What is the delta plus variant?

Public interest in the delta plus variant is growing, but little information is available on the strain, a mutation of the widespread delta variant.

While cases of the delta plus have been seen for months in India, the U.K. and the United States, experts said the overall number of cases associated with this strain is relatively low.

“It’s been in the U.S., not that much, mostly India, probably southeast Asian and the U.K.,” said Dr. Ulysses Wu, Hartford HealthCare’s chief epidemiologist.

What separates delta plus from delta is a mutation of the spike protein, which is why it is given the “plus” designation, according to Wu.

“They don’t really know that much about it. They seem to be worried that it’s more transmissible, but I’ve read other reports that it’s the exact opposite,” Wu said.

Delta plus has not been designated on its own as a variant of concern, but rather is included in the general designation for delta, according to the Centers for Disease Control and Prevention’s website.

And exact numbers of infections connected with delta plus are not clear because most researchers and the CDC include delta plus infections toward total delta variant infections.

Nathan Grubaugh, whose team at Yale has been sequencing coronavirus samples, said in a Tweet last month that there have been Connecticut cases of the delta plus variant, also known as AY.1. A report he publishes weekly on the variants counts those cases toward the total number for the delta variant.

As of last week, the delta variant remained the dominant strain in Connecticut, mirroring a trend seen across the country. Officials are attributing an increase in COVID-19 cases to this strain.

Wu said research into the delta plus variant is ongoing. Though little is known about whether it has the characteristics that raise alarms, like it being more transmissible or have an ability to evade the vaccine, Wu said he is not yet concerned about delta plus.

“The reason I’m not so worried just yet … if it was that much of a concern, it should’ve overtaken this delta already,” Wu said.