Seroprevalence of measles antibodies in healthcare professionals in a Central Hospital in Portugal

Abstract

Introduction: Immunity against measles may result from previous contact with the virus or vaccination. In this study we aimed to evaluate the prevalence of immunity to measles in healthcare professionals of a central hospital. Material and Methods: Retrospective study, with description of the results of measles-specific IgG assay in healthcare professionals, between May 2010 and March 2018. Results: The results of 1339 healthcare professionals were analyzed. The average age was 39.3 ± 10.11 years, 71.1% female. The prevalence of positive IgG was 81.5%, higher among professionals in the age groups 40 - 49 and over 50 years (91.9% and 94.6% respectively). Healthcare professionals who presented negative or equivocal IgG were mostly under 40 years old (83.1%) (p < 0.05). Discussion: The prevalence of serological immunity to measles in healthcare professionals was found to be lower than in other studies. That may be due to differences between the characteristics of the studied samples. Susceptibility to measles was higher in lower age groups. These results may reflect low vaccination coverage in this age group, an incomplete vaccination schedule, or the possibility of older healthcare professionals having the disease, which may confer an immune response with higher IgG levels. Conclusion: Knowing the prevalence of susceptibility to measles in healthcare professionals enabled the establishment of prevention strategies for outbreaks that may occur. Vaccination remains the best preventative measure, but a third dose of vaccine may be considered in certain epidemiological contexts, particularly in the youngest exposed healthcare professionals.