Washington, Jun 19 (IANS): The Delta coronavirus variant is expected to become the dominant strain in America, Director of the US Centers for Disease Control and Prevention (CDC), Rochelle Walensky said.

The Delta variant, also known as B.1.617.2, is more transmissible than others, Xinhua news agency quoted Walensky as saying in an ABC News interview on Friday.

"As worrisome as this Delta strain is with regard to its hyper transmissibility, our vaccines work.

"Right now, they are working and they require actually two doses to be fully vaccinated, to work well.

"So I would encourage all Americans, get your first shot and when you're due for your second, get your second shot and you'll be protected against this Delta variant," she added in the interview.

The CDC has elevated the Delta strain from "variant of interest" to "variant of concern", which means the agency officially recognises that itmay carry a risk of more severe illness and transmissibility.

According to the CDC, the Delta variant accounts for up at least 10 per cent of all the confirmed coronavirus in the US.

On May 22, the variant had made up only 2.7 per cent of cases.

In addition to Delta, the CDC has noted five other variants of concern.

The US continues to be the worst-hit country with the world's highest number of cases and deaths at 33,519,262 and 601,281, respectively, according to the Johns Hopkins University.