Measles immunity in medical workers in Kazan

Abstract

BACKGROUND: The epidemiological situation with measles remains unstable, with periodic increases in morbidity. In the Russian Federation, as well as in other countries, cases of nosocomial infection continue to be registered. Medical workers may be involved in the epidemic process and serve, among other things, as a source of infection for patients. AIMS: assessment of postvaccinal immunity to measles in medical workers in Kazan during its elimination period. MATERIALS AND METHODS: A cross-sectional study of immunity to measles was conducted in 515 employees of medical institutions in Kazan. 376 medical staff had documented ever-evidence of immunization against measles. Measles class G immunoglobulin levels were determined, specific immunity strength was assessed as a function of age, and time since the last vaccine dose was administered. Relative values (fractions, %) and standard error of the fraction (%) were calculated. A correlation analysis was performed. RESULTS: The proportion of seropositive medical workers was 81% (95% CI 79.382.7) of all those examined. Those over 50 years of age were the most protected: antibodies were detected in 90.3% (95% CI 85.9694.64) of them. Among the 417 persons with antibodies low level was detected in 60.9% (95% CI 56.1265.68), medium level ― in 34.5% (95% CI 29.8439.16), high level ― only in 4.6% (95% CI 2.546.66) of the examined persons. In all age groups, the share of persons with low levels of protective antibodies was the highest. High level of protective antibodies was registered only in the age groups 4049 years and 50 years and older ― 4.8% (95% CI 0.988.62) and 7% (95% CI 3.2610.74), respectively. Antibody levels correlated inversely with time since vaccination (p 0.05). CONCLUSIONS: The results of serologic study of health workers demonstrate insufficient protection of health workers against measles, especially in younger groups. Decreased immunity in vaccinated health workers 10 or more years after immunization necessitates the monitoring of antibody levels in this group and consideration of revaccination.