Chinanews.com, Beijing, January 3rd (Wei Xianghui) Recently, the XBB.1.5 branch of the Amicron subtype has attracted widespread attention.

At present, Shanghai has discovered the XBB.1.5 strain in the monitoring of imported cases abroad.

　　On the 2nd, according to the Xinmin Evening News, in response to Shanghai citizens’ concerns about the introduction of the European and American strains BQ. .1 and XBB strains were only detected in a very small number of quarantined persons entering the country, and have not yet caused local transmission in society.

　　Relevant experts told Chinanews.com that there is no need to worry too much about the pathogenicity of XBB.1.5 and the risk of secondary infection.

During the New Year's Day holiday, fever sentinels in some communities in Shanghai are open to facilitate citizens' medical treatment. China News Agency reporter Yin Liqin

XBB.1.5 may become the main virus strain in the world in a short time

　　According to The Paper, the Global Initiative to Share All Influenza Data (GISAID) database added 369 new sequencing results of the new coronavirus in China, uploaded by a joint research team led by Chen Saijuan from Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine and Fan Xiaohong from Shanghai Public Health Clinical Center Tackling team.

　　These samples came from patients with new crowns in Shanghai. They were randomly collected from November 23 to December 22, 2022. Gene sequencing confirmed 30 known subtype strains of Omicron, and no new variants of the new coronavirus have been found.

In addition, among the 25 XBB families monitored in Shanghai this time, there were 3 cases of XBB.1.5, which were also imported cases from abroad and did not cause local transmission.

　　The researchers said that the virus strains in patients imported from abroad are relatively complex, and most of them were detected for the first time in my country.

The current sequencing results show that there are many new virus strains imported from abroad, and routine detection of virus strains is still needed to provide a basis for subsequent scientific prevention and control.

　　According to reports, experts at home and abroad predict that XBB.1.5 will become the main virus strain in the world in a short period of time and needs to be closely watched.

Another important reason is that the human ACE2 binding affinity of XBB.1.5 is almost equivalent to that of BA.2.75, which may allow XBB.1.5 to acquire more mutations like BA.2.75 in the future. Not going to evolve anytime soon.

Medical staff from the Songjiang Branch of Shanghai First People's Hospital conduct pre-examination for patients.

Photo by Yin Liqin

What is the pathogenicity of XBB.1.5?

　　According to media reports, previously, data released by the US Centers for Disease Control and Prevention on December 30, 2022 Eastern Time showed that it was estimated that 40.5% of new coronavirus infection cases in the United States that week were caused by the XBB.1.5 strain.

Scientists also said that due to its extremely high "immune escape" ability, XBB.1.5 has replaced BQ.1.1 and BQ.1 as the number one epidemic strain in the United States.

　　Studies have shown that the immune escape ability of XBB.1.5 is comparable to that of XBB.1, but the key mutation F486P makes it have a higher human ACE2 receptor binding affinity-ACE2 can be regarded as the "gate" for the new coronavirus to enter human cells, This means that XBB.1.5 is more likely to infect the human body.

　　In this regard, Jin Dongyan, a professor at the School of Biomedical Sciences of the University of Hong Kong and an expert in virology, introduced to Chinanews.com that while F486P slightly increased its ability to bind to ACE2 receptors, its immune escape ability was also slightly weakened.

This again shows that replication infection and immune escape are linked.

The change now is genetic drift, that is, the phenomenon of occasional changes that cause the gene frequency of the next generation to be different from that of the current generation, without actually moving too far from the baseline.

　　Jin Dongyan said that XBB.1.5 has not caused significant changes in the number of infections, hospitalizations, and deaths in the United States so far, so there is no need to worry too much about its pathogenicity and secondary infection risks.

"Except for the enhanced immune escape ability to a certain extent, the changes in other aspects are relatively small." He said.

During the New Year's Day holiday, grassroots medical staff are still fighting on the front line Photo by China News Agency reporter Yin Liqin

Can medical institutions cope with new strains?

　　On January 1 this year, according to CCTV's "Face to Face" program, in early December 2022, many cities began to experience a peak of new coronavirus infections, and the number of infected patients soared, and the fever clinics in hospitals were the first to come under pressure.

　　Regarding whether XBB.1.5 will cause a new round of infection peaks in mainland China, Professor Zhang Jiming, deputy director of the Infectious Diseases Department of Huashan Hospital affiliated to Fudan University, responded to Chinanews.com: "There is no need to worry, it is a bit exaggerated."

　　Zhang Jiming said that the new strains currently monitored still belong to the Omicron subtype, which is still a respiratory virus, that is, it mainly infects the respiratory tract, and its pathogenicity has not increased.

At the same time, combined with the experience of dealing with the first wave of infection peaks, medical resources can cope.

　　Jin Dongyan also said that the emergence of XBB.1.5 in the United States has not changed the basic situation of the new crown entering the endemic epidemic in the United States.

In his view, there is no soil for a tsunami-like outbreak of the new crown in the United States at present. XBB.1.5 has not changed this soil, and it has not caused a major outbreak similar to BA.2 at the beginning of the year in the United States.

(use up)