The WHO has singled out JN.1 as a new coronavirus variant that needs attention! Experts: It spreads quickly, but...

In view of the rapid spread of the new coronavirus variant JN.1 around the world, the World Health Organization released a preliminary risk assessment on December 19, listing JN.1 as a "variant of concern", but based on the currently available evidence, the additional risk posed by JN.1 to global public health is currently assessed to be low. The assessment report shows that JN.1 is a descendant lineage of the BA.2.86 lineage of the Omicron variant.

JN.1 was first discovered in Luxembourg in August 2023. The JN.1 variant of the new coronavirus is a sub-branch of the BA.2.86 variant. Global monitoring results show that after entering November, the global share of the BA.2.86 variant, especially the JN.1 sub-branch, has increased significantly and has become one of the dominant epidemic strains in some countries.

JN.1 has shown a higher infection rate

As of December 16, 7,344 JN.1 gene sequences from 41 countries have been uploaded to the Global Initiative on Sharing All Influenza Data (GISAID): 1,552 from France, accounting for 20.1%; 1,072 from the United States, accounting for 14.2%; and 934 from Singapore, accounting for 12.4%. The WHO said that from a global perspective, JN.1 has a significant transmission advantage over other popular variants, and its infection rate has rapidly increased from 3.3% in the week from October 30 to November 5 to 27.1% in the week from November 27 to December 3. During the same period, the prevalence of JN.1 in Singapore soared from 1.4% to 72.7%, and the prevalence in France also increased significantly from 10.9% to 45.5%.

The assessment pointed out that although JN.1 has shown a higher infection rate, growth advantage and immune escape characteristics, based on the existing evidence, the additional risk posed by JN.1 to global public health is low. With the arrival of winter in the northern hemisphere, it is expected that this variant may lead to an increase in new crown cases while other viral and bacterial infections surge.

The WHO said that compared with other Omicron sublineages, the spread of JN.1 is unlikely to increase the burden on countries' public health systems. Current vaccines can still prevent severe illness and death caused by JN.1 and other circulating variants. However, for countries entering winter, the new coronavirus and co-circulating pathogens may increase the burden of respiratory disease infections in general.

WHO is continuously monitoring the evidence and will update the risk assessment for JN.1 as needed.

According to the "News Hyperlink" of China National Radio and Television, the number of COVID-19 variant JN.1 spreading worldwide has increased significantly in recent times, causing concern.

Why is the proportion of JN.1 growing so fast? What are its advantages? What is the relationship between it and BA.5.2 and BF.7, which were prevalent in China at the end of last year? In addition to the new coronavirus, are there any new changes in the incidence trend of respiratory infectious diseases in the near future?

It's contagious, but not dangerous.

Li Dongzeng, chief physician of the Department of Infection at Beijing You'an Hospital, introduced that JN.1 is the second-generation sub-branch of the novel coronavirus Omicron BA.2.86 variant. From the current point of view, JN.1 in many countries accounts for an increasing proportion of newly infected people with the novel coronavirus. Gene sequence analysis found that the mutation site of JN.1 leads to a stronger ability to bind to human epithelial cells, so the infectivity and immune escape ability may be stronger than other strains, making the antibodies produced in the past unable to play a significant protective role. At present, there has been no significant increase in the pathogenicity of JN.1. Although it has led to an increase in the number of infections, there will be no significant changes in severe and critical cases.

Why is Omicron so changeable?

Li Dongzeng introduced that after the emergence of Omicron, it was BA.1 in early 2021, and BA.2 soon appeared in February and March. The later BA.4, BA.5 and XBB were all variants derived from BA.2. In the past year, my country and most other countries in the world have been dominated by XBB strains. The current JN.1 comes from BA.2.86, which are all variants of Omicron.

The ultimate goal of virus mutation is to have a greater advantage in transmission, which can also be understood as the survival of the fittest in virus transmission. Omicron has increased its immune escape ability through a large number of mutations on the S protein. The current incubation period has reached the limit of about 2 days, and has reached the ceiling in terms of transmission speed.

Although there are many types of mutations, Omicron has not changed much overall. Compared with the alpha, beta, and delta strains that were prevalent in the past two years, Omicron mainly replicates in the upper respiratory tract, and the symptoms it causes are mainly fever, cough, sore throat, nasal congestion, and runny nose in the upper respiratory tract. It has a short incubation period, fast transmission speed, and strong infectivity, but its pathogenicity has weakened, so there is no need to worry too much.

Low temperatures and cold waves kill viruses? False!

Li Dongzeng introduced that in the past week, the number of patients seeking medical treatment for respiratory infectious diseases has dropped significantly, and the peak of the epidemic has passed. At present, influenza is still the main cause, accounting for about 70%, mycoplasma is about 20%, and other pathogens add up to about 10%.

Some people believe that the recent cold snap is conducive to killing the virus. Li Dongzeng said that a sharp drop in temperature will lead to an increase in the number of people suffering from respiratory diseases. On the one hand, viruses are afraid of heat but not cold, and can be preserved for a longer time in a low temperature environment; on the other hand, after a low temperature, people's respiratory defense ability decreases, making them more susceptible to various respiratory pathogens. In addition, in a low temperature environment, residents are more willing to stay indoors, and fewer windows are opened for ventilation, which will increase the risk of gathering epidemics in places such as offices or schools.

Li Dongzeng reminded that although the number of cases is on a downward trend, there are still multiple pathogens that are prevalent. After being infected with a respiratory disease, it is still possible to be infected with other diseases. Therefore, it is necessary to take good protection. Once symptoms occur, stay at home and do not go to work or school while sick. When going out, especially taking public transportation or going to high-risk places such as hospitals and shopping malls, wear a mask, reduce the length of stay, and wash hands in time. When in contact with others, pay attention to coughing etiquette and maintain a reasonable social distance to reduce the risk of infection.

(Source: Jiemian News, China National Radio)