New COVID-19 Variant ‘Delta Plus’ Is 15% More Contagious, Cases Recorded In Massachusetts

Delta Plus, the offshoot subvariant of the Delta COVID-19 variant, appears to be more contagious than the original strain, according to Israel’s Health Ministry.

The new COVID-19 subvariant, AY.4.2., is at least 15% more contagious than the original Delta variant. However, researchers have yet to find evidence that the Delta Plus subvariant is deadlier or more capable of evading vaccines than the original variant, according to the Times of Israel.

The original Delta variant itself was 60% more transmissible than the Alpha variant, according to a consensus statement published June 2, 2021. The Alpha variant was 50% more contagious than the original COVID-19 strain that spread from China.

The Delta Plus variant was first detected in the United Kingdom where it now accounts for 6% of all COVID-19 infections reported. It has since been recorded in at least five states in the U.S., including Massachusetts where the offshoot variant was detected in six of the 53,884 COVID-19 samples sequenced as of Monday, according to outbreak.info.

The Delta Plus subvariant has also been detected in sequenced samples from California, Washington D.C., Washington state and North Carolina.

U.S. health officials are now “very carefully” monitoring the new subvariant, which is currently classified as a “variant under investigation.”

“We’re watching it very carefully. We have had a handful of cases here in the United States but it has not taken off as it has in the UK,” Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention, said on NBC’s Meet the Press.

“It has several mutations on the spike protein that we have not yet seen implicated in increased transmissibility or in a decreased ability of our vaccines or therapeutics to work.”

Justin Lessler, an epidemiologist at the University of North Carolina, said he believes the new Delta Plus subvariant is unlikely to reverse the decline in infections in the U.S. He noted that only a variant that evades the antibodies in vaccines could bring about a resurgence of infections.

"Even with a variant that's way more transmissible than delta-plus, cases didn't go back to the types of peaks we saw last winter or even the types of peaks we've seen in the delta wave," Lessler told NPR.