Why does the concept of the close linker change? Can high temperature inhibit the spread of the new coronavirus? What the experts say
Our reporter Ye Qing
Why is the past concept of close contact for patients with new coronary pneumonia no longer applicable?
What is the impact of the change in the concept of close contact on the epidemic prevention and control measures?
Can the spread of the new crown virus be suppressed in the summer of high temperature and humidity?
The reporter recently interviewed relevant experts for this.
The concept of the close contact needs to be changed
During this time, epidemics occurred in many parts of the country.
At the recent press conference of the Joint Prevention and Control Mechanism of the State Council, Mi Feng, spokesperson of the National Health Commission and Deputy Director of the Propaganda Department, introduced that the current spread is mainly the Delta mutant strain, which has a fast spreading speed, The characteristics of fast replication in the body and long time to turn overcast pose greater challenges to prevention and control work.
The Guangzhou epidemic in May this year was the first "head-on confrontation" between my country and the Delta mutant strain.
"We found that the epidemic spread very quickly. In the early stage, 5 generations of transmission occurred within 10 days, with a transmission index of 4.04-5.0. According to this index, if effective measures are not taken, according to model predictions, there will probably be Guangzhou in the same period. 7.3 million people were infected.” On July 31, Zhong Nanshan, an academician of the Chinese Academy of Engineering, said when attending a summit event in Guangzhou, “Because the delta mutant virus has a high load, strong infectivity, and a high concentration of the virus breathed out by the infected, etc. Characteristic, the past concept of close contact is no longer applicable."
"The concept of close contact in the past was that the family members of the infected person, colleagues in the same office, and those who had meals and meetings within 1 meter of the infected person were all close contacts. For the delta variant, in the same space and in the same space. The unit and the same building that had been with the infected person 4 days before the onset of illness were all close contacts. Because of the change in concept, we formulated different control modes such as closed and closed control." Zhong Nanshan said, "According to the change of concept The number of close contacts increased from 378 to 5992. Through screening, some infected people were found, the source of infection was quickly identified, and the chain of infection was cut off."
After several adjustments to the prevention and control plan, since June 19, there have been no new infections in the Guangzhou community.
From the beginning of the epidemic to the realization of continuous "zero new additions", it took less than one month.
The new coronavirus can spread in all climates
Is the hot and humid summer the nemesis of the new coronavirus?
After all, SARS, which is in the same family as the new crown virus, quietly left the scene before the arrival of the intense heat.
However, this rule does not seem to be applicable to the new coronavirus.
As early as May last year, the well-known journal Science published a paper by researchers from Princeton University in the United States, stating that the northern hemisphere is approaching summer, and rising temperatures are unlikely to significantly inhibit the spread of the new crown pneumonia epidemic.
The research published by the Fudan University School of Public Health team in the European Journal of Respirology shows that from the perspective of the spread in Chinese cities, climate factors such as temperature and ultraviolet radiation have not had a significant impact on the spread of the new coronavirus.
This epidemic pattern is similar to Middle East Respiratory Syndrome (MERS). When the temperature exceeds 45 degrees Celsius, the number of MERS cases is still increasing.
From the point of view of the global occurrence area of the new crown virus, it has been proved that the new crown virus has the ability to spread under various climatic conditions, including the simultaneous epidemic in the northern and southern hemispheres.
The World Health Organization has also stated that from the evidence obtained so far, the new crown virus can spread in all areas, including areas with hot and humid climates.
Regardless of the climatic conditions, people must take protective measures if they live in or travel to areas where COVID-19 has been reported.
"Influenza viruses and new coronaviruses are not transmitted in exactly the same way." Cai Weiping, chief expert at the Infectious Diseases Center of the Eighth People's Hospital of Guangzhou, pointed out that influenza viruses are mainly transmitted through the air and are more easily affected by temperature. Therefore, influenza generally occurs in winter and spring and summer. Rarely; but the new coronavirus is spread by respiratory droplets, which is less affected by temperature.
He also pointed out that temperature is not the key to determining the prevalence of the new coronavirus. The prevalence of the virus is related to the intensity of prevention and control in the country and region.
"Although Delta has strong transmission power, its transmission route has not changed much. Respiratory transmission is still the main route, and contact transmission is the secondary route." Cai Weiping emphasized that wearing masks and vaccinations are important ways to deal with infectious diseases. .
After the human body produces antibodies through the vaccine, even if it is infected with the virus, it can greatly reduce the probability of becoming severe and critically ill.