For the week of 2 to 8 November 2026, laboratories reported 65 cases of flu in Luxembourg, compared with 64 the previous week. The figure has barely changed, while confirmed COVID-19 cases rose from 83 to 110 and cases of RSV, respiratory syncytial virus, from 5 to 13. These counts relate to three different viruses and do not necessarily represent three distinct groups of people.
The weekly report from the Health Directorate, published on 12 November, distinguishes between laboratory reports and the viral concentration measured in wastewater. For SARS-CoV-2, the two indicators are moving in opposite directions here: reported cases are rising, while the concentration detected in wastewater is falling. This juxtaposition is not a contradiction: the measures do not count the same things and, on their own, cannot be used to reconstruct the total number of people infected.
| Virus: cases reported by laboratories | Week 44 | Week 45 |
|---|---|---|
| Flu | 64 | 65 |
| SARS-CoV-2 | 83 | 110 |
| Respiratory syncytial virus | 5 | 13 |
Week 45 covers the period from 2 to 8 November 2026.
Flu remains at a low level
The 65 cases of flu reported in week 45, compared with 64 in week 44, place the indicator at a low and stable level. The Health Directorate says that this trend is similar to that observed in previous years at the same time of year. The figure is therefore not enough to signal an established epidemic, and the report does not issue a national alert.
Of the typed results, 92% relate to influenza A and 8% to influenza B. This breakdown applies to samples for which the type was determined. The statement does not specify their number here and does not detail the subtypes of influenza A.
A weekly count of cases reported by laboratories is a surveillance reference point, not an exhaustive count of all infections in the country. It depends on the people who have been diagnosed and on infections that have been reported. The number of cases, without a denominator or the number of tests carried out, gives neither a positivity rate nor an individual risk.
COVID-19: two indicators, two trajectories
Positive SARS-CoV-2 cases reported by laboratories rose from 83 to 110, an increase of 33% compared with the previous week, according to the ministry. In the same report, the viral concentration detected in wastewater fell. The case figure describes reported individual results; the wastewater measurement is a population-level indicator. These observations can complement each other, but they are not interchangeable counts.
For this week, the statement does not give the number of tests that would make it possible to compare positive results with all tests carried out. Nor does it publish hospitalisation or death figures in this weekly report. It is therefore possible to read the rise in reported cases, but not to infer from it alone the severity of the situation or the trend in the total number of infections.
The difficulty of distinguishing respiratory infections from symptoms alone helps explain the value of laboratory confirmation for surveillance. The World Health Organization notes that several viruses, including flu, SARS-CoV-2 and RSV, can cause similar symptoms. This general point explains a limitation of clinical diagnosis; it is not a testing instruction for everyone with symptoms.
RSV remains uncommon in the figures
Laboratories reported 13 cases of RSV in week 45, compared with 5 the previous week. The Health Directorate describes the level as low and says it remains slightly below that observed in previous years at the same time of year. The increase from 5 to 13 is a rise in the number of cases, but starting from a small figure makes proportional changes particularly sensitive. Here, the level and the comparison with previous seasons are more informative than a striking percentage.
The ministry says the coming weeks will show whether this is the start of an upward trend. This is a matter of monitoring, not a forecast of a peak or a date for the start of an epidemic. One week alone is not enough to tell whether the rise will continue.
Following the rest of the season indicator by indicator
For readers, the useful approach is to follow each virus separately and compare equivalent periods. This week, flu is stable at a low level; reported COVID-19 cases are rising while the wastewater indicator is falling; RSV remains at a low level despite an increase in the number of reported cases. None of these points, on its own, sums up all respiratory infections.
The next weekly reports will show whether these trajectories are confirmed. The Health Directorate publishes the Luxembourg figures; the WHO provides general context on flu diagnosis. These sources do not have the same role: national monitoring provides information on the week observed, while the WHO’s explanation addresses the general difficulties of distinguishing between viruses.
References
- Health Directorate, report for the week of 2 to 8 November 2026
- World Health Organization, seasonal influenza and diagnosis
- L’essentiel, flu cases stabilise in Luxembourg
Cultured human nasal cells infected with influenza A virus, viewed under an electron microscope and shown in false colour. Scientific illustration.
Connor Thompson / Phage1990 — SEM micrograph of influenza A virions infecting primary human airway organoid cultures showing differentiated cilia — Wikimedia Commons — CC BY 4.0.
