The highly transmissible JN.1 subvariant of the coronavirus is rapidly spreading throughout the United States, according to the Centers for Disease Control and Prevention (CDC). Estimates suggest that JN.1 is responsible for approximately 20% of new COVID-19 infections in the country, making it the fastest-growing strain. In the Northeast, it is even more dominant, causing around a third of new infections.
JN.1 is a descendant of the Pirola subvariant, also known as BA.2.86, which gained attention over the summer due to its numerous spike protein mutations. At the time, there were concerns that these mutations would render vaccines and antibodies ineffective, potentially leading to a surge in cases similar to what occurred with the original Omicron variant in 2021. However, such a scenario did not materialize, and BA.2.86 continued to circulate at a slow pace in some countries, including the US. It appeared that BA.2.86 may have lost some of its ability to infect human cells, preventing it from spreading widely.
Enter JN.1, which is two generations removed from BA.2.86. Although JN.1 has only one change to its spike protein compared to its ancestor, this single mutation seems to have made it a more fit and fast-spreading virus. The prevalence of JN.1 in the US more than doubled between late November and mid-December, likely aided by holiday travel and waning immunity.
Variant trackers anticipate that JN.1 will become the leading coronavirus variant worldwide within the next few weeks. Dr. T. Ryan Gregory, an evolutionary biologist at the University of Guelph, explains that JN.1 demonstrates a high level of competitiveness with other variants and is on track to become the next dominant group of variants globally.
The crucial mutation in JN.1's spike protein appears to enable the virus to evade our immune responses. Studies from Columbia University and researchers in China have suggested that antibodies may be about twice as effective at neutralizing this subvariant compared to others. While this decrease in neutralization capacity may not be significant, it could signify the potential for another wave of infections in the near future.
Several European countries, including Denmark, Spain, Belgium, France, and the Netherlands, have already witnessed exponential growth of JN.1, leading to a rise in hospitalizations. The subvariant is also spreading rapidly in Australia, Asia, and Canada.
In the United States, waning immunity due to low vaccination rates has contributed to the spread of JN.1. A significant number of Americans have chosen not to receive the latest round of COVID-19 vaccines, with vaccination rates comparable to last year. As a result, their immunity remains insufficiently updated to effectively combat severe COVID-19 infections.
The CDC has urged healthcare providers to redouble their efforts in promoting and administering COVID-19 vaccinations. They emphasize that it is not too late in the season to benefit from the shots. Furthermore, the CDC has raised concerns about the recent 51% increase in COVID-19 hospitalizations in the past four weeks. With hospitalization rates for influenza and respiratory syncytial virus (RSV) also on the rise, the strain placed on healthcare facilities could become overwhelming.
Fortunately, recent research from Dr. David Ho's lab at Columbia University indicates that the current COVID-19 vaccines, designed to enhance immunity against the XBB family of variants, also offer substantial protection against BA.2.86 and its offshoots, including JN.1. This finding strongly supports the recommendation to widely distribute the updated vaccines to safeguard public health.
The World Health Organization (WHO) echoed this sentiment, endorsing the upgraded COVID-19 vaccines as they provide broad protection against a variety of variants, including XBB.1.5.
Despite the availability of vaccines and antiviral treatments like Paxlovid, Dr. Alex Greninger from the University of Washington laments the decreasing uptake of boosters and antiviral drugs. It is disheartening when valuable tools against COVID-19 are underutilized, especially after the extensive efforts made to develop and distribute them.
In conclusion, the JN.1 subvariant is rapidly becoming the dominant strain of COVID-19 in the United States and globally. Its increased transmissibility and potential to evade immune responses pose a significant threat. The CDC and WHO emphasize the importance of wide-scale vaccination with updated vaccines to mitigate the impact of JN.1 and other variants. It is crucial for individuals to prioritize their health and the well-being of society by taking advantage of available preventive measures.