Measles outbreaks among health workers in a university hospital admission ward in Northeastern Thailand in 2019: reflections on the occupational health management system

Objectives This study examined a measles outbreak among health workers in a university hospital admission ward and details of the existing occupational health management system. Methods Secondary data was obtained from two sources: 1) from the Occupational Health and Safety Office outbreak investigation report a post-exposure immunity evaluation which is completed after a measles, mumps, or rubella outbreak and 2) from the medical records of the individual cases. In addition, the Occupational Health and Safety Office guidelines were reviewed and a descriptive epidemiological investigation was conducted. Results A total of 75 health workers in the university hospital admissions ward who were potentially exposed were included in the study, of whom three were diagnosable as measles based on a positive immunoglobulin M (IgM) test. The three health workers who were identified as confirmed cases were nursing assistants; two worked in the admissions ward 4A, and one worked in the cardiac care unit. We found evidence that a propagated source caused the outbreak. The occupational health management system in the hospital at that time had only exposure and post-exposure protocols, but no pre-exposure protocol. Conclusion None of the health workers who were diagnosable as measles had been examined for measles immunity during their pre-placement health examination. The occupational health management system should revise the policy for ensuring the immunity to measles of health workers before allowing them to begin work and conducting a respirator fit test before using an N95 respirator.