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Updated: Nov 3, 2025
Merkel Cell Polyomavirus Infection and Detection
Published on: February 7, 2019
Diagnostic challenges and pockets of susceptibility identified during a measles outbreak, Luxembourg, 2019
Michel Kohnen1,2, Patrick Hoffmann3, Caroline Frisch3
1Clinical laboratory, Centre Hospitalier de Luxembourg, Luxembourg, Grand Duchy of Luxembourg.
Abstract:
Luxembourg was among the first countries in the World Health Organization (WHO) European Region documenting interruption of endemic measles transmission, but an increased incidence was registered in spring 2019. The outbreak started with an unvaccinated student who had been to a winter sports resort in a neighbouring country, where a measles outbreak was ongoing. Subsequently, 12 secondary and two tertiary cases were confirmed among students from the same school, relatives and healthcare workers, as well as six probably unrelated cases. Only 11 cases initially fulfilled the WHO definition for suspected measles cases. Fourteen of 20 cases with information on country of birth and the majority of unvaccinated cases (10/12) were born outside of Luxembourg. Measles IgM antibody results were available for 16 of the confirmed cases, and five of the eight IgM negative cases had been vaccinated at least once. All 21 cases were PCR positive, but for three previously vaccinated cases with multiple specimen types, at least one of these samples was negative. The outbreak highlighted diagnostic challenges from clinical and laboratory perspectives in a measles elimination setting and showed that people born abroad and commuters may represent important pockets of susceptible people in Luxembourg.
Insights
Luxembourg experienced a measles outbreak in 2019, despite prior elimination. The study highlights challenges in diagnosing measles and identifies unvaccinated individuals, including foreign-born residents and commuters, as key susceptible populations.
Area of Science:
- Epidemiology
- Infectious Diseases
- Public Health
Background:
- Luxembourg achieved measles elimination in the WHO European Region.
- An increase in measles incidence occurred in spring 2019.
- The outbreak was linked to international travel and ongoing measles transmission in a neighboring country.
Purpose of the Study:
- To investigate the measles outbreak in Luxembourg in 2019.
- To identify challenges in measles case detection and diagnosis.
- To understand the role of susceptible populations, including foreign-born individuals and commuters.
Main Methods:
- Retrospective analysis of measles cases reported in spring 2019.
- Clinical case review and laboratory confirmation (PCR, IgM antibody testing).
- Epidemiological investigation including vaccination status and country of birth.
Main Results:
- 21 measles cases were confirmed, originating from an unvaccinated student returning from abroad.
- A significant proportion of cases were born outside Luxembourg (14/20).
- Diagnostic challenges were noted, with some vaccinated individuals testing IgM negative and PCR results varying across specimen types.
Conclusions:
- The outbreak underscored diagnostic complexities in a measles-free setting.
- Unvaccinated individuals, particularly those born abroad and commuters, represent important reservoirs of susceptible populations.
- Enhanced surveillance and targeted vaccination strategies are crucial for maintaining measles elimination.
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