Graph showing COVID-19 cases in 2024 week 1; Credit: MS

Luxembourg's Ministry of Health and Social Security has published a weekly retrospective that provides a summary of the evolution of acute respiratory infections, including COVID-19, influenza and respiratory syncytial virus (RSV) for the week of 1 - 7 January 2024.

The overall trends saw a decrease in the number of COVID-19 cases, a decrease in the number of RSV cases and a slight decrease in the number of flu cases.

COVID-19 / SARS-CoV-2

For week 1 from 1 to 7 January 2024, the number of people positive for SARS-CoV-2 decreased to 240 cases compared to 338 cases the previous week, a decrease of 29%.

The positivity rate decreased to 14% compared to 20% the previous week. The viral concentration detected in wastewater also decreases substantially.

These indicators suggest that the circulation of SARS-CoV-2 has decreased, which is probably linked to departures during the end-of-year school holidays.

The latest sequencing data available for weeks 48-50 show a preponderance of the JN.1 variant (60.9%) followed by the BA.2.86 variant (11.3%) and the XBB.1.9 variant (10.4%). Note that the JN.1 variant is a descendant of the BA.2.86 variant with an additional mutation on its spike protein.

Influenza 

For week 1 from 1 to 7 January 2024, the number of cases of influenza reported by laboratories decreased to 332 cases compared to 371 cases the previous week, a decrease of 11%.

These data largely overlap with LNS sentinel surveillance which indicates high circulation of the influenza virus, followed by SARS-CoV-2, rhinovirus and RSV.2

Respiratory syncytial virus (RSV)

For week 1 from 1 to 7 January 2024, the number of people positive for respiratory syncytial virus (RSV) reported by laboratories decreased to 52 cases compared to 77 cases the previous week, a decrease of 32%. The peak of the epidemic this season was reached in week 50 from 11 to 17 December 2023.