Number of reported cases of RSV, COVID-19 and flu in 2025-2026; Credit: MSAN

On Thursday 8 January 2026, the Health Directorate of Luxembourg's Ministry of Health and Social Security published its weekly overview of the evolution of major acute respiratory infections, including COVID-19, influenza (flu) and respiratory syncytial virus (RSV), covering the period from Monday 29 December 2025 to Sunday 4 January 2026.

Increase in flu cases

During week 1, the number of flu cases reported by laboratories increased from 550 to 630 cases, representing a rise of 15% compared to the previous week. Influenza A accounted for 99.5% of the typed results, while influenza B represented 0.5%.

The Ministry of Health and Social Security recalled that vaccination is still available and remains the most reliable means of preventing seasonal flu and reducing the risk of complications. The vaccination recommendation primarily concerns people aged 65 and over, who are at the highest risk of flu-related complications.

Slight decrease in RSV cases

The number of confirmed RSV cases decreased slightly by 4%, from 150 to 144 cases. Since October 2025, 68% of RSV infections have affected children under ten years of age, indicating that the virus primarily affects younger age groups.

Decrease in COVID-19 / SARS-CoV-2 cases

The number of positive COVID-19 cases decreased from 70 to 62 cases, representing a reduction of 11% compared to the previous week. At the same time, the viral concentration detected in wastewater has decreased.

The latest available sequencing data reveal that the XFG variant (40.6%), its sub-variant XFG.3 (23.9%) and the NB.1.8.1 variant (23.9%) remain predominant.

The ministry recommended the following preventative measures to limit the spread of viruses:

  • wash hands regularly with soap and water for 30 seconds, thoroughly rubbing the palms, fingers, backs of hands and under the nails;
  • cover one's mouth and nose with a tissue when coughing or sneezing - or use the crook of the elbow;
  • immediately throw used tissues in the rubbish bin and then wash one's hands;
  • avoid physical contact such as hugs, kisses and handshakes;
  • avoid crowds and gatherings during the epidemic season;
  • stay home if sick to avoid infecting others;
  • ventilate rooms regularly, at least three to four times a day for ten minutes.