The World Health Organization (WHO) warned on Tuesday of the rapid spread of the new JN.1 variant of the covid virus and noted that “with the arrival of winter in the northern hemisphere, JN.1 could increase the burden of respiratory infections in many countries.
It is the variant of the covid virus that is spreading most rapidly in the world. It was first detected in September and is on track to become the dominant variant globally. It is already the majority in Denmark, the country that most closely monitors the variants that circulate, and probably also in other countries, although they have not yet detected it.
Its most notable characteristic is its greater contagion capacity. The JN.1 is part of the large family of omicron variants, which emerged at the end of 2021 and has since displaced previous variants. The Omicron family itself has evolved in these two years. Since last winter, a variant called XBB.1.5 has predominated. A different variant called BA.2.86 emerged in the summer, which baffled virologists because it was not descended from the XBB lineage but from a more primitive version of omicron. Although it had more than 40 mutations compared to XBB.1.5, it did not have a large expansion as feared. JN.1 is an evolved version of BA.2.86 with much greater expandability.
The JN.1 variant has a single mutation compared to its parent BA.2.86. This mutation, called L455B, affects the S protein of the coronavirus, which is the protein that the virus uses to attach to human cells and also the protein that antibodies recognize. According to research from Peking University published in The Lancet Infectious Diseases, the L455B mutation allows the coronavirus to evade the immune system's antibodies.
Given that it is a recently emerging variant, “at this time it is not possible to know whether JN.1 (...) produces different symptoms than other omicron subvariants,” reports the American Medical Association (AMA) in a report on the new variant published on December 19. The AMA notes that “in general there have been similar symptoms between the different variants,” so it is to be expected that the symptoms will be similar. The most common include cough, sore throat, nasal congestion, tiredness, headache, muscle aches, and altered sense of smell.
Surprisingly, the booster doses that are being given this fall in Spain offer high protection against the JN.1 variant. These vaccines were designed against the XBB.1.5 variant. The fact that JN.1 has more than 40 mutations compared to XBB.1.5 raised fears that the vaccines would be ineffective. But three independent research teams (from Peking University, Washington University in Seattle, and Columbia University in New York) have shown that current vaccines significantly increase the levels of antibodies capable of neutralizing the JN.1 variant, reports epidemiologist Antoni Trilla, from the Hospital Clínic of Barcelona.
These antibodies have a limited effectiveness in preventing the virus from entering the body but a much higher effectiveness in neutralizing it once it has entered. Therefore, they are better at avoiding serious complications of covid than at preventing contagion. As highlighted by the American Medical Association, current vaccines help ensure that, if you contract Covid, the infection is mild and the symptoms do not last long.
The variants of the omicron family, of which JN.1 is a part, are characterized by being more contagious and less virulent than previous variants that predominated in the first waves of the pandemic. The immunity acquired thanks to vaccines and infections has contributed to significantly reducing cases of severe covid. But cases that require hospital admission continue to be recorded, almost all of them in people from vulnerable groups. Last year, 3,760 people died in Spain due to covid, according to data from the National Institute of Statistics. Therefore, people who are at higher risk of serious complications are advised to get a booster dose if they have not already done so.
The coincidence of the JN.1 variant, the Christmas holidays and the cold of winter suggests a significant increase in infections in the coming weeks, warns epidemiologist Antoni Trilla. To avoid becoming infected, and to avoid infecting others, the WHO recommends: wearing a mask in crowded, closed and/or poorly ventilated places; wash your hands regularly; cover your mouth and nose when you cough or sneeze; stay home if you are sick; and be up to date with vaccinations.
