A newly emerging coronavirus variant with signs of immune escape has been detected in California wastewater, offering an early signal that the virus continues to evolve even as COVID-19 activity remains low across the state.
The variant, known as BA.3.2, has also been found in a small number of patients and international travelers in the United States, according to a March 19 report from the Centers for Disease Control and Prevention.
The finding is also notable because it puts fresh federal attention on COVID at a time when the virus has largely faded from public view and from much of Washington’s public health messaging.
Its first documented U.S. detection came through a traveler at San Francisco International Airport last June.
What is drawing attention is how genetically distinct this version of the virus looks.
BA.3.2 carries roughly 70 to 75 mutations in its spike protein compared with recent strains, the CDC said. Some of those changes may help it partially evade immunity from past infections or vaccination, though scientists say it’s still too early to know what that means in real-world terms.
So far, however, there is no sign the variant is driving a surge. It accounted for 0.55% of sequenced U.S. cases as of mid-March and has not overtaken the variants currently circulating. In California, COVID-19 activity “remains very low statewide,” according to the California Department of Public Health.
There is no indication that BA.3.2 causes a different kind of illness. Like other recent variants, it appears to cause mostly mild, cold-like symptoms, making it difficult to distinguish from other respiratory infections.
Still, the way BA.3.2 is being detected, first in wastewater, fits a pattern that has defined the pandemic in recent years. New variants often show up in sewage data weeks before they are widely identified in patients.
UCSF infectious disease specialist Dr. Peter Chin-Hong said the bigger risk may not be the variant itself, but how people respond to it.
“COVID-19 may feel like it is fading into the rearview mirror, but the virus has not returned the favor,” he said. “Complacency, not just mutation, is now one of our greatest risks.”