pune omicrons xbb15 which has been triggering covid spikes in parts of the us is comparable to other xbb subvariants in severity but is less virulent than the delta and ba275 variants of sarscov2 a study from pune has foundexperts from bj medical college the national institute of virology and the indian institute of science education and research teamed up to analyse seven xbb15 patients from maharashtra six from mumbai and one from pune and found that covid in them was mild all of them recovered at home after minimal treatment however the experts said xbb15 seemed as effective as ba275 in entering human cells it showed a stronger binding affinity to human ace2 receptors than other xbb offshoots thereby explaining its significant growth advantage over other xbbs it was similar to the binding ability that was displayed by ba275 said dr rajesh karyakarte maharashtras coordinator for genome sequencing and a senior scientist with bj medical college binding to the ace2 receptor is the critical early step before sarscov2 enters human cells dr karyakarte said the data from the study perhaps the first indian investigation of xbb15s abilities suggests the subvariant may have a low mortality rate just like other xbb versionsthe team had earlier studied various xbb sublineages but could not study xbb15 due to the lack of cases in maharashtra at the time the seven patients were only recent detections by the state health departmentsix of the seven patients had full medical histories the seventh person was unavailable for more followupsthe most common symptoms in the group were a cold and rhinorrhoea runny nose followed by sore throat fever and cough however none of them went on to need hospital admission or supplemental oxygen three of the six with medical histories had contracted covid in the past and four had also taken the booster dose of a vaccine out of the six cases four had history of travel to the us and germany one had travelled to gujarat and another had come in contact with a case with travel history to the us no deaths were reported among the detected xbb15 cases dr karyakarte said according to reports xbb15 is now in at least 60 of all covid cases in the us on january 21 the subvariant accounted for 495 of cases there indicating fast growthas of saturday january 28 india has recorded 33 xbb15 patients according to disease data released by indias surveillance network insacog