Analysis of a 3-months measles outbreak in western Liguria, Italy: Are hospital safe and healthcare workers reliable?

Abstract

Background: From January 2017 to June 2018 more than 7000 measles cases were reported in Italy, of which more than 400 among unvaccinated healthcare workers. We described a measles outbreak occurred in Western Liguria, Italy, characterized by a high involvement of healthcare workers and hospital visitors. Methods: Suspected measles cases and data regarding vaccination status and clinical management of the patients were collected by reviewing 3 different surveillance systems: the routine mandatory notification system, the National Integrated Surveillance System for Measles and Rubella and the regional reference laboratory for measles diagnosis. Results: Thirty-six cases were reported, with a median age of 31 years and >95% in unvaccinated subjects. One death occurred, 15 cases were hospitalized. Hospital transmission was confirmed or suspected in 12 cases; amongst this cases, 5 were healthcare workers (a gynaecologist, an obstetric nurse, a radiologist, a physiotherapist and a nurse working in an infectious disease ward), all certified unvaccinated. Phylogenetic analysis revealed the circulation of a single B3 genotype variant. Conclusions: Our experience highlighted the key role of nosocomial transmission and the need for targeted strategies, in particular (i) to implement a measles catch-up immunization campaign in susceptible groups, especially in healthcare workers, (ii) to intensify the check of immunisation status of healthcare workers and to offer vaccination for those who need it, (iii) to improve timeliness and completeness of surveillance systems. Efforts are needed to guarantee the safety of the hospital and the reliability of the healthcare workers. Only high vaccination coverage among HCWs can prevent the diffusion of measles in the hospital setting. Keywords: Measles outbreak, Epidemiological surveillance, Laboratory surveillance, Healthcare workers, Nosocomial transmission