Once temperatures rise, will the new coronavirus recede?

Why spring may indeed be a boon Why do women have a clear advantage in fighting off viral attacks?

The website of Deutsche Welle Radio interviewed Thomas Pichmann, a molecular virologist at the Center for Experimental and Clinical Infection Research in Hanover, Germany, on these questions and published a report on March 1 titled "Cold, hot, dry, wet - what are viruses really afraid of? in the March 1 issue. The article is excerpted below.

Many people expect the arrival of spring to make the situation better. If the new coronavirus is really similar to the flu virus, it might be good news. If so, as spring arrives and temperatures rise, the virus will be killed and the outbreak will dissipate. But these are still just good intentions. Virologist Thomas Pichmann admits that the question of whether the new coronavirus will be as people expect it to be is strictly unanswerable, because humans do not know enough about this virus.

▲ The Louvre Museum in Paris was not open to the public on the 1st due to the New Coronavirus outbreak. This is a file photo of the Louvre in Paris, France, taken on March 11, 2019. (Xinhua News Agency reporter Gao Jing)

The special thing about this virus is that it is the first time humans have been exposed to it," Pichman said. Based on the data we got from China, we can conclude that this virus was transmitted from some kind of animal to humans, just that once, and then it spread and spread from there."

In other words, unlike the influenza virus to which almost everyone has been exposed, our immune system is not prepared for the invasion of the new coronavirus.

In addition, the current climate conditions in the Northern Hemisphere are "perfect" for the rapid spread of the virus. First of all, it is the temperature, the respiratory transmission of the virus is particularly active at lower temperatures: "The virus is more stable at lower temperatures. It's like food that can be stored longer in the refrigerator."

For many viruses, the warmer the temperature, the worse the day. "The new coronavirus is encased in a lipid layer," Pichman said. The lipid layer is not particularly heat-resistant, so the virus is killed quickly at elevated temperatures. "Some other viruses, such as noroviruses, are much more stable because they are composed mostly of proteins and genetic material."

For other pathogens, temperature isn't as important. Dengue fever viruses, for example, are most common in tropical and subtropical regions. It's not that the dengue virus is particularly fond of warm environments, but more importantly that the host of this virus, the mosquito, prefers to live in hotter places. In this case, temperature does not play a major role in the spread of the pathogen, but rather the animal carrying the virus," Pichman said.

▲ An AC Milan supporter walks outside the San Siro Stadium in Milan, Italy, on March 1. A sign at the stadium shows that AC Milan's match against Genoa is postponed to May 13. (Photo by Alberto Lingria, Xinhua News Agency)

Humidity also plays a major role in the contagiousness of respiratory viruses. Pathogens are sent floating outside the body after a person sneezes violently. Pittsman said, "Tiny droplets with viruses stay in the air longer in most drier, cold winter days than in high humidity environments." Pittsman said.

Pathogens get spread quickly this way. However, they keep a "low profile" in the initial stages. From the end of the first exposure to the pathogen to the first symptoms often take several weeks. The length of this incubation period is related to the characteristics and biology of the virus.

The typical symptoms of viral infection are fever, pain and chills, which are signals that the muscles are fighting the invader. The success of this battle is not only related to the age and health status of the infected person, but also depends on gender. In the New Crown epidemic, one can also learn from the data that women are significantly more likely to survive than men: the mortality rate for men is 2.8%, significantly higher than the 1.7% for women.

▲ Shopkeepers wear masks for business at a store in Baghdad, the capital of Iraq, on Feb. 29. (Photo by Khalil Dawood, Xinhua News Agency)

Pichman said, "There are genetic reasons for this on the one hand, because some genes related to the immune system, such as those responsible for recognizing pathogens, are encoded on the X chromosome." Because women have two X chromosomes, compared with one in men, women clearly have an advantage in this regard.

Estrogen can also help women fight off viruses, he notes: "Some genes associated with immunity also have binding sites to estrogen, meaning that these genes can be regulated by hormones."

Perhaps when spring blooms in the northern hemisphere, the new crown epidemic will indeed be over.