COVID-19's influence on global temperature

Coronavirus is afraid of high temperature, but COVID-19 and SARS belong to the same coronavirus, and their gene sequences are 85% similar. Therefore, this actually reflects people's vague expectation that the COVID-19 epidemic will gradually disappear after the arrival of summer, just like SRAS 17 years ago.

According to the knowledge and experience of other coronaviruses, warming weather is beneficial to the decline of incidence.

Indeed, this expectation has some basis. According to the study of SARS, human coronavirus is sensitive to heat, and with the increase of temperature, the resistance of human coronavirus will decrease. 56 degrees Celsius for 30 minutes can effectively inactivate the virus. However, in the maintenance solution at 4℃, human coronavirus can maintain moderate stability, and the storage time can reach several years at MINUS 60℃. Moreover, many studies have shown that the virus activity of MERS coronavirus and SARS virus will be significantly reduced in high temperature and humidity environment. However, under the temperature of 22℃ to 25℃ and relative humidity of 40% to 50% (that is, a typical air-conditioned environment), SARS virus can remain active on a smooth surface for 5 days.

Therefore, the author would like to remind everyone that it is impossible to inactivate the virus by heating the environment with air conditioner at ordinary times, and the temperature of taking a hot bath can not be reached.

In the book How the International Plague of SARS was Stopped, published by WHO in 2006, the warming weather was considered as one of the reasons for the disappearance of SARS. Based on the knowledge and experience of other coronaviruses, Academician Li Lanjuan, Academician Wang Chen, Academician Zhong Nanshan and Director Zhang Wenhong all affirmed that the warming weather is beneficial to reduce the incidence.

Direct research in novel coronavirus supports that high temperature may inhibit the spread of COVID-19.

On February 22nd, Elvis Presley team of School of Public Health, Sun Yat-sen University published a paper entitled "Temperature significantly changes coronavirus pneumonia-the spread of19 in 429 cities" on the preprint platform. In the paper, the Elvis Presley team speculated that there might be the most suitable temperature range for COVID-19 to spread. The recent average temperature in Wuhan is between 4.28℃ and 6. 18℃, which is just within the temperature range where the number of confirmed cases is rising. Therefore, the suitable temperature in Wuhan and the spread of COVID-19 may be one of the factors leading to the first outbreak of the epidemic in the local area. The author also speculated that with the increase of temperature in the northern hemisphere, the epidemic situation may be controlled accordingly after the daily average temperature exceeds the optimal temperature range for virus transmission.

On March 9th, the pre-printed website SSRN published a paper by the Institute of Human Virology of the University of Maryland School of Medicine and the Center of Excellence for Global Viral Networks (GVN), pointing out that the current epidemic situation seems to have a strong correlation with latitude and temperature. The community communication in COVID-19 mainly develops along the east-west direction, with the central points generally distributed along the 30 ~ 50 degrees north latitude, with an average temperature of 5℃~ 1 1℃ and an average humidity of 47%~79%. In the future, the northern hemisphere will heat up and the risk of epidemic areas will further increase northward. In fact, the subsequent development of the epidemic is very consistent with the prediction of this article.

The white circle represents the area where major community communication has occurred. The red isoline marks the temperature range from 5 to 1 1 Celsius.

Contrary or cautious view: temperature is not the decisive factor.

As early as February, in an interview, Michael Osterhome, director of the Center for Infectious Diseases and Policy at the University of Minnesota, expressed doubts about the idea that high temperature inhibits viruses. He believes that it is too early to expect warmer weather to curb the spread of novel coronavirus. "Many people make this judgment because the SARS epidemic ended in summer." He said: "I don't know if it is a coincidence. It may also happen that summer, and humans controlled the epidemic. " He went on to point out that MERS (Middle East Respiratory Syndrome), another coronavirus found in human body in 20 12 years, did not follow the seasonal law at all. "The temperature in the Arabian Peninsula is as high as about 43 degrees Celsius, and MERS is still contagious." In this regard, he pointed out that "the peak of some viruses appears in midsummer."

Maria Van Kokhov, technical director of emergency health events project, was also cautious about the impact of temperature at the World Health Organization General Assembly held on March 5th. "We have no reason to believe that viruses behave differently at different temperatures." He called on every country and region to take active actions to prevent the further spread of COVID-19 virus. On March 6th, Ryan, Executive Director of WHO Emergency Project, also said at a news conference that there was no evidence that COVID-19 would disappear by itself in the summer. Nancy Mesoni, director of the National Center for Immunology and Respiratory Diseases of the US Centers for Disease Control and Prevention, also said in a public conference call that it is not yet certain that the number of confirmed cases will decrease with the warming of the weather, and various positive measures need to be taken. "We don't expect to eliminate this virus just because the weather is getting warmer."

On March 19, two scholars from Massachusetts Institute of Technology published an article entitled "Will the prevalence of coronavirus decrease in summer? On the SSRN preprint platform. Research paper. The results show that the total number of cases in countries with average temperature higher than 18℃ and absolute humidity higher than 9g/m3 in June and March is actually less than 6% of the total number of cases in the world. This study shows the possibility that a warm climate can inhibit the spread of the virus, but on the other hand, it also shows that local transmission cases in southern hemisphere countries may mean that COVID-19 can tolerate higher temperatures than influenza and other respiratory viruses in the past.

A study published by Mark Lipsey, an epidemiologist at Harvard School of Public Health, found that COVID-19 may continue to spread within a certain humidity range, leading to a rapid increase in infection cases, whether in cold and dry areas or tropical areas like Singapore. The study said: "If a wide range of public health interventions are not implemented, weather alone (such as the increase of temperature and humidity in spring and summer in the northern hemisphere) may not bring about a decrease in the number of cases.

At present, there are more and more confirmed cases in tropical countries such as Singapore, Malaysia and Brazil, which seems to illustrate the complexity of the problem.

On March 30th, Academician Shen of Nanjing Medical University and Academician Wang Qilong of Huai 'an First Hospital affiliated to Nanjing Medical University published papers in JAMA Network Open, a top international medical journal. This paper reports a case of cluster transmission in which a super-communicator infected eight other people in a bath center in Huai 'an, Jiangsu Province. This case shows that COVID-19 can still survive under the conditions of high temperature and high humidity, and its spreading power shows no signs of weakening.

The author believes that this article may prove that simple temperature and humidity are not the decisive factors of virus transmission, but temperature is obviously not simple temperature, but also involves environmental factors such as ventilation and sunshine. The increase of temperature is accompanied by the increase of sunshine. Although absolute temperature can't kill the virus, enhanced ultraviolet rays should have a superposition effect. Going out to bask in the sun is definitely beneficial and harmless!

After talking for a long time, some people may say, let you say flowers and plants, but you still have no conclusion. Yes, most people may not find Newton's theorem like Newton when eating apples that fall from trees. Professor Lauren Gardner, the founder of the World Epidemic Map of Johns Hopkins University, also said that she didn't expect her work to attract more than 654.38 billion hits. She said that this project has brought more exposure to the school and the team. "I really hope it can bring really exciting opportunities to our team, and it has already done it." The national aeronautics and space administration of the United States funded this group to study the effects of "seasonality and climate" on the virus. "Ha ha, this is not what I want to be with the US government.