SARS-CoV-2 Delta AY.1 variant Cluster in an accommodation facility for COVID-19

Abstract

This is a case report on a cluster infection of novel severe acute respiratory syndrome coronavirus 2 delta AY.1 variant at an accommodation facility and the subsequent attempts to isolate individuals who tested positive. The background that facilitated this cluster was investigated, and the conditions in which infection was established, the infection route, and the effectiveness of routine measures were evaluated. Ninety-nine staff members had been working at the accommodation facility at the time of infection, and it was estimated that 10 members were infected with the delta AY.1 variant. Our results suggest that infection of staff from a patient staying overnight should be excluded. The factors contributing to the cluster infection involved short-distance conversations with individuals wearing non-woven three-layer masks moved out of position (non-woven) and gathering together with individuals wearing non-woven masks in hypoventilated conditions. Our findings also indicate that this variant is possibly airborne and can infect individuals in enclosed spaces with poor ventilation, even when either infected or exposed individuals wear non-woven masks. The routine maintenance of systems established for the detection of infections and prompt and appropriate preventive measures following the identification of positive individuals will help prevent further cluster infections.