New Covid variant BA.3.2 detected across US, but experts urge vigilance over alarm | US news

BA.3.2, an Omicron variant of Covid-19 with dozens of new spike mutations, has been detected in 29 U.S. states and Puerto Rico, according to the Centers for Disease Control and Prevention, but experts say there is no evidence yet that it is more serious than other recent variants.

“The right response to BA.3.2 is serious attention, not alarm,” says Dr. Jake Scott, a Stanford professor and infectious disease expert who wrote a systematic review of Covid vaccines for the New England Journal of Medicine.

“This is a striking variant, with substantial changes in its spike protein, and it makes sense that the World Health Organization’s Vaccine Composition Panel has already flagged it for discussion at its May meeting,” Scott said, adding that the WHO has classified BA.3.2 as a “variant under surveillance,” while refusing higher-risk designations so far. In addition to vaccines, WHO recommends masking and improved ventilation in high-risk environments – to prevent all Covid-19 infections and associated risks, such as long Covid.

Scott said that, according to the WHO, “BA.3.2 has not shown a sustained growth advantage over any other co-circulating variant, and there is no data indicating increased severity, hospitalizations or deaths associated with this variant.” In the United States, BA.3.2 still represents a small percentage of overall Covid-19 infections that have been analyzed, according to the CDC, but Scott said that “in parts of Europe, it has reached a substantial share of sequenced cases without clear signs of worse clinical outcomes.”

Marc Veldhoen, an immunologist at the University of Lisbon, agreed that in many ways BA.3.2 was just a typical subvariant of Omicron: “This means that biologically no major differences have been reported or are expected: this is Omicron Sars-CoV-2. » Symptoms are similar to other respiratory infections. While some media outlets have referred to BA.3.2 as a “highly” or “highly” mutated variant, Veldhoen said “highly mutated is relative; Sars-CoV-2 is nearly 30,000 base pairs long.”

Current vaccines appear to work as expected against the new variant, according to Veldhoen and Scott, although it’s possible the mutation will play a role in how next year’s vaccine is updated.

“The question that really matters is whether BA.3.2 significantly erodes protection against severe disease,” said Scott, who added that at present all the evidence shows that this is not the case.

While Scott admitted that “antibodies that target the Spike protein may lose some effectiveness when the virus changes significantly,” he noted that “vaccines and previous infections also build a deeper layer of immune memory, which goes beyond antibodies and can recognize and fight the virus even after it has mutated.” This protection has been durable despite the variants, he said, “and this is one of the main reasons why protection against hospitalization and death has remained more resilient than protection against infection.”

For now, public health officials, the general public and doctors do not need to change their behavior in the face of this variant, Veldhoen said. Vaccine researchers, meanwhile, should continue to monitor the variant to determine how best to update the vaccine, Veldhoen added.

Scott acknowledged another concern raised by some researchers about BA.3.2. In the Global Initiative for Influenza Data Sharing (Gisaid) database, which includes all available Covid-19 sequencing data, BA.3.2 is “over-represented in pediatric samples compared to adults in several countries, and this trend appears real.”

But Scott said he “would be cautious about moving from ‘more commonly sequenced in children’ to ‘preferentially infects children’ in a clinically meaningful sense.”

Scott noted: “Sequencing data reflects who is tested and whose samples are sequenced, not who is actually infected. »

While adults with mild infections are less likely to get tested and have their results sequenced these days, children with symptoms are more likely to be tested and seen in clinical settings where their virus will actually be sequenced. Another possibility noted by Scott and Veldhoen is that children are more likely to be infected simply because they have less accumulated exposure than adults to different Covid-19 variants over the years.

“More importantly, there are currently no signs that BA.3.2 causes more severe illness in children,” Scott said, adding that until there is, the trend is noteworthy but not catastrophic.

“The goal was never to prevent every infection. It was to keep people out of the hospital. This protection has proven to be stronger than variant-by-variant headlines often suggest.”