Will overseas strains trigger a new epidemic? How to monitor the import of strains? How many XBB infections are there in my country? China CDC responds

On January 13, at the press conference of 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 in more than a year since the discovery of the Omicron variant, the world has found that the strain has evolved into more than 750 evolutionary branches. As of January 10, in the global new coronavirus sharing database, the top two strains in the world are BA.2.75 and BQ.1.1. As of January 10, 72 recombinants of the Omicron variant have been found worldwide, among which XBB and its subbranches are the main ones. This variant accounts for a high proportion of the new coronavirus infected population in some countries. XBB.1.5 is a subbranch of XBB, and its transmission advantage has further increased. As of January 12, XBB.1.5 has been monitored and found in at least 40 countries and regions.

Chen Cao said that from December 1, 2022 to January 10, 2023, China has monitored and discovered 19 Omicron evolutionary branches from infected cases in 31 provinces and the Xinjiang Production and Construction Corps, among which BA.5.2 and BF.7 have an absolute advantage, and the two together account for 97% of these 19 evolutionary branches.

Since October 2022, China has reported 16 local cases of XBB, all of which are evolutionary branches of XBB.1. So far, no local cases of XBB.1.5 have been detected.

**** Chen Cao said that from December 1 last year to January 12 this year, China only monitored one local XBB infection case. As for imported cases, from December 1 last year to January 12 this year, 33 imported cases of XBB and its subbranches were monitored, and they came from 20 countries and regions. From the perspective of import risk, in the future or for a period of time, China faces the risk of importing XBB and its subbranches, which will cause a high risk of local related cases. However, according to the data monitored in our country, XBB has not formed a local epidemic. According to current research data, although XBB has a strong transmission ability, the symptoms produced after infection with XBB are similar to those of other Omicron strains, and the pathogenicity has not increased significantly.

Since October 2022, my country has detected 56 cases of local BQ.1, including 6 evolutionary subclades such as BQ.1, BQ.1.1, and BQ.1.2. In addition, since December 1, 2022, the national imported case monitoring data shows that 79 Omicron evolutionary subclades have been imported into my country, among which the top three with relatively high proportions are BA.5.2, BF.7, and BQ.1.1.

BQ.1 and XBB variants were introduced into China

Will it trigger a new round of epidemic?

BQ.1 and XBB variants have become the dominant strains in some countries. Once introduced into China, will they trigger a new round of epidemics? Chen Cao said that many people who have just experienced the new coronavirus infection may have sore throat, fever, cough, and even general discomfort. In fact, these are all responses of the human immune system to the new coronavirus infection. In the short term or for a considerable period of time, the immune system has immune memory to the infection of the new coronavirus. This memory is reflected in the fact that the human body can produce high levels of neutralizing antibodies and immune memory cells. In this case, even if a new Omicron variant appears, the possibility of causing a large-scale local epidemic is extremely low. However , for some vulnerable groups, high-risk groups (such as people over 65 years old), patients with underlying diseases, and people who have not been vaccinated, they may be infected or even infected again due to the introduction of new Omicron strains.

Chen Cao reminded the public: Don't underestimate it or panic. At this stage, personal protection is still necessary, especially for families with elderly people living together. They must pay attention to environmental hygiene, disinfect their hands, ventilate frequently, and be cautious about gathering. In addition, they must pay attention to their work and rest schedules and maintain a good attitude. "While we are responsible for ourselves, we are actually protecting the people around us," said Chen Cao.

my country has set up surveillance posts at multiple ports

Monitoring the evolutionary branches of the internationally prevalent novel coronavirus

Chen Cao introduced that although my country has cancelled the centralized quarantine measures after the new coronavirus was infected with "Class B and Class B", the disease control department and the customs department still monitor the import of new strains, and the monitoring of incoming personnel is still the first checkpoint for virus mutation monitoring. my country has set up monitoring sentinel points at many ports across the country, especially monitoring important evolutionary branches prevalent internationally, and conducting real-time risk assessments. If it is found that the import of strains is clustered in time, space and population, an early warning will be issued in a timely manner, and after risk assessment, certain prevention and control measures will be taken.

In addition to port monitoring, sentinel hospital monitoring is the second checkpoint to prevent the introduction of new strains and the resulting widespread spread. According to the national monitoring plan for new coronavirus variants, a certain number of sentinel hospitals have been established in 31 provinces (municipalities, autonomous regions) and the Xinjiang Production and Construction Corps. Sentinel hospitals are required to collect samples from new coronavirus patients every week and send them to local CDCs for whole genome sequencing of the new coronavirus, and send the data to the Institute of Viral Diseases of the Chinese Center for Disease Control and Prevention in a timely manner. The Chinese Center for Disease Control and Prevention will analyze the data and provide timely feedback. If new strains, important variants, especially those that can cause more severe illness and death, are found, the Chinese Center for Disease Control and Prevention will issue warnings and take measures in a timely manner.

As the Spring Festival approaches, the number of people returning home is gradually increasing. Chen Cao reminded people entering the country recently that if they feel unwell upon entry, they should report it in time and cooperate with customs officials to actively carry out sampling; if they feel unwell after entering the country, especially if they have fever symptoms, they must promptly carry out nucleic acid and antigen tests for the new coronavirus and seek medical treatment in time.

Source: Beijing Daily WeChat Official Account