Despite the fact that they’re driving a spurt in COVID cases, the World Health Organization (WHO) says XBB and BQ.1 are not different enough from each other, or from other Omicron lineages, to warrant labelling them new variants of concern. Variants of concern are those that show increased transmissibility, virulence or change in clinical disease, and a decreased effectiveness of public health and social measures. XBB and BQ.1 are subvariants of Omicron, which continues to be a variant of concern. Examining global data available to date, WHO said there is early evidence that there is a higher risk of COVID-19 reinfection from XBB and BQ.1 compared to other circulating Omicron subvariants. However, cases of reinfection appear to be largely occurring in those previously infected with pre-Omicron strains, such as Delta, WHO says.