AY.4.2 COVID Variant No More Vaccine-Resistant Than Original Delta, Report Finds

The AY.4.2 coronavirus variant does not appear to be any more vaccine-resistant than other Delta types, according to a new U.K. government report.

AY.4.2 is a sub-type of the Delta variant that has made headlines over the past few weeks due to its rise in the U.K., where it has accounted for up to 15 percent of new cases.

Research has found that AY.4.2 appears to have a small growth advantage over other circulating variants, though according to the U.K.'s risk assessment for the variant it's not yet entirely clear why.

The new report, a technical briefing from the U.K. Health Security Agency, also shows, based on the results of a study between June 21 and October 29, vaccine effectiveness against AY.4.2 "is very similar" to that seen in other types of Delta.

In fact, according to preliminary results from live virus neutralization studies mentioned in the report, Delta AY.4.2 might be even more easily neutralized by vaccines.

The report notes that AY.4.2 is still classed by the U.K. government as a variant under investigation, or VUI, as opposed to a variant of concern.

According to the COVID-19 variant tracking tool Outbreak.Info, which collects sequencing data from the viral genome database GISAID, there were a total of 37,249 cases of AY.4.2 worldwide as of November 12.

The vast majority of these cases, 35,225, were in the U.K.

The variant is not reported to be spreading anywhere near as fast anywhere else in the world, including in the U.S., where Outbreak.Info reports only 34 cases from 13 states.

On Friday, AY.4.2 was present in 38 countries around the world including the U.S. and U.K.

The variant is identified by two mutations in its spike genome—the part of the virus used to enter human cells. These mutations are called Y145H and A222V, and little is known about them, experts have previously told Newsweek.

U.S. officials do not appear to have been concerned by AY.4.2 recently. Rochelle Walensky, director of the Centers for Disease Control and Prevention (CDC), acknowledged that the variant had been identified in the country in a White House COVID-19 press briefing on October 20, adding that "there is no evidence that the sub-lineage AY.4.2 impacts the effectiveness of our current vaccines or therapeutics."

While the U.K. currently treats AY.4.2 as a separate variant to the rest of Delta, the CDC still lists all AY lineages under the same "Delta" umbrella.

AY.4.2 is only one sublineage of the Delta variant. There are dozens of descendants altogether.

COVID vaccine being given
A photo shows a COVID vaccine being administered at the John Knox Village Continuing Care Retirement Community in Florida on January 6, 2021. AY.4.2 does not appear to be more vaccine-resistant than other Delta types, according to a new report. Joe Raedle/Getty