Number of reported cases of RSV, COVID-19 and flu in 2025-2026 (Week 4); Credit: MSSS

On Thursday 29 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) for the week of Monday 19 to Sunday 25 January 2026 (week 4).

Drop in flu cases

During week 4, the number of flu cases reported by laboratories decreased from 872 to 740, a 15% drop compared to the previous week. Despite this second consecutive week of decline, the virus continues to circulate widely.

During the last week, influenza A attributed for 99.9% of cases, while influenza B represented 0.1%.

The Ministry of Health and Social Security recalled that vaccination is still available. This recommendation primarily concerns people aged 65 and over, who are at the highest risk of complications from the flu. The ministry noted that vaccination remains the most reliable way to prevent seasonal flu and reduce the risk of associated complications.

Decrease in RSV cases

The number of confirmed RSV cases also dropped over one week, from 145 to 125 - a decrease of 14%. Since October 2025, 58% of infections have affected children under the age of ten, indicating that the virus primarily affects younger people.

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

The number of positive COVID-19 cases increased from 65 to 88 - up by 35% compared to the previous week. Meanwhile, the viral concentration detected in wastewater decreased slightly.

The latest available sequencing data reveals that the XFG variant (45.5%), its sub-variant XFG.3 (26.7%) and the NB.1.8.1 variant (18.2%) are 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;
  • throw used tissues in the rubbish bin immediately 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.