First case of co-infection with 2 subvariants of Omicron reported in Bulgaria

A 76-year-old woman was infected simultaneously with both Omicron subvariants BA.5.1 and BA.2. The hybrid variant was named "XAN”, the National Centre for Infectious and Parasitic Diseases (NCIPD) said on October 5.

NCIPD detected "XAN” after it completed the sequencing of 94 samples taken from Covid-19 patients in the country,

They explain that when a person is infected simultaneously by two different viruses with similar genetic material, they multiply rapidly in human cells and may exchange some of their genetic make-up. This is how the hybrid subvariants, made up of the two parent viruses, are formed. "XAN" has spread little around the world and the woman infected in Bulgaria has recovered from the illness.

According to NCIPD, the incidence curve of COVID-19 in Bulgaria is again going up. To date, the country has an average of 131 infections per 100,000 population.