Another mutation of the COVID-19 virus has been detected in at least eight states plus Washington, D.C. as of Tuesday, but officials have not yet indicated concern about a potential spike in cases due to the variant.
Formally known as AY.4.2, the strain is a “sub-lineage” of the highly transmissible delta variant of SARS-CoV-2, the strain that makes up the vast majority of cases in the United States. Subvariant AY.4.2 was detected in the U.K in September; a report issued by U.K. officials in late October said the variant made up 6% of all analyzed COVID-19 cases in the country and is “on an increasing trajectory.”
Since the AY.4.2 variant was first identified, Washington, D.C., Rhode Island, Nevada, Maryland, North Carolina, Massachusetts, Washington and Florida have each reported one COVID-19 case from the AY.4.2 lineage, while California has identified AY.4.2 in two of its sequenced COVID-19 cases.
White House officials in late October said they had not yet seen “recent increased frequency or clustering” of the AY.4.2 variant, which is also sometimes referred to as "delta-plus".
“Over the past nine months, as we have previously reported, we have ramped up our sequencing capabilities in partnership with local public health and academic institutions,” Dr. Rochelle Walensky, director of the U.S. Centers for Disease Control and Prevention, said at a White House briefing on Oct. 20. “We particularly monitor for sub-lineages that could impact therapeutics, such as monoclonal antibodies and vaccines.”
“At this time, there is no evidence that the sub-lineage AY.4.2 impacts the effectiveness of our current vaccines or therapeutics,” she added.
The AY.4.2 sub-variant has two mutations in the spike protein, which helps the coronavirus invade the body’s cells. These changes have also been seen in other versions of the virus since the pandemic started, but experts say such variants have yet to significantly contribute to the global spread of the disease.
The delta variant remains “by far the most dominant variant in terms of global circulation” said Maria Van Kerkhove, the World Health Organization’s technical lead on COVID-19, at a public session this week.
“Delta is dominant, but delta is evolving,” she said, adding that the more the virus circulates, the greater chances it has to mutate.
The U.N. health agency is currently tracking 20 variations of the delta variant. The AY.4.2 is “one to watch because we have to continuously keep an eye on how this virus is changing,” said Van Kerkhove.
Less than 27,000 cases of the AY.4.2 lineage have been identified worldwide, representing a cumulative prevalence of 1% of the globe’s overall cases since May 2021. Cases of AY.4.2 are currently most prevalent in Europe.
Spectrum News has reached out to the CDC for comment.
The Associated Press contributed to this report.