Measles Seroprevalence Among Healthcare Workers in a Tertiary Hospital in Central Greece, 2017

Measles remains a significant occupational hazard in healthcare settings. In the context of the 2017-2018 measles outbreak in Greece and amid an outbreak at the study hospital, this seroprevalence study aimed to identify gaps in measles serologic status among healthcare workers in a tertiary hospital in central Greece.

We conducted a seroprevalence study among hospital employees between February and December 2017. Blood samples and data on sociodemographic and work-related characteristics were collected from a convenience sample of participants. Measles IgG and IgM antibodies were measured using the ELISA method to determine seropositivity. The 95% CIs for measles IgG seronegativity proportions were calculated using the Clopper-Pearson exact method. Associations between participant characteristics and measles antibody status were assessed using Firth's penalized logistic regression models.

A total of 336 healthcare workers participated in the study (response rate: 24.9%). Overall, 5.4% (95% CI: 3.2-8.3) tested negative for measles IgG antibodies. No significant associations were observed between participants' characteristics and measles IgG antibody status. Male participants had 15.8 times higher adjusted odds of testing positive for measles IgM antibodies compared with female participants (aOR: 15.8; 95% CI: 2.33-107.54; p = 0.005).

Our results indicate a low-but not negligible-proportion of IgG measles seronegativity among participants. The detection of seronegative individuals born prior to 1970 challenges the assumption of universal natural immunity based solely on year of birth. Given the recent rise in measles outbreaks and the limited seroprevalence data among healthcare workers in Greece, these findings provide valuable data to support ongoing efforts to achieve full vaccination coverage in this group. Further research is warranted to investigate the observed sex differences in susceptibility to measles infection.