The latest CDC estimates indicate omicron subvariant XBB.1.16 accounts for nearly 10 percent of COVID-19 cases in the U.S.
That's up from about 7 percent of cases when the agency first started tracking the subvariant April 14. Prior to that, the CDC hadn't been tracking the strain individually, since it was estimated to account for less than 1 percent of cases. The omicron relative is most prevalent in HHS region 6, where it makes up 14.4 percent of cases. That region includes Texas, Oklahoma, New Mexico, Louisiana and Arkansas.
Four more things to know as XBB.1.16 gains traction:
1. The variant is driving a surge in India, which saw an eight-month high in the number of new daily cases reported April 20, according to India Today. In an April 21 tweet, Eric Topol, MD, founder and director of Scripps Research Translational Institute in San Diego, said the strain is "unlikely to have such an impact" here in the U.S.
2. XBB.1.16 appears to cause a new symptom among children: conjunctivitis that presents without pus, but as "sticky eyes." Among a preprint study of 25 children in India who tested positive between April 4-16, nearly 43 percent had conjunctival involvement, according to Vipin Vashishtha, MD, a pediatrician in India and head of the Indian Academy of Pediatrics Committee on Immunization, who authored the study. The study also found the duration of illness appears to be between one and three days and that the strain is causing a "mild febrile illness," Dr. Vashishtha wrote in a Twitter thread about the findings. Of the children involved in the study, none required hospitalization.
3. The World Health Organization elevated XBB.1.16 from a variant under monitoring to a variant of interest its weekly COVID-19 report published April 20. "Due to it sestimated growth advantage and immune escape characteristics, XBB.1.16 may spread globally and contribute to an increase in case incidence. However, at present, there is no early signal of an increase in severity," the WHO's report said. An initial risk assessment on the strain is expected to be published in the coming days.
4. As the prevalence of XBB.1.16 grows, experts have said they don't anticipate the accuracy of at-home tests to be affected, since it has a very similar profile to XBB.1.5, with a mutation in the spike protein. Most at-home tests are designed to recognize the virus's nucleocapsid protein, not the spike protein.