The National Center for Infectious and Parasitic Diseases (NCIPD) reports that 165 clinical samples with SARS-CoV-2 collected from 01 June – 06 July 2022 were analyzed by next-generation whole-genome sequencing. The clinical samples were collected in 14 different medical centers, from 16 districts of the country.

For the first time in Bulgaria, subvariants BA.4 were identified in Sofia (capital) and Burgas region.

In all 165 clinical samples, the Omicron variant was identified. The Omicron subvariant ratio is as follows: BA.2.x (41%), BA.4.x (1.8%), BA.5.x (41.2%), BE.1.x (9.7%) and BF.1.x (5.5%).

The number of the faster-spreading variant BA.5.x is increasing, respectively 37.7% in June and 68.4% in July. The highest prevalence of variant BA.5.x is observed in the regions of Burgas and Varna (66.7%), followed by the district of Sofia and Sofia (capital) (38.6%) and all other regions (34.9%).

Pangolin COVID-19 Lineage Assigner v4.1.1. program was used to define SARS-CoV-2 variants. An epidemiological analysis is being carried out.

For information on the classification of SARS-CoV-2 variants and sub-variants, please visit: https://cov-lineages.org/index.html

For an up-to-date classification of the variants of concern (VOC), please visit:

https://www.ecdc.europa.eu/en/covid-19/variants-concern

https://www.who.int/en/activities/tracking-SARS-CoV-2-variants/

The NCIPD continues to monitor the spread of SARS-CoV-2 in the country, with a focus on VOC, altered virulence and immunogenicity that are of increased public health importance.