China CDC Detailed Explanation CH.1.1: No increase in pathogenicity will not cause a large-scale local epidemic in the short term

　　Chinanews.com, Beijing, February 1 (Wei Xianghui) A few days ago, a variant of Omicronia called CH.1.1 appeared in the United States.

On January 31, the China Centers for Disease Control and Prevention answered relevant hot issues.

Data map.

Photo by Yin Liqin

No enhanced pathogenicity of CH.1.1 mutant strains

　　According to the China Center for Disease Control and Prevention, CH.1.1 belongs to the sixth-generation subclade of the Omicron mutant strain BA.2.75.

The latest research shows that due to the addition of multiple mutation sites, the immune escape ability of CH.1.1 is increased.

At the same time, a newly added mutation site (L452R) was once a characteristic mutation site of the delta variant.

However, it is worth noting that this mutation site also exists in many other subclades of Omicron mutant strains, such as BA.5.3 and BA.5.1.3.

　　From November 2022 to the present, the proportion of CH.1.1 among the epidemic strains of the new coronavirus in the United States is on the rise.

In the fourth week of 2023, the proportion of CH.1.1 strains prevalent in the United States is the fifth, second only to XBB.1.5, BQ.1.1, BQ.1 and XBB mutant strains.

　　At present, there is no enhanced pathogenicity of the CH.1.1 mutant strain, and further attention is still needed.

Generally, after a new strain emerges, the infection cases need to reach a certain scale and last for a period of time before we can initially judge whether the pathogenicity of the new strain has changed.

Data map.

Photo by Yin Liqin

It will not cause a large-scale local epidemic in the short term

　　According to the China Centers for Disease Control and Prevention, on November 13, 2022, my country detected the CH.1.1 evolutionary branch for the first time from a sample of imported cases from Thailand (sampled on November 10, 2022) reported by Tianjin through genome sequencing.

As of January 30, 2023, a total of 24 imported cases of CH.1.1 and its subclades have been detected.

The source of imported cases involves 15 countries or regions.

Indigenous infection cases of CH.1.1 and its subclades were not detected.

　　According to the Chinese Center for Disease Control and Prevention, although the immune escape ability and transmission advantages of the CH.1.1 mutant strain have been further enhanced, leading to an increased risk of breakthrough infection and reinfection, most people in my country already have high levels of neutralizing antibodies, which are resistant to CH.1.1. There is a certain cross-protection effect, and CH.1.1 will not cause a large-scale local epidemic in the short term.

Vulnerable groups (the elderly over 65 years old, patients with underlying diseases and those who have not been vaccinated) and uninfected groups still need to strengthen personal protection.

　　How to face CH.1.1?

China CDC stated that adhere to personal protection, maintain good hygiene habits, and do not believe unconfirmed Internet reports.

Data map.

Photo by Yin Liqin

At present, BA.5.2 and BF.7 are the main epidemic strains in this round of epidemic.

　　On January 30, at a press conference held by the joint prevention and control mechanism of the State Council, Chen Cao, a researcher at the Institute of Viral Diseases of the Chinese Center for Disease Control and Prevention, introduced that the report shows that the current prevalent strains are mainly BA.5.2 and BF.7.

　　He said that since the outbreak of the new coronavirus infection, our country has been carrying out the monitoring of the mutant strain of the new coronavirus, which has also provided important clues and support for the traceability of the early epidemic situation.

At the same time, this process has accumulated a lot of experience and data.

According to the monitoring data, BA.5.2 and BF.7 are the main epidemic strains in this round of the epidemic, and no other dominant virus strains have been detected in my country so far.

　　In addition, during the Spring Festival holiday, the China Centers for Disease Control and Prevention received 1,421 genome sequences of the new coronavirus reported by various provinces across the country. After analysis, it was found that they had 11 evolutionary branches, still dominated by BA.5.2 and BF.7, and no new ones were found. Mutant strain input.

　　Chen Cao mentioned that the current Spring Festival travel season is underway, and colleges and universities will start school one after another in the near future. In the next step, we will continue to guide the country to do a good job in monitoring the mutation of the new coronavirus, and continue to monitor outpatient (emergency) cases, severe cases, Death cases and special populations carry out mutation monitoring of the new coronavirus.

At the same time, together with other departments, we will monitor the mutation of the new coronavirus for the entry personnel at sea, land and air ports, give timely warning and take corresponding prevention and control measures.

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