More than 1.05 million new cases of pneumonia have been confirmed worldwide, according to the latest figures. Over time, the northern hemisphere is about to enter the summer, while the southern hemisphere is also ushering in winter. Will the increase in temperature weaken the ability of the new coronavirus to spread? Will new coronal pneumonia suddenly disappear in the summer, like SARS or seasonal flu?
Several experts told the China Science Daily that the impact of climate on the spread of the new coronavirus cannot be ruled out, but the hope of controlling the outbreak through rising temperatures is not great.
Temperature and humidity affect virus survival
Previous studies of the effects of climate on the spread of respiratory infections in populations have shown that cold and dry environments contribute to the survival and spread of viral diseases, while warm and humid environments reduce the spread of the virus.
Wang Mao’s team at Sun Yat-sen University’s School of Public Health collected daily confirmed numbers and temperaturedata from 429 cities and regions in China and 26 countries between January 20 and February 4.
They found a link between temperature and the spread of the virus. In low temperature environment, the average temperature increased by 0.83 per day for every 1 degree C increase. When the average temperature rose to 8.72 degrees Celsius, the cumulative number of confirmed people reached a peak.
Subsequently, the number of confirmed daily cases decreased as the temperature rose further.
On March 9, SSRN, the paper’s preprint site, published a paper by the Human Virus Institute at the University of Maryland School of Medicine and the Global Virus Network (GVN) Center of Excellence, finding a correlation between the outbreak of new coronary pneumonia and latitude and temperature.
The article points out that the community spread of new coronary pneumonia is mainly carried out along the east-west, the center point is roughly along the north latitude 30 to 50 degrees distribution, the average temperature is 5 degrees C to 11 degrees C, the average humidity in 47% to 79%.
Outbreaks in these areas coincide with the lowest point of the annual temperature cycle and the lowest temperature below 0C.
Although several studies have shown that high temperatures may inhibit the spread of the new coronavirus, Shen Hongbing, a member of the Chinese Academy of Engineering, Wang Qilong of Huai’an First Hospital, affiliated with Nanjing Medical University, and others, came to different conclusions in a study published March 30 in the Journal of the American Medical Association Network Open.
The paper studied the case of a patient with new coronapneumonia with a history of Wuhan exposure in Huai’an City, Jiangsu Province, who infected 8 people in a bathing center.
The results show that the new coronavirus can survive under high temperature and humidity, and the spread has not decreased.
Prior to that, on March 19th two MIT scholars published a book entitled “Will the summer coronavirus epidemic decrease?” on the preprint platform SSRN. Research papers.
For the study, they focused on the effects of weather on the spread of the new coronavirus.
The results showed that the total number of cases in countries with average temperatures above 18 degrees C and absolute humidity above 9g/m3 between January and March was actually less than 6% of the global total.
The study shows the possibility of warm climates inhibiting the spread of the virus, but on the other hand, there are cases of indigenous transmission in southern hemisphere countries that could mean that the new coronavirus is more resistant to higher temperatures than past flu and other respiratory viruses.
“From the existing scientific literature and news reports can see that the survival of the new coronavirus suitable temperature and range is relatively broad, the environmental adaptability is relatively strong, relatively high and low temperature, may be contagious.
Whether new coronary pneumonia appears in extreme low temperature environment is urgently needed to be studied. Qi Xin, an associate professor in the Department of Epidemiology and Health Statistics at The School of Public Health at Xi’an Jiaotong University, said.
Temperature is not the decisive factor.
The outbreak of new coronary pneumonia is raging around the world, but there are limits to understanding the new virus.
In addition to the study of confirmed cases and climate data, there is also some research on the relationship between the new coronavirus and the pre-temperature virus, which is based on knowledge and experience with other coronaviruses.
China’s CDC previously prepared the “new coronavirus infection of pneumonia public protection guide” pointed out that the human coronavirus is more sensitive to heat, the virus in 4 degrees C suitable to maintain the droplets for moderate stability, but as the temperature increases, the virus’s resistance declines.
Previously, the World Health Organization believed that there were three factors in controlling and eliminating SARS: transparent and open case notifications, effective isolation measures for patients in various countries, and warmer weather.
Shu Yuelong, dean of The School of Public Health (Shenzhen) of Zhongshan University, said in an interview organized by the Chinese Association of Science and Technology that when the SARS outbreak occurred, the world, especially China, had also taken strong preventive and control measures, including rapid detection of cases for isolation, follow-up of each case of the close-knit population for isolation and medical observation and other preventive and control measures, and ultimately successfully prevented and controlled the outbreak.
He stressed that rising summer temperatures may reduce the intensity of the epidemic, but it is unlikely to disappear naturally.
At the recent “Global Anti-Epidemic, Four Seas Concentric” 2nd Multidisciplinary Forum on New Crown Pneumonia, the American Academy of Microbiology, the University of Hong Kong virologist Jin Dongxuan pointed out that human coronavirus infection has a certain seasonality, the new coronavirus is not seasonal is not known, but there is this possibility.
“At present, from the outbreak area, Wuhan, South Korea, Daegu and other places, relatively cold, dry, such as Malaysia, Singapore, such as a relatively high temperature, relatively humid places have not occurred community outbreaks, is not a regular, need epidemiologists to do some research, in order to clean the coronavirus and temperature, humidity has no relationship.” Jin Dongxuan said.
A virologist expressed the same view: “From a local perspective, the new coronavirus will be affected by temperature, humidity and other climatic conditions; At present, the world is a pandemic state, want to control the outbreak through temperature rise, there is little hope. “
The virologistsaid said that when compared to temperature and humidity, the temperature will have a greater impact on the new coronavirus. But now there is no strict experimental data to support, in the end how much impact, whether it can play a decisive role, there is no rigorous conclusion.
Instead of relying on “weather”, it’s better to rely on yourself.
Michael Ryan, executive director of the World Health Organization’s Health Emergency Programme, has said that it is important to assume that the new coronavirus will remain capable of transmission in the summer, and that countries must act quickly and not expect the new coronavirus to disappear on its own in the summer, like the flu virus.
At present, Singapore, Malaysia, Brazil and other tropical countries are increasing the number of confirmed cases, Qi Xin said that under the current circumstances, only strict control can reduce the spread of the virus.
“If the correlation between viruses and climate is to be explored, the study process should take into account not only the climatic conditions, but also the impact of policy measures. This is a more complex system engineering, and climate impacts account for only a fraction of it.” Zixin said.
This is also the case with a paper by the Mauricio Santillana research team at Boston Children’s Hospital on the preprinted website medRxiv: without extensive public health interventions, weather changes ,such as increased temperatures and humidity in the northern hemisphere spring and summer, do not necessarily reduce the spread of the new coronavirus.
Therefore, to stop the spread of new coronavirus on a global scale, more rely on strong prevention and control measures, not because of rising temperatures and relax their vigilance.
“The impact of climate change on population health has significant geographical characteristics. In developing countries such as South Asia and Africa, people’s ability to cope with the economic and social and health impacts of climate change is relatively weak. New coronary pneumonia has been rampant around the world, and the international community should pay attention to the possibility of pandemics in developing countries and whether the spread of the new coronavirus in these countries is more significant lysed to the climate. Qi Xin stressed.