Singapore reopens "mobile hospital", is the new crown JN.1 strain worth worrying about?

On 15 December, Singapore's Ministry of Health (MOH) announced measures to deal with the new wave of the pandemic: it will change from weekly case data to daily case data from 19 December. In the first week of early December, according to data released by Singapore's Ministry of Health, the country recorded more than 56,000 new confirmed cases, a 75% increase from the previous week.

In order to better accommodate the infected, the Singapore Expo Cabin Hospital has also been reactivated to reduce the burden on the hospital and admit COVID patients who do not require intensive care. The mobile hospital was used to treat COVID patients in the early days of the pandemic in 2020 and was suspended in August of that year when the epidemic eased in Singapore. Currently in use is the 10th exhibition hall of the Expo Center, which can accommodate 40 beds and can be expanded in a short time.

According to Singaporean authorities, medical staff have been on standby and ready to be deployed to the field hospital.

JN.1 is raging around the world, and China is not at risk for the time being

At present, the vast majority of COVID cases in Singapore are caused by the COVID-19 variant JN.1, which is the second-generation subclade of the Omicron BA.2.86 variant of the new coronavirus and a subclade of the BA.2.86 variant with a strong transmission advantage, which was first detected in samples collected in Luxembourg on August 25 this year.

Compared to the previous generation BA.2.86, JN.1 has an additional spike protein mutation, L455S, which allows JN.1 to effectively evade class 1 neutralizing antibodies, allowing it to outperform its precursor BA.2.86 and popular variants XBB.1.5 and XBB.1, among others.

Because of this mutation, JN.1 quickly took over the mainstream of the new crown variant. On 21 November, WHO upgraded the BA.2.86 variant from a "variant requiring surveillance" to a "variant of concern". The CDC also included JN.1 separately in the new crown nowcast for the first time, and said that JN.1 is currently the fastest-growing new crown variant in the United States.

As of December 8, local time, the CDC estimated that the JN.1 variant accounted for about 15% to 29% of the circulating variants in the United States, while in the estimate on November 27, it accounted for less than 1%, and the proportion was less than 0.1% at the end of October. Such a ferocious speed of transmission surprised the CDC in the United States.

Surveillance data from European countries also show that the JN.1 variant is gradually dominating and increasing rapidly. As of mid-November, several European countries, including Ireland, Iceland, Portugal, Spain and France, have seen exponential growth, especially in Denmark, where infection with the variant has covered 50% of the population. With a projected weekly growth rate of 84.2%, JN.1 in the UK is spreading much faster than other known variants.

The situation in China is different from that in Europe and the United States. According to the Chinese Center for Disease Control and Prevention, the main circulating strains in mainland China at this stage are still EG.5 and its subclades. The local JN.1 variant was detected for the first time in the mainland in November, and as of December 10, a total of 7 cases of the JN.1 variant have been detected in the mainland.

However, the CDC also said that although the current prevalence level of the JN.1 variant in the mainland is extremely low, it is not ruled out that the JN.1 variant will become the dominant epidemic strain in China due to the subsequent impact of international epidemic strains and imported cases.

There was no increase in the severity of JN.1 pathogenicity

Although JN.1 is more contagious than its predecessors, there are also studies that show that it is less contagious.

A study by Cao Yunlong, a researcher at Peking University's Center for Biomedical Frontier Innovation, showed that although L455S significantly enhances the immune escape ability of JN.1, it reduces its ability to bind to the new coronavirus receptor ACE2. The CDC also said that there is currently no evidence that JN.1 poses a greater public health risk than other circulating variants, and there is no indication that it is becoming more severe.

The United States believes that there is no need to worry about JN.1 and instead encourages people to get vaccinated. Preliminary data suggest that the upgraded COVID vaccine will help prevent BA.2.86 and is also expected to be effective against JN.1, with previous testing and treatment measures continuing to be effective.

Lu Hongzhou, deputy secretary of the Party Committee and president of the Third People's Hospital of Shenzhen, said that domestic residents have generally experienced 2 or even 3 infections, and existing research data show that individuals have produced strong and broad-spectrum neutralizing antibodies against different submutant strains of Omicron. He speculated that the future epidemic of the JN.1 variant in China may lead to an increase in the number of new crown infection patients in the short term, thereby increasing the medical burden of hospitals, but it will not have much impact on the wave of respiratory disease infections that the country is experiencing.

Since December, five new crown vaccines have been approved for emergency use in mainland China, namely CSPC's new coronavirus bivalent mRNA vaccine, Shenzhou Cell's iterative recombinant new coronavirus variant S trimer protein vaccine, Walvax's new coronavirus variant mRNA vaccine (Omicron XBB.1.5), CanSino's inhaled novel coronavirus XBB.1.5 variant vaccine (adenovirus type 5 vector), and Livzon Pharmaceutical's recombinant new coronavirus fusion protein bivalent vaccine (CHO). cells).

In addition to more vaccines approved, in the just-concluded 2023 national medical insurance negotiations, three domestic new crown drugs: Simcere Pharmaceutical's Xiannuoxin, Junshi Biosciences' Mindewei and Zhongsheng Pharmaceutical's Leruiling have been officially included in the medical insurance list.

Written by Liang Jian Editor Jiang Yun Jia Ting

Operation|Han Jinrui

Source: Visual China