National Center of Infectious and Parasitic Diseases, Sofia, Bulgaria

Communication on the spread of SARS-CoV-2 variants in the country February 5, 2024

The NCIPD has successfully analyzed 74 clinical samples with SARS-CoV-2 by next-generation whole genome sequencing. The samples were collected from patients with COVID-19 from 9 regions of the country in the period 24.11.2023-11.01.2024 and were sent by 8 laboratories.

Omicron and its subvariants were detected in all samples. ХВВ.1.9.1 was detected in one of the samples (1.3%), designated by the WHO as a variant under monitoring (VUMs).The distribution of proven variants defined by WHO as variants of interest (VOIs) was: 28 (37,8%) BA.2.86, 1(1.3%) ЕG.5, 1(1.3%) XBB.1.5, and 1(1.3%) XBB.1.16. In addition, subvariants were BA.x 50(67,6%), ХBB.х 13 (17,6%), FL.x 4(5.4%), and 7(9,4%%) other subvariants.

Pangolin COVID-19 Lineage Assigner v4.3. 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 which are of increased public health importance.