Measles outbreak transmission in the ER waiting room: the role of vaccination.

Background: Measles is one of the most contagious infectious diseases. Spain was declared free of endemic measles transmission in 2017. However, less than half of EU/EEA countries have achieved vaccination coverage goals and measles outbreaks have been reported recently, some of them in healthcare facilities. The aim of this study was to present an outbreak in the pediatric emergency (ER) waiting room affecting a vaccinated healthcare worker.

Methods: Descriptive study of an outbreak whose transmission occurred in the pediatric ER waiting room of a tertiary level hospital on the island of Tenerife (Canary Islands) in April 2024.

Results: Between April 23 and May 12, 2024, four PCR-confirmed measles cases were identified, resulting in 407 contacts in healthcare center waiting rooms. One of the cases was a 26-year-old male nurse who had been correctly vaccinated with two doses of measles, mumps, and rubella vaccine during childhood. Between May 7 and 10, during his infective period, he took two two-and-a-half-hour flights and lived together with nine people during a trip. No evidence of infection has been identified among the individuals with whom he lived neither the passengers and crew of the two flights.

Conclusions: In the emergency waiting room, an unvaccinated girl gave measles to two infants who were not yet old enough to be vaccinated and to a nurse who had been properly vaccinated as an infant. Despite generating more than 300 close contacts, the nurse did not infect anyone, suggesting that vaccination may help prevent both infection and transmission of measles.