The World Health Organization added XBB.1.16 to its list of variants under monitoring on March 22. The omicron subvariant has been reported in 22 countries, with most cases detected in India.
In India, XBB.1.16 has replaced the other variants that are in circulation, Maria Van Kerkhove, PhD, the WHO's technical lead for COVID-19, said during a March 29 update. India is seeing a significant jump in cases, reporting the highest single-day increase in nearly six months on April 2, CNBCT reported.
XBB.1.16 has a very similar profile to XBB.1.5 — the dominant strain in the U.S. — with one additional mutation in the spike protein that has shown increased infectivity and a potential increase in pathogenicity in lab studies, according to the WHO.
"This is one to watch," Dr. Van Kerkhove said. "We're monitoring it because it has potential changes that we need to keep a good eye out on."
The strain has appeared in the U.S., though it does not appear on the CDC's variant proportion tracker.
"We haven't seen a change in severity in individuals or in populations, but that's why we have these [monitoring] systems in place," Dr. Van Kerkhove said.