A Serosurvey Identifying Vulnerability to Measles in Health Care Workers. A Hospital-Based Prospective Seroprevalence Study
Abstract
The aim of this serological survey was to assess the persistence of measles antibodies among health care workers (HCWs) at risk of incidental measles. A prospective study of measles-specific antibodies in serumsamples obtained from a total of 2782 participants aged 19-89 years was conducted between May 2018 and December 2019.
The seropositivity rate of 93.7% (95% CI: 92.4-94.9%) in fully vaccinated participants aged 19-48 years was significantly lower than that of 98.0% (95% CI: 96.5-99.0%) in participants naturally immunised before 54 years. A cohort of those born in 1971-1975, vaccinated predominantly with one dose, showed lower seropositivity persistence (86.6%) than those fully vaccinated with two doses or naturally immunised.
Otherwise, seropositivity was not markedly influenced by sex, age, smoking status, overweight, obesity or concomitant disease. The presence of su_cient antibody levels in a high proportion of HCWs irrespective of the way they acquired immunity is a favourable finding for managing incidental measles; hence, in the presence of a risk of a measles outbreak, it would be possible to perform targeted vaccination of only at-risk HCWs with a history of incomplete vaccination or missing information about the way in which immunity is acquired.