Can the high temperature in summer restrain the Covid?
(Compiled by Health Times reporter Jing Xuetao) According to the latest statistics of the new crown epidemic released by Johns Hopkins University in the United States, as of 8:32 on May 20, Beijing time, a total of 4,893,195 cases have been diagnosed globally, with deaths 322,861 cases. As can be seen from the epidemic map, the current global epidemic is mainly distributed in subtropical and tropical regions. Previously, there was a saying that the new coronavirus is not resistant to high temperature weather. Now that summer is here, can the epidemic really improve with weather?
May 19th, Beijing time, "Science" magazine published a research result from the research team of Princeton University. Scientists used the model to simulate the impact of weather changes on the spread of the new coronavirus, and found that compared to factors such as temperature and humidity, the most important thing is the immunity of the population, pure hope that summer is not reliable.
The researchers simulated a global pandemic, and focused on picking out nine cities with very different average humidity and seasonal cycles. It should be noted that only climate and season factors are considered here, and population density, prevention and control measures, and other complex environmental factors are not included.
Judging from the simulation results, even in the northern hemisphere, even if the climates in New York, London and Delhi are very different, there is no difference in the scale of the pandemic. In the tropics, the epidemic lasts longer and has a lower intensity than the northern hemisphere. This may be due to the relatively high humidity in the tropics, so there will not be a high spread rate like in high latitudes, but the outbreak is still very serious.
Compared with the northern hemisphere, although the seasonal changes are different by six months, the peak disease epidemic has only a slight delay.
In addition, the epidemic peak is not affected by the duration of immunization, but the later outbreak time point is related to it.
For new infectious diseases, population susceptibility is an important driving force for transmission, so the researchers also simulated the prevalence of different population susceptibility levels in specific geographic locations. It can be seen from the result chart that even though specific humidity is an important influencing factor, the influence is still far less susceptible than the crowd. Even if non-pharmacological methods are adopted, a large number of cases will still be caused by high susceptibility after summer. The susceptibility of the population is far beyond the climate (left). The prevention and control measures still cannot block the large number of cases caused by high susceptibility (right). From the simulation results, it is seen that the key to reducing the peak incidence is whether the population immunity in prevention and control To what extent has it been enhanced, the ability of climate to regulate and control is complex and limited. What is important is the timing and intensity of the introduction of prevention and control measures, and a thorough serological survey of the population.
In terms of the results of this study, population immunity is the fundamental driver of the new crown epidemic. Tropical and temperate regions should be prepared for serious outbreaks of disease, and high temperatures in summer cannot effectively limit disease transmission. Climatic factors can be used to predict the epidemic cycle of the disease and develop appropriate prevention and control measures.