New Delhi, Apr 22 (IANS): The World Health Organization (WHO) has upgraded Omicron subvariant XBB.1.16 to a Covid-19 "variant of interest" (VOI) due to its "sustained increase" and "growth advantage" reported from several countries.

XBB.1.16 is a descendent lineage of XBB, a recombinant of two BA.2 descendent lineages. XBB.1.16 was first reported on January 9, this year and designated a variant under monitoring (VUM) on March 22.

So far, 3,648 sequences of the Omicron XBB.1.16 variant have been reported from 33 countries, including India, on open research platform GISAID, the global health body, said.

"Following a sustained increase in the prevalence of XBB.1.16 and growth advantage reported from several countries, WHO classifies XBB.1.16 as a VOI," said Maria Van Kerkhove, technical lead for Covid-19 response at WHO on Friday.

Van Kerkhove noted that XBB.1.16 has shown "growth advantage and immune escape".

While "no changes in severity have been reported, it can cause full range of disease", she said, adding for the need to "be vigilant".

Driven by XBB.1.16, India on Saturday recorded 12,193 fresh COVID-19 cases in a span of 24 hours, with the number of active cases of the infection going up to 67,556, according to the Union health ministry.

The WHO noted that although there has been a "slight increase" in XBB.1.16-related hospitalisation in India and Indonesia, the levels are "much lower than seen in previous variant waves".

Further, "available information does not suggest that XBB.1.16 has additional public health risk relative to XBB.1.5 and the other currently circulating Omicron descendent lineages,a the WHO said.

"However, XBB.1.16 may become dominant in some countries and cause a rise in case incidence due to its growth advantage and immune escape characteristics," it added.

Meanwhile, some experts nicknamed XBB.1.16 as Arcturus, after the brightest star in the northern celestial hemisphere. However, the WHO has not named it yet. WHO assigns Greek labels only for variants of concern (VOC), and not for VOIs.

"We are not using nicknames for these sub variants, and I would kindly encourage you not to. Please," Van Kerkhove said.