The new strain, XBB.1.5, was first detected on the east coast in late October and gained traction in December. Over the last four weeks, it has quickly edged out the previously dominant strains to make up 40 percent of cases nationally.⁠ ⁠ It appears to be more transmissible than its predecessors, based on early lab results, with properties that help it evade vaccine immunity, said Dr. Luis Ostrosky, chief of infectious diseases with UTHealth Houston and Memorial Hermann Hospital.⁠ ⁠ Ostrosky and other experts say the new strain is likely contributing to the rise in cases throughout Houston, where the percentage of positive tests jumped from 8.1 percent to 11.1 percent last week, according to the most recent data from the Texas Medical Center.⁠ ⁠ The average number of weekly COVID hospitalizations also saw a sharp uptick last week, from 529 to 663, including intensive care unit beds.⁠ ⁠ Click the link in our bio to read more.