The Most Potent New COVID-19 Variant Strikes, Rapidly Spreading in 12 Countries Worldwide

On the 8th, the official website of the Centers for Disease Control and Prevention (CDC) in the United States for the first time included JN.1 in the SARS-CoV-2 Nowcast, describing it as the fastest-growing variant of the new coronavirus in the country. As of that day, the CDC estimated that the JN.1 variant accounted for approximately 15% to 29% of all circulating variants in the United States. In the estimation on November 27, its proportion was less than 1%, and at the end of October, it was less than 0.1%.

The CDC stated that they are still understanding JN.1 and investigating how it carries mutations to evade detection by the immune system.

Apart from the United States, the JN.1 variant has been found in 12 countries. Monitoring data on the COVID-19 situation in European countries also shows a gradual dominance of the JN.1 variant, with an upward trend. By mid-November, several European countries, including Ireland, Iceland, Portugal, Spain, and France, experienced exponential growth, particularly in Denmark, where the variant has infected 50% of the population. The UK also claimed that the weekly growth rate of JN.1 is expected to be 84.2%, significantly surpassing other known variants in terms of transmission speed.

As the JN.1 variant spreads, health authorities in the UK and the US claim it has become the fastest-growing known variant of the new coronavirus, potentially triggering a new wave of infections.

The World Health Organization (WHO) is currently monitoring this variant but has not designated it as a variant of concern (VOC).

This rapidly spreading variant was first discovered in Luxembourg in August this year. It still belongs to the Omicron lineage's subvariant. Moreover, it happens to be a descendant lineage of the highly transmissible Omicron subvariant BA.2.86.

The transmissibility of BA.2.86 had previously raised concerns and warnings from scientists in several countries. Scientists pointed out that, unlike previous variants, BA.2.86 has set a record for the number of mutations, surpassing 30, which means it might more easily evade current vaccine and antibody protections.

However, there is currently no indication that the severity of illness caused by JN.1 has increased, and there is no evidence suggesting an increased risk to public health compared to other currently prevalent variants.

Dr. Amesh Adalja, a medical doctor at the Johns Hopkins University Center for Health Security, stated that while attention should be paid to the JN.1 variant, "this is not something that has spread very widely or deeply," he said. "This is a very rare variant and is a branch of BA.2.86, but BA.2.86 has never really taken off."

However, Professor Sheena Cruickshank, an immunologist at the University of Manchester, believes that spike protein mutations indicate that patients infected with JN.1 may take longer to recover or may experience more severe disease.

In addition to the JN.1 variant, the highly transmissible HV.1 variant derived from Omicron is also spreading and has immune evasion properties, becoming the major viral strain in the United States. Dr. Chris Papaspyropoulos, Senior Lecturer in Public Health at the University of Bedford, said people need to pay attention to the symptoms of these two strains: those infected with the HV.1 strain may experience symptoms such as fever, cough, fatigue, nasal congestion, or runny nose. The JN.1 strain has similar symptoms, but infected individuals may also experience headaches and diarrhea.