New Covid variant BA.3.2 detected across US, but experts urge vigilance over alarm | US news
BA.3.2, an Omicron variable Dozens of new spike mutation Covid-19 cases were detected in 29 states of the USA and Puerto Rico. According to the Centers for Disease Control and PreventionBut experts say there is no evidence yet that it is more severe than other new variants.
Stanford professor and infectious diseases expert Dr. “The proper response to BA.3.2 is not to raise alarm, but to pay serious attention,” says Jake Scott. Wrote a systematic review of Covid vaccines For the New England Journal of Medicine.
“This is a striking variant with significant changes in the spike protein, and it makes sense that the World Health Organization’s vaccine composition group has already flagged this for discussion at its meeting in May,” Scott said, adding that the WHO has classified BA.3.2 as a “variant under surveillance” but has so far rejected higher risk designations. Besides 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: According to WHO“BA.3.2 has not demonstrated a sustained growth advantage over other co-circulating variants, and there are no data to suggest an increase in severity, hospitalizations, or deaths associated with this variant.” In the US, BA.3.2 still accounts for a low percentage of overall Covid-19 infections analyzed. According to HKMbut Scott said: “In some parts of Europe it has risen to a significant share of consecutive cases without a clear signal of worse clinical outcomes.”
Immunologist Marc Veldhoen from the University of Lisbon agrees that BA.3.2 is in many respects a typical subvariant of Omicron: “This means that no major differences have been reported or expected biologically: Omicron Sars-CoV-2.” Symptoms are similar to other respiratory infections. While some media outlets have called BA.3.2 a “highly” or “severely” mutated variant, Veldhoen said “severe mutation is relative; Sars-CoV-2 is about 30,000 base pairs long.”
Current vaccines appear to work as intended against the new variant, according to Veldhoen and Scott, but it’s possible the mutation could play a role in how next year’s vaccine is updated.
“The really important question is whether BA.3.2 meaningfully erodes protection against serious disease,” Scott said, adding that all evidence as of now suggests this is not the case.
While Scott acknowledged that “antibodies targeting the spike protein may lose some effectiveness when the virus changes significantly,” he noted that “vaccines and previous infections also create a deeper layer of immune memory that goes beyond antibodies and can recognize and fight the virus even after it has mutated.” This protection is durable across variants, he said, “which is an important reason why protection against hospitalization and death remains more resilient than protection against infection.”
For now, public health officials, the general public and doctors do not need to change their behavior in response to this variant, Veldhoen said. Veldhoen added that vaccine researchers should continue to monitor the variant to determine how best to update the vaccine.
Scott also acknowledged another concern some researchers have raised about BA.3.2. In the Global Initiative on Sharing of All Influenza Data (Gisaid) database, which contains all reported sequencing data on Covid-19, BA.3.2 is “overrepresented in pediatric samples relative to adults in several countries, and this pattern appears to be real.”
But Scott said he would be “cautious about moving from ‘more common in children’ to ‘preferably infects children’ in a clinically meaningful sense.”
“Sequencing data reflects who was tested and whose samples were sequenced, not who was actually infected,” Scott noted.
While adults with mild infections are less likely to be 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, both Scott and Veldhoen noted, is that children are more likely to become infected because they have been less exposed to different Covid-19 variants over the years than adults.
“Importantly, there is no current signal that BA.3.2 causes more severe disease in children,” Scott said, adding that until it does, the pattern is notable but not catastrophic.
“The goal was never to prevent every infection. The goal was to keep people out of the hospital. This protection has proven to be stronger than the variants often highlighted in the headlines.”
