What is the prevalence of the new coronavirus variant KP.2 in China? Zhang Wenhong’s latest interpretation
Globally, a new coronavirus variant named KP.2 is spreading. Since February, due to the rapid increase in the proportion of KP.2 among global circulating strains, the World Health Organization listed KP.2 as a "mutant strain requiring monitoring" on May 3.
According to the information related to the KP.2 mutant strain of the new coronavirus released yesterday by the National Bureau of Disease Control and Prevention, as of May 12, a total of 25 KP.2 sequences have been detected in local cases in my country. The proportion of KP.2 in the weekly reported local series ranges from 0.05% to 0.30%, which is at a very low level.
The National Administration of Disease Control and Prevention stated that the top three major circulating strains in my country at this stage are JN.1, JN.1.16 and JN.1.4. On March 11, the KP.2 mutation was detected for the first time in local cases in Guangdong. strain.
KP.2 is the third-generation sub-branch of the new coronavirus Omicron JN.1 variant. It is also a sub-branch of the JN.1 variant with strong transmission advantages. It was collected in India on January 2, 2024. detected in the sample for the first time. There are no reports that the pathogenicity and immune evasion ability of KP.2 have significantly changed compared with the currently popular JN.1 variant strain.
Q2 What is the prevalence of KP.2 mutant strains internationally?
At present, the JN.1 mutant strain is still the dominant epidemic strain in the world. Since the beginning of this year, the proportion of the KP.2 subclade in the global epidemic strains has gradually increased, from 0.16% in early January to about 14% in early May. Recently, the prevalence of KP.2 sub-branch in some countries has been relatively high, accounting for 10% to 30%.
According to the latest data released by the US CDC, in the two weeks as of May 11, the KP.2 variant accounted for 28% of new coronavirus infections in the United States, compared with only 6% in mid-April.
The new coronavirus is continuing to mutate, but it is still difficult to break through the Omicron family. Just as influenza viruses continue to mutate, mutation is the norm for viruses to survive under host immune pressure.
The National Medical Center for Infectious Diseases combined data from 79 hospitals across the country and platform monitoring confirmed the mutation and fluctuation of the new coronavirus Omicron strain. From November 2022 to early April 2023, BA.5.2 and BF.7 are the main types. Since early April 2023, XBB classification has gradually increased. From July 2023, clinical sample classification will be mainly XBB classification, and EG .5 grew rapidly, with FY.3.1 and FL.13.2 newly discovered in early August. Among the mutant strains "needing attention" mentioned by the WHO, XBB.1.16 is more frequently detected. Among the mutant strains "under surveillance", XBB.1.9.2 and its subtypes will account for the majority in the second half of 2023. In August EG.5.1.1, the offspring of EG.5.1, was detected in late September, and HK.3, the offspring of EG.5.1.1, was detected in early September. The proportion of HK.3 gradually increased from September to December. The offspring of HK.3, HK.3.1 and HK.3.2, appeared in late October. JN.1 began to appear in January 2024, and the detection rate was above 70% from January to March. JN.1.1 and JN.6 appeared. For the equally divided type, as of April 30, JN.1 was still mainly detected.
The National Communication Center also tested underground sewage. The monitoring of the new coronavirus nucleic acid concentration in the sewage showed that there was a new crown peak around January 10, 2024, and then reached a peak infection plateau. Since March 27, there has been a downward trend. In April It has maintained at a level of 3*104 copies/L since mid-term, and the last sampling concentration on May 13 was 2.95*104 copies/L. There is a further downward trend, and this value is similar to the concentration in the interval between the second and third rounds of infection peaks.
During this period, the national clinical disease burden of COVID-19 did not fluctuate significantly and remained within normal fluctuations.
Current monitoring data suggest that the current epidemic of new coronavirus in my country is still dominated by Omicron JN.1, and the current international epidemic has focused on the descendant subtype KP.2 of JN.1. As of May 12, in our country A total of 25 KP.2 sequences were detected in the cases. The proportion of KP.2 in the weekly reported local series ranges from 0.05% to 0.30%, which is still at a very low level. Although there is still the possibility of an increase in the proportion of this subtype in the future, just as this subtype has been detected internationally since March this year, the US CDC monitoring indicates that as of May 11, the proportion of KP.2 has increased to 28.2% , but judging from the number of emergency visits, hospitalizations, and deaths, there is no obvious upward trend in the number of patients. Therefore, it can be judged that the actual subsequent clinical risk of KP.2 is limited.
In the future, we will still strengthen the surveillance of COVID-19 and other respiratory pathogens. The emergence of new virus subtypes will be the norm, and there is no need to worry too much.
