At present, the official number of confirmed confirmed cases of the new coronavirus exceeds 30,000, but in fact the number of people exposed to the virus far exceeds the number of confirmed cases, and most people have not developed the disease. Even after being diagnosed, some people quickly become severely ill, and some people have mild symptoms and heal quickly. In other words, in the face of the virus, some people have strong resistance, and some have weak resistance. The recent research results of scientists from the University of California, Los Angeles and the University of Arizona help to solve this problem that has plagued people for decades: Why does the same virus bring different effects to people? Even if infected with the same virus, some people’s conditions Very light, some are much worse?
Their research overturned a common concept that after previous exposure to influenza viruses, there is little immune protection against viruses transmitted from animals to humans. But the fact is just the opposite. Exposure to influenza viruses in childhood can protect people from viruses that are more distantly related to influenza viruses in later life.
Biologists refer to past exposure to influenza viruses as determining a person’s future response to infection, which is called the “immune imprint.” People’s ability to resist influenza virus depends not only on the subtype of influenza they have contracted in their lives, but also on the order in which they were infected by the virus. This finding can help provide a reference for strategies to minimize the impact of seasonal flu (First childhood flu helps explain why virus hits some people harder than others, Science Daily, 4 February 2020).
The study analyzed the effectiveness of travel-related screening for the new coronavirus 2019-nCoV. They found that screening travelers is not very effective for the 2019 coronavirus. On average, it can only detect less than half of the infected travelers. Most infected travelers cannot be tested. This means that they have no symptoms and are not aware that they have been infected. Therefore, passing airport or border inspections is not enough to stop the spread of the virus.
Professor Lloyd Smith of the University of California, Lowe, said: “This places the government and public health officials responsible for monitoring travelers after they arrive, quarantining them if necessary, and tracing people who are in close contact with them after they become ill.” Many The country’s government has begun to implement quarantine and even travel bans because they realize that screening is not enough to stop the spread of the coronavirus. Researchers, including scientists from the University of Chicago and the London School of Tropical Hygiene and Medicine, have developed a free online application that allows people to calculate the effectiveness of travel screening based on a series of parameters.
According to this study, the greatest risk of spreading the virus through international travel comes from those travelers who carry the virus, are immune to the virus, and have no symptoms or have very mild symptoms, because they will not be screened and it is easier Be ignored. Therefore, some countries implement a passenger registration system, which is considered to be more effective than border screening. In addition, some countries have different opinions on the suspension of direct flights to China. They believe that this will cause travelers to transit through third countries, especially through countries with weaker epidemic prevention capabilities, expanding the source of the virus and increasing the difficulty of monitoring.
