[An outbreak of measles at an emergency room]

Area of Science:

• Epidemiology
• Infectious Diseases
• Public Health

Background:

• Measles outbreaks pose a significant risk in healthcare settings, particularly for unvaccinated or under-vaccinated staff.
• The Dutch National Immunisation Programme aims to prevent measles, but its effectiveness against nosocomial transmission requires evaluation.

Observation:

• A measles outbreak in a hospital involved an aircrew member and three infected staff members with varying vaccination histories.
• Two unvaccinated staff members and one who received two doses of the measles-mumps-rubella (MMR) vaccine were infected.
• Measles virus genotype D5 was identified in all four cases, confirming a single source of infection.

Findings:

• Post-exposure MMR vaccination within 48 hours did not prevent measles in two susceptible hospital staff.
• The Dutch National Immunisation Programme did not fully protect one staff member against nosocomial measles infection.
• No further cases of measles occurred after the initial outbreak, indicating containment after the index cases.

Implications:

• Current 72-hour post-exposure immunisation policies for measles may be insufficient to prevent nosocomial spread.
• Healthcare workers, even those vaccinated through national programs, remain at risk for measles infection.
• Targeted MMR vaccination or booster programs for hospital staff in high-risk departments could enhance protection against measles.