During the second week of 2026(5.01.-11.01.2026), 4,633 cases of acute respiratory diseases and influenza were registered among a monitored population of 347,913 people, representing an incidence rate of 133.17 per 10,000 population. During the previous week, 2,301 cases of acute respiratory diseases and influenza were registered among a monitored population of 347,913 people, representing an incidence rate of 66.14 per 10,000 population. The incidence rate for the country and by age group has increased compared to the previous week. This is particularly evident in the 0-4 age group (470.48 per 10,000 population) and in the 5-14 age group (340.16 per 10,000 population). The incidence rate in the Varna region (239.38%oo), where a flu epidemic has been declared, is at epidemic levels. High levels of acute respiratory infections, including flu, have been recorded in the regions of Silistra (213.5%oo), Dobrich (207.0%oo), Pernik (196.1%oo), Burgas (186.9%oo), Sofia region (185.4%oo), Smolyan (159.3%oo), and Veliko Tarnovo (120.5%oo).

During week 2, 236 clinical samples from patients with ARI were tested by Real Time PCR at the National Reference Laboratory for Influenza and ARI. Sixty-five cases of influenza A(H3N2) virus and seven cases of influenza A/H1N1 (2009) virus were confirmed.
In children under 5 years of age, the following were confirmed in the 186 clinical samples tested: influenza virus A/H3N2 (54), influenza virus A/H1N1 (2009) (6), AdV (3), RSV (5), PIV (2), and other viruses (18).