On Monday, Dr Maria Van Kerkhove, COVID-19 technical lead at the World Health Organization, had said that the B.1.617 virus variant that was first identified in India had been classified as a "variant of interest".
The U.S. Centers for Disease Control and Prevention (CDC) is "closely monitoring" a coronavirus variant first identified in India, a spokesperson told Fox News.
The WHO noted that the India variant appears to be highly transmissible, as several countries have reported rapid surges in infections.
The B.1.617 variant is the fourth variant to be designated as being of global concern and requiring heightened tracking and analysis.
As per the United Nations health agency, the B.1.617 variant of coronavirus, which was first identified in India in October, has been detected in more than 4,500 samples from "44 countries in all six WHO regions" through an open-access database. "So, guessing there is some reduced neutralisation, as such, we are classifying this a variant of concern at the global level".
The World Health Organisation has said a recent risk assessment of the situation in India found that "resurgence and acceleration" of COVID-19 transmission in the country had several potential contributing factors, including "several religious and political mass gathering events which increased social mixing".
American health officials dubbed B.1.617 a "variant of interest" last week, due to its worrisome mutations.
The others are those first detected in Britain, South Africa and Brazil.
The variants are seen as more risky than the original version of the virus because they are either being more transmissible, deadly, or able to get past some vaccine protections.
The WHO insisted though that it was far too early to interpret this to mean that the variant might have more resistance to vaccine protections.
'Even though there is increased transmissibility demonstrated by some preliminary studies, we need much more information about this virus variant and this lineage and all of the sub-lineages, ' she said.
Preliminary analyses conducted by the World Health Organization, using sequences submitted by India to a global database, suggest that B.1.617.1 and B.1.617.2 have a substantially higher growth rate than other circulating variants in India. The shift suggests that B.1.617 has a higher growth rate than other variants circulating in India, with the possible exception of B.1.1.7.
Viruses in the B.1.617 lineage were first reported in India in October 2020.
While B.1.1.7 and B.1.612.1 variants have begun to wane in recent weeks, a marked increase in the proportion of viruses sequenced as B.1.612.2 has been observed over the same period, it said.
And Van Kerkhove stressed that when it comes to the B.1.617 variant, for the time being "we don't have anything to suggest that our diagnostics or therapeutics and our vaccines don't work". Since the identification of these variants through late April 2021, B.1.617.1 and B.1.617.2 accounted for 21% and 7% of sequenced samples from India, respectively, the apex global public health agency said.