A new version of the Delta coronavirus variant has been reported in a number of countries including the United Kingdom, United States, and India, health officials say.

This strain is called B.1.617.2.1 or AY.1 — Delta Plus for short and is a version of the Delta variant first detected in India in February.

The variant, called “Delta Plus” in India, was first reported in a Public Health England bulletin on June 11.

The Indian government said it has submitted the variant to the Global Data System and sent samples for genomic testing.

Public Health England, noted in its last summary that routine scanning of Covid-19 cases in the country has found almost 40 cases of the newer variant, which has acquired the spike protein mutation K417N, i.e. delta plus.

Health experts are investigating whether Delta Plus may be more transmissible than other strains, like the Alpha or Delta variants. About 200 cases have been spotted in 11 countries.

“The mutation K417N has been of interest as it is present in the Beta variant (B.1.351 lineage), which was reported to have immune evasion property,” India’s health ministry said in a statement.

These countries include Britain (36), Canada (1), India (8), Japan (15), Nepal (3), Poland (9), Portugal (22), Russia (1), Switzerland (18), Turkey (1), the United States (83).

On Wednesday, India said around 40 cases of the variant have been observed in the states of Maharashtra, Kerala, and Madhya Pradesh, with “no significant increase in prevalence”.

The earliest case in India is from a sample taken on April 5.

Britain said its first 5 cases were sequenced on April 26, and they were contacts of individuals who had travelled from, or transited through, Nepal and Turkey. Currently, no deaths were reported among the UK and Indian cases.

According to Shahid Jameel, a top Indian virologist, K417N was known to reduce the effectiveness of a cocktail of therapeutic monoclonal antibodies.

Globally, studies are ongoing to test the effectiveness of vaccines against the mutation.

“WHO is tracking this variant as part of the Delta variant, as we are doing for other Variants of Concern with additional mutations,” the World Health Organization (WHO) said in a statement sent to Reuters.

The statement was further quoted saying, “For the moment, this variant does not seem to be common, currently accounting for only a small fraction of the Delta sequences…Delta and other circulating Variants of Concern remain a higher public health risk, as they have demonstrated increases in transmission.”