season in the northern hemisphere can effectively reduce the transmission of the COVID-19."
Some experts are pointing to the increased amount of UV rays from the sun the Northern Hemisphere will be subject to this time of year as a factor that could slow the virus, according to a story in AccuWeather.
Dr Anthony Fauci on Effect of Weather
Dr Anthony S. Fauci, the director of the National Institute of Allergy and Infectious Diseases (NIAID) who also serves on the White House coronavirus task force, has acknowledged that a change of season might affect COVID transmission rates.
At a White House briefing, he said: “I think it (weather) very well might. And the reason I say that is that what we’re starting to see now in the Southern Hemisphere, in southern Africa and in the southern hemisphere countries, is that we’re having cases that are appearing as they go into their winter season. And if, in fact, they have a substantial outbreak, it will be inevitable that we need to be prepared, that we’ll get a cycle around the second time.”
Summary: A US Government study has found that sunlight quickly destroys the coronavirus. Mainstream US and Indian media have also widely covered a recent MIT paper on the effects of heat and humidity on coronavirus transmission. Dr Qasim Bukhari, the lead author and an alumnus of NED University located in Karachi, Pakistan, has shared data showing that 90% of the coronavirus cases so far have occurred in regions with absolute humidity between 4 and 10 grams per cubic meter. Recent Chinese research also suggests that hot and humid weather may significantly slow down transmission of the coronavirus or COVID-19. An increase of just one degree Celsius and 1% relative humidity increase substantially lower the (Covid-19 or 2019-nCoV) virus’s transmission, says a study published on March 10, 2020 by Chinese researchers. One possible reason is that the fatty outer layer of the virus has trouble surviving in high heat and humidity. The virus disintegrates when the fatty outer cover goes in a way similar to how soap and hot water destroy it. This may explain why there appear to be relatively few reports of local COVID-19 transmissions in places like Pakistan. Most of the known coronavirus cases in Pakistan appear to be those of people who have come into the country from cold, dry places like northern Iran where the pandemic is raging. The rate of local transmission in Pakistan is not zero but relatively low. Dr Bukhari says that "there is indeed evidence that weather plays a role, but in no way we are suggesting that this role alone would be so decisive as to completely halt the spread of COVID."
(Riaz Haq is a Silicon Valley-based Pakistani-American analyst and writer. He blogs at www.riazhaq.com)
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