Week 43 review - 23 to 29 October 2023

The weekly retrospective gives a summary of trends in acute respiratory infections, including COVID-19 and influenza (influenza virus) and respiratory syncytial virus (RSV).

Trends of the week:

COVID-19: Stabilisation or even a slight increase after a fall in recent weeks.

Respiratory syncytial virus (RSV): Slight acceleration in the circulation of the RSV virus, but still at a low level.

Influenza: Very few cases of flu have been detected, with circulation at a low level.


From 23 to 29 October 2023 (week 43), the number of people testing positive for COVID-19 increased to 282 cases, compared to 259 cases the previous week (+9%).

The positivity rate rose to 23% compared with 20% the previous week. The viral concentration detected in wastewater confirms the increase in circulation of the virus [1].

These 3 indicators suggest that the circulation of SARS-CoV-2 is starting to increase again following several weeks of decline. Recent sequencing data showed a preponderance of the EG.5.1 variant (38.7%) [2].


For the week of 23 to 29 October 2023 (week 43), the number of influenza cases reported by laboratories rose to 7, compared with 3 case the previous week.

This data largely overlaps with LNS sentinel surveillance, which indicates increased circulation of rhinoviruses and SARS-CoV-2, but little circulation of influenza viruses [2].

Respiratory syncytial virus (RSV)

For week 43 (23-29 October 2023), the number of respiratory syncytial virus (RSV)-positive individuals detected by laboratories rose to 18 cases, compared with 9 cases the previous week.

The circulation of the RSV virus is beginning to accelerate.

Press release by the Ministry of Health


[1] https://www.list.lu/en/covid-19/coronastep/

[2] https://lns.lu/publications/

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