Key points

Bronchiolitis

• Epidemic slowly declining.

• Bronchiolitis-related activity remains at a post-epidemic level in Week 4: 8.8% (vs. 8.6% in Week 3) of emergency department visits; 4.8% (vs. 2.3%) of SOS Médecins calls. Activity is lower than in the previous two winters.

• The rate of bronchiolitis hospitalizations among all coded hospitalizations increased this week (24% vs. 20% in S-1).

• Circulation of RSV has stabilized in private laboratories (7.7% in Week 4 vs. 7.4% in Week 1) and is trending downward in hospitals (5.1% in Week 4 vs. 6.7% in Week 1).

Influenza

• Rebound in the 8th week of the epidemic.

• Influenza-related activity (all ages) is rising again among emergency department visits in Week 4, with 6.6% of cases attributed to influenza (vs. 5.2% in Week 1), as is the rate of influenza-related hospitalizations among all coded hospitalizations (5.3% vs. 3.8% in Week 1). The number and proportion of flu-related visits among those under 15 continue to rise, with 587 cases and 13.3% of flu cases (vs. 419 and 11.0% in Week 1), as well as in private practice.

• Activity is increasing in private practice: 30.2% (vs. 25.3% in W-1) among SOS Médecins visits in W04; 510 consultations per 100,000 inhabitants for Sentinelles+IQVIA in W04 (vs. 392 in W-1).

• Viral circulation is rising again in private laboratories (37.3% in Q4 vs. 29.3% in Q1) and remains stable at a high level in hospitals (21.6% in Q4 vs. 20.9% in Q1).

Covid-19

• The SARS-CoV-2 virus continues to circulate at low levels in Bourgogne-Franche-Comté, as in other regions. The proportion of cases handled by SOS Médecins and emergency departments for suspected COVID-19 remains low.

• Since week 40-2024, 38 severe cases of COVID-19 (all ages) have been reported by the sentinel intensive care unit network.

Acute Respiratory Infections

• Since week 40-2024, 208 clusters of ARI cases have been reported. The number of new clusters was low between week 42 (mid-October) and week 48 (late November). The number of reports has tended to increase since then (data not consolidated in S02 and S03).

• In total, 79 ARI clusters were attributed exclusively to COVID-19 and 72 clusters were attributed exclusively to influenza, 70% of which occurred between weeks S52 and S02. Four clusters were attributed exclusively to RSV.

• Since week 40-2024, 12 episodes of COVID-19/influenza co-infection have been reported (including 3 in S51 and 3 in S01) and 4 episodes of influenza/RSV co-infection since S51. One case of COVID-19/RSV co-infection was reported in S01.