The Omicron subvariant BA.3.2, characterized by numerous spike protein mutations, has been identified across 29 states in the U.S. and Puerto Rico, as reported by the Centers for Disease Control and Prevention. However, health experts currently affirm that there is no substantial evidence suggesting this variant is more severe than its predecessors.

“BA.3.2 warrants careful attention but not alarm,” advises Dr. Jake Scott, an infectious disease expert at Stanford University and the author of a systematic review on COVID-19 vaccines for the New England Journal of Medicine.

Dr. Scott highlights the significant alterations in the spike protein of BA.3.2, noting the World Health Organization (WHO) has already prioritized it for discussion at their upcoming meeting in May. Although classified as a “variant under monitoring” by WHO, it hasn’t been elevated to a higher risk category. WHO continues to recommend vaccinations, mask-wearing, and enhanced ventilation in high-risk settings to curb COVID-19 infections and mitigate risks like long COVID.

Dr. Scott also pointed out that, according to WHO, BA.3.2 hasn’t demonstrated a consistent growth advantage over other variants in circulation, nor is there evidence of increased severity, hospitalizations, or fatalities linked to it. While the CDC indicates that BA.3.2 represents a minor fraction of analyzed COVID-19 cases in the U.S., Dr. Scott notes that it has become a notable presence in parts of Europe without leading to worsened clinical outcomes.

Marc Veldhoen, an immunologist at the University of Lisbon, concurs that BA.3.2 resembles a typical Omicron subvariant. “Biologically, there are no significant differences reported or anticipated. It is essentially Omicron SARS-CoV-2,” he explains. Symptoms mirror those of other respiratory infections. Despite media portrayals of BA.3.2 as “highly” mutated, Veldhoen clarifies, “Heavily mutated is relative; SARS-CoV-2 comprises nearly 30,000 base pairs.”

Both Veldhoen and Dr. Scott indicate that current vaccines remain effective against BA.3.2, though the mutation could influence updates to next year’s vaccine formulations.

“The question that actually matters is whether BA.3.2 meaningfully erodes protection against severe disease,” said Scott, who added that as of now, all evidence shows that it doesn’t.

While Scott admitted that “antibodies that target the spike protein can lose some effectiveness when the virus changes significantly,” he noted that “vaccines and prior infection also build a deeper layer of immune memory, one that goes beyond antibodies and can recognize and fight the virus even after it has mutated.” That protection has been durable across variants, he said, “and it’s a major reason protection against hospitalization and death has remained more resilient than protection against infection”.

For the moment, public health officials, the general public and doctors do not need to change their behavior in response to this variant, Veldhoen said. Vaccine researchers, on the other hand, should be continuing to track the variant in order to determine how to best update the vaccine, Veldhoen added.

Scott acknowledged another concern some researchers have raised about BA.3.2. In the Global Initiative on Sharing All Influenza Data (Gisaid) database, which includes all reported sequencing data available on Covid-19, BA.3.2 is “overrepresented in pediatric samples relative to adults in several countries, and that pattern appears real”.

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

Scott noted: “Sequencing data reflects who gets tested and whose samples get sequenced, not who actually gets 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 that both Scott and Veldhoen noted 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 is no current signal that BA.3.2 is causing more severe disease in children,” Scott said, adding that until there was, the pattern was worth noting but not catastrophizing.

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