National Center of Infectious and Parasitic Diseases, Sofia, Bulgaria

Communication on the spread of SARS-CoV-2 variants in the country December 17, 2024

The NCIPD has successfully analyzed 55 clinical samples with SARS-CoV-2 by next-generation whole genome sequencing. The samples were collected from patients with COVID-19 from 5 regions of the country in the period 27.09-30.10.2024, and were sent by 5 laboratories.

Omicron and its subvariants were detected in all samples. ХЕC 3 (5.5%) of the proven SARS-CoV-2 variants were defined by WHO as Variants Under Monitoring (VUM) (as of 29 November 2024).

KP.3 was detected in one sample (2%), which was designated by WHO as of variant of interest (VOI). Other KP(FLiRT) subvariants were also detected (33/60.1%) in addition to the detected subvariants: JN.x (1/2%), LB.x (3/5.5%), MC.x (7/12.7%), and (7/12.7%) other subvariants of SARS-CoV-2 were detected.

Nextclade v3.8.2 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.