What you need to know about the Kraken Covid variant

Since Omicron has become the world’s dominant variant of Covid, it takes many forms. First there was BA.1, then BA.5 and finally others including BQ.1 and BQ.1.1. Now all eyes are on another encrypted string of letters and numbers, XBB.1.5, also known as Kraken, which has swept the northeastern United States in recent weeks.

The World Health Organization (WHO) has recognized the XBB.1.5 as the most transmitted version of the Omicron variant to date and announced that countries should consider recommending masks in risky situations such as flying. It is fast becoming dominant in parts of the US, and some experts are concerned it could bypass immunity from past infections and possibly vaccines.

Every time a new option comes up this fast, it grabs attention. Significant variations in the SARS-CoV-2 virus could lead to more illness, hospitalizations and deaths, which could overwhelm healthcare systems and increase the number of lingering Covid-19s. While XBB.1.5 infections are on the rise, the WHO says there is no evidence that mutations in this variant will lead to more severe infections, but it’s still early. In the US, Covid hospitalizations are tick up, but far from their early 2022 peaks. However, the emergence of a rapidly expanding variant brings back attention to a persistent problem: how vaccines should be updated.

“We haven’t seen a sublineage that has evolved at this rate for some time now, so this is another sign that it might be worth watching,” says Pavitra Roychaudhuri, director of Covid-19 sequencing at the University of Washington Virology. . Roychaudhury’s lab says it’s important to see options early on to identify them and think about how to develop future vaccines: , which is likely to circulate at a high frequency.”

This variant is a recombinant subline of the other two branches of Omicron. Such mixing can occur when a person is infected with two variants of the virus at the same time or if they are found in sewage.

This one could stand out among several circulating Omicron variants if it turns out to have two advantages that would make it highly contagious: the ability to evade antibodies from past infections or vaccinations, and the strength to bind to the ACE2 receptors through which Covid enters cells. and infect people. AND preprint published in early January by Chinese researchers specializing in XBB.1.5 claims that this is the case, but this paper has not yet been published or peer-reviewed.

“It’s kind of a mutation double whammy,” says Peter Hotez, co-director of the Texas Children’s Hospital Vaccine Development Center and dean of the National School of Tropical Medicine at Baylor College of Medicine. “Not only does it have the ability to evade the immune response, but it was able to do so while retaining the ability to bind to the receptor.”

It’s also spreading faster due to people’s behaviour, with few wearing masks compared to 2020 and many traveling and gathering indoors to celebrate the holiday season. This is a recipe for many people who get sick quickly. “What we have right now is this sub-option that has a lot of immune escapes that also come into play when we have pretty much taken out most, if not all, of our other public health mitigation methods,” says Stephanie Silvera is an epidemiologist and professor of public health at Montclair State University in New Jersey.