URGENT: OMICRON BA.2.75 sub-variant may be a problem, pre-print study in hamsters suggest BA.2.75 is more infectious & harmful than even dominant BA.5 & BA.2; BA.2.75 caused focal viral pneumonia...
by Paul Alexander
in hamsters, characterized by patchy inflammation interspersed in alveolar regions, not observed in BA.5-infected hamsters. BA.2.75 replicated better than BA.5 in the lungs of hamsters.
‘The prevalence of the Omicron subvariant BA.2.75 is rapidly increasing in India and Nepal. In addition, BA.2.75 has been detected in at least 34 other countries and is spreading globally. However, the virological features of BA.2.75 are largely unknown. Here, we evaluated the replicative ability and pathogenicity of BA.2.75 clinical isolates in Syrian hamsters. Although we found no substantial differences in weight change among hamsters infected with BA.2, BA.5, or BA.2.75, the replicative ability of BA.2.75 in the lungs was higher than that of BA.2 and BA.5. Of note, BA.2.75 caused focal viral pneumonia in hamsters, characterized by patchy inflammation interspersed in alveolar regions, which was not observed in BA.5-infected hamsters. Moreover, in competition assays, BA.2.75 replicated better than BA.5 in the lungs of hamsters. These results suggest that BA.2.75 can cause more severe respiratory disease than BA.5 and BA.2 and should be closely monitored.’