Pre-booster and post-booster seroprevalence of measles antibodies among employees of the Olomouc University Hospital - a pilot study

Introduction: The increase in measles cases in early 2019 led to the implementation of several preventive measures focused mainly on health care providers. The study aimed to evaluate the seroprevalence of measles antibodies among employees of a large hospital and, a year apart, the rate of seroconversion in a pilot sample of the revaccinated subjects. Methods: In 3027 employees of the University Hospital Olomouc, specific immunoglobulin G levels were tested on a voluntary basis. Those with insufficient levels were offered a booster dose. About approximately one year after the booster dose, the same test was performed in a sample of 52 employees. Results: Of the tested subjects with a mean age of 41.8 +/- 9.2 years, 54.0% were seropositive. A higher proportion of seropositivity as well as higher absolute values of antibody titers were noted in those born before routine vaccination was introduced in 1969. A total of 80.9% of the seronegative subjects opted for a booster dose. Seroconversion occurred in 73.2% of retested subjects. The relative increase of post-booster antibody titers was moderately correlated with age (r = 0.47, p < 0.05). Conclusion: The proportion of seronegative employees of a large hospital reached 46.0%, being higher in younger individuals. Seroconversion occurred in 73.2% of booster dose recipients included in a pilot sample for reanalysis. A statistically significant correlation was noted between the relative increase of antibody titers and age.