Delta AY.4.2’s new, even more infectious cousin might actually be good news

On Thursday, British scientists released the kind of news everyone was afraid of as we went into winter — a new, more infectious branch of the Delta variant seems to be spreading rapidly across Britain.

A study by Imperial College found that the Delta subvariate – known to virologists as AY.4.2 – accounted for about 12 per cent of thousands of samples collected in a recent British government survey, which is about 2.8 per cent higher compared to the figures from the last month. .

It has previously been suggested that AY.4.2 could be up to 15 percent more transmissible than the dominant Delta variant, making it the most infectious coronavirus strain since the onset of the pandemic.

However, the imperial scientists say they believe the spread of the variant may not be bad news for one crucial reason – it seems to cause significantly less symptomatic disease. Of the AY.4.2 samples collected in a government survey, only a third had the classic COVID symptoms, while half of patients with the original Delta experience those symptoms.

“It rather seems to be more transferable,” imperial epidemiologist Paul Elliott told reporters. “We don’t know why it’s more transferable. It seems to be less symptomatic, which is good. “

However, other experts said it is too early to say how the spread of AY.4.2 will change the course of the pandemic. Although fewer symptoms could mean that fewer people become seriously ill, it could also mean that infected people do their business without being tested.

Prof. Christl Donnelly, another of the Imperial researchers who worked on the report, said: “If it’s less likely to be symptomatic, then that means it’s being tested for less, and people may be out … On the other hand, if they don’t cough, it may spread less far. “

Simon Clarke, an associate professor of cell microbiology at the University of Reading, suggested that the seemingly lower rate of symptomatic disease could be distorted by demographics.

“What the data doesn’t tell you is where those infections are,” Clarke said. “So if they’re in younger people, or if they’re in a community that has a higher-than-average vaccine intake, that could cause issues.”

Whatever effect the new variant has, the research has clarified one thing: vaccines work, and acceleration shots become decisive. The study found that the risk of infection was about three times lower in people who received a third dose compared to those who received two. For more than fifty years, a third dose has reduced the risk of infection by about half.

Jenny Harries, chief executive of the British government’s Health Security Agency, said in a statement that the study “provides another reminder of the effectiveness of vaccines against COVID-19. As we approach winter, it is essential that all eligible come for their stings — whether that’s their first dose, second, or acceleration. “


Leave a Comment