National Center of Infectious and Parasitic Diseases, Sofia, Bulgaria

Communication on the spread of SARS-CoV-2 variants in the country November 5, 2025

The NCIPD has successfully analyzed 70 clinical samples with SARS-CoV-2 using next-generation sequencing. The samples were collected from patients with COVID-19 in five regions of the country between September 9, 2025, and October 17, 2025, and sent by five laboratories.

Omicron and its subvariants were detected in all samples tested. SARS-CoV-2 variants defined by WHO as Variants Under Monitoring (VUM) (as of October 31, 2025) were detected in 3 patient samples, NB.1.8.1 in 1 (1.4%) samples and XFG in 2 (2.9%) samples, respectively. In addition, XFG subvariants (XFGx 60/85.7%) as well as (7/10%) other SARS-CoV-2 subvariants were detected.

The Nextclade v3.8.2 program was used to define SARS-CoV-2 variants. An epidemiological analysis is underway.

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 (VOIs), please visit:

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

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