Fast-spreading XBB1.5 variant signals new chapter in evolution of Covid-19, says University of Cambridge’s Prof Ravi Gupta
The emergence of the XBB1.5 variant of Covid-19 is a “good reminder that the virus is still changing” and the importance of keeping in top of vaccine uptake, a leading University of Cambridge virologist has said.
Ravi Gupta, professor of clinical microbiology at the Cambridge Institute for Therapeutic Immunology and Infectious Diseases, said the emergence of the highly transmissible and rapidly spreading variant may represent “a new chapter in the evolution of this virus” since it is the first radically new variant to emerge since Omicron in November 2021.
“XBB1.5 is really interesting, because it’s the daughter of a mixture of different viruses that have been circulating in humans in the last few months,” said Prof Gupta.
“So it’s actually what we call a recombinant. And it's had another couple of mutations added on top of it. And the reason it’s interesting is because it’s acquired a mutation that both enhances its ability to avoid the immune system, but also to latch on more tightly to ACE2, which is the receptor on our lung cells and our cells in our nose and throat that allows infection.”
Understanding where XBB1.5 - also called the Kraken variant - arose has been complicated by the massive drop in Covid sequencing worldwide, but XBB1.5 appears to be “taking over” from previous variants.
“I’m not necessarily worried about this because of course this is what will happen in terms of the virus and as long as we are well protected with vaccines, then this shouldn’t be a problem,” said Prof Gupta.
“In 2022 we saw a new vaccine with two different variants in and that has been shown recently to provide very good protection from hospitalisation and severe disease.
“So we believe that the vaccines we’re using are going to be highly effective against severe disease, as long as we are up to date on our boosters.”
He added: “I think that the XBB1.5 really is a good reminder that the virus is still changing.
It’s still doing things to avoid our immune systems and vaccines, and it’s still doing things to make itself more transmissible. And that's what you’d expect from an evolutionary process.
“And it just reminds us that really we do need to keep on top of our vaccination uptake, in other words, reaching vulnerable populations such as the elderly and those who are immune suppressed, as well as younger individuals with health conditions, and also just remembering that that masking is a highly effective way of preventing infection in crowded spaces and during winter, I believe that we should be maintaining such practices as we go forward and these are practices that are very common in Eastern countries.”
More variants are very likely, he said, particularly given the number of infections in China.
“We know now that new variants are generated in individual people over periods of months and even years of evolution. And these individuals usually have an immune system that can't deal with and can't clear the infection. So the the probability of that happening has markedly increased with the number of infections happening in China, where there are likely to be significant numbers of immune-suppressed individuals.
“It’s just increasing the probability that we’re going to see new variants emerging and spreading. So that's the concern really with what’s happening in China,” he said.
Prof Gupta, who was named one of the 100 Most influential people by TIME in 2020, concluded: “I believe that coronavirus or SARS-CoV-2 is here to stay. It may become one of the seasonal coronaviruses over time. It's difficult to tell, and whether we will need ongoing vaccination is also another thing that we need to address.
“It may become like influenza, where we do need yearly updates or updates every few years because the virus is changing so much that we don't want to become vulnerable to severe disease.”