According to The Paper, recently, a joint scientific research team led by Chen Saijuan from Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine (referred to as Shanghai Ruijin Hospital) and Shanghai Public Health Clinical Center (referred to as Shanghai Public Health Center) Fan Xiaohong shared all influenza data for the world. The initiative (GISAID) database added 369 new sequencing results of the new coronavirus in China.

　　It is worth noting that among the 25 cases of the Omicron subtype XBB family that were monitored in Shanghai this time, there were 3 cases of XBB.1.5, all of which were imported from abroad, and did not cause local transmission.

However, recently, the new variant XBB.1.5 of Omicron has spread rapidly in the United States, attracting the attention of netizens.

So, what are the characteristics of this strain?

Is it more pathogenic?

Will it cause secondary infection?

　　XBB.1.5 that quickly "upgrades":

　　Originally discovered in New York, it has become the number one strain in the United States

　　In the Omicron family, the BQ series subtype strains belong to the BA.5 branch, and the XBB series strains that have attracted attention recently are recombinants of the BA.2.75 and BJ.1 sublines derived from BA.2.

　　According to CCTV news reports, in June 2022, the BQ.1 variant was first discovered in Nigerian infected persons.

In September, BQ.1 and its descendant sub-branches became popular in European and American countries, and the proportion increased month by month. In mid-October, it gradually became popular in Asian countries and regions such as Japan and Singapore.

　　In addition to the mutations found in BA.2, the XBB subvariant had 14 more mutations in the spike, 5 in the N-terminal domain (NTD) and 9 in the receptor-binding domain (RBD), while the XBB .1 There is an additional G252V mutation.

　　Subsequently, the Omicron subtype strain named XBB.1.5 was discovered in New York, USA, and quickly swept across the United States.

On December 13, 2022, the "Cell" magazine published online the latest research on the BQ and XBB families of the Aumicron subtype strains by the team of Colombian AIDS expert He Dayi.

The study found that the distance between the BQ and XBB series variants and Omicron BA.5 was farther than the distance between Omicron BA.5 and the original Omicron strain, and the degree of antigenic drift or transfer ( That is, the degree of variation) is comparable to the original Omicron strain.

　　According to overseas network news on January 1, according to NBC and other US media reports, the US Centers for Disease Control and Prevention stated that the new variant XBB.1.5 of Omicron is spreading rapidly in the United States. infected with this new variant, up from 20% in the previous week.

In the Northeast, about 75% of confirmed cases were infected with XBB.1.5.

　　Barbara Barbara, director of the division of respiratory viruses at the U.S. Centers for Disease Control and Prevention, said there was no indication that XBB.1.5 would cause more severe disease than other Omicron variants.

While COVID-19 hospitalizations are on the rise across the country overall, there is no increase in hospitalizations in the Northeast.

　　Compared to other Omicron strains

　　No indication that XBB.1.5 causes more severe disease

　　Recently, a screenshot claiming that the XBB.1.5 strain attacks the digestive system and recommends stockpiling drugs has been widely circulated. Norfloxacin and montmorillonite powder mentioned in the screenshot subsequently appeared on hot searches and sparked discussions.

　　According to CCTV news reports, Xu Wenbo, director of the Institute of Viral Diseases of the Chinese Center for Disease Control and Prevention, said that the pathogenicity of BQ.1 and XBB is not significantly different from other series of mutant strains of Aomecron, and the severe disease rate and mortality rate are higher than those of the popular BQ.1. And XBB countries are not added.

　　In this regard, Li Zhiling, deputy director of the Pharmacy Department of Shanghai Children's Hospital, also said in an interview with the media that some people infected with the new crown do have symptoms of vomiting and diarrhea, which usually resolve on their own within 1-3 days.

The more important thing to treat diarrhea is to prevent dehydration and water and electrolyte disorders. Montmorillonite powder should be used under specific circumstances. Blind use will add to the chaos, and it is unnecessary to hoard medicine.

　　According to the latest report on December 31, in the past two weeks, the average number of daily hospitalizations in the United States due to new crown infections has increased by 4.2%, reaching 42,324.

However, hospitalization rates in the Northeast, where XBB.1.5 is dominant, were not higher than in areas where other strains are dominant, said Barbara Barbara, director of the respiratory virus division at the U.S. Centers for Disease Control and Prevention.

Currently, there is no indication that XBB.1.5 causes more severe disease than other Omicron strains.

　　Or the most powerful strain of immune escape in history

　　However, the transmission ability may not change significantly

　　In addition to pathogenicity, whether the new strain can be protected by vaccine induction and natural immunity is also the most concerned issue.

　　Given that XBB.1.5 has the F486P mutation, which enables it to better bind to cells, it is easier than other strains to break through the body's immune defense system.

This is also confirmed by He Dayi's team's latest research on the BQ and XBB families of the Aomecron subtype strains.

　　The researchers compared people who received three or four doses of the original COVID-19 vaccine, those who received the Omicron booster vaccine after three doses of the original COVID-19 vaccine, and those who had a breakthrough due to the BA.2 or BA.5 strains after vaccination A blood sample from a sexually infected person.

The results showed that the neutralization ability of the new crown vaccine and the sera of previously infected persons to BQ.1, BQ.1.1, XBB and XBB.1 decreased significantly, and the neutralization titers against BQ and XBB were reduced by 13-81 times and 66- 155 times, but not completely immune to escape.

This means that the increase of subvariants such as XBB may further impair the protective efficacy of the current new crown vaccine, leading to a surge in breakthrough infection and reinfection.

　　The researchers also found that BQ.1 and BQ.1.1 spikes have the same binding ability to ACE2 as BA.4/5 through surface plasmon resonance (SPR) analysis.

However, the binding ability of XBB and XBB.1 spikes to ACE2 was slightly lower than that of BA.2, which may be due to the F486S and R493Q mutations at the top of the receptor binding domain (RBD).

The researchers concluded that the SPR analysis provided no evidence that the increase in the new variant was due to a higher ability to bind ACE2.

　　As a result, the BQ and XBB series have gradually become the number one epidemic strains in the world, which may be due to their stronger immune escape ability, rather than stronger transmission ability.

However, another study from the University of Washington's Institute for Health Metrics and Evaluation (IHME) also showed that the XBB variant was more contagious than earlier versions of Omicron.

　　Vaccination with different types of vaccine booster is better

　　Small molecule drugs are still effective

　　Despite this, the research of He Dayi's team also pointed out that the effect of the booster vaccine is slightly better than that of the original vaccine against the new Omicron subtype strain XBB.

Vaccination remains effective in preventing hospitalization and serious illness and may reduce the risk of sequelae, the researchers emphasize in the paper.

　　On December 31, Rick Bright, an American immunologist and former director of the Biomedical Advanced Research and Development Authority (BARDA), also pointed out in an interview, "In terms of XBB strain infection, Singapore's experience is encouraging." .

He said that in the previous wave of infections caused by XBB, although Singapore had a surge in infections, it did not see a corresponding large increase in hospitalizations and deaths. "We think this is because more people in Singapore have received the latest vaccines." and Omicron reinforcement needles."

　　This is also the "most important thing" agreed by many experts, that is, to receive a booster shot of the Omicron vaccine to enhance the immune system's ability to fight the new strain.

　　Previously, at the Second Greater Bay Area (Shenzhen) Vaccine Summit, Zhong Nanshan, an academician of the Chinese Academy of Engineering, pointed out in his speech that when talking about the booster injection after the full vaccination, after two doses of inactivated virus vaccination, the third dose of vaccine Effective and clinically protective enhancement demonstrated in the real world.

In addition, two doses of inactivated virus vaccines were followed by mRNA vaccines, two doses of inactivated virus vaccines were followed by subunit protein vaccines, and two doses of inactivated virus vaccines were followed by adenovirus vector vaccines. .

　　Zhong Nanshan clearly pointed out that vaccination with different types of vaccines may be more effective, but further observation of the protection rate in the real world is needed to confirm.

　　In addition, another issue worthy of attention is that the research of He Dayi's team also found that the monoclonal antibody is "basically inactive" against the new subvariant.

However, according to a study published in the "New England Journal of Medicine" on December 9, although monoclonal antibodies are ineffective against BQ.1.1 and XBB, only small molecule drugs targeting conservative targets remain effective.

　　Red Star News reporter Xu Huan