Immunologic monitoring over people vaccinated against plague in Caspian sand natural focus in order to assess and manage health risks

To provide better opportunities for managing both risks caused by vaccination and risks of epidemiological complications, immunologic monitoring over people vaccinated with live dried plague vaccine (LPV) due to epidemiologic indications was performed. Our research goal was to assess whether immunologic monitoring over people vaccinated against plague yielded informative results; it was done to substantiate activities aimed at improving procedures for LPV application. Immunologic monitoring was performed from 2016 to 2019 in the Caspian sand natural plague focus according to conventional procedures for assessing humoral and cellular components in immunity. We determined immunologic parameters in 217 volunteers vaccinated with LPV and 130 healthy donors (the reference group) prior to and 1 and 12 months after vaccination. We suggested a methodical approach based on aggregated analysis of the summated immune response predictors chosen for estimation in volunteers vaccinated with LPV and giving score values to them; it allows revealing people who react to plague microbe antigens predominantly as per cellular, humoral, or mixed type. Immunologic monitoring results proved that it was safe to apply LPV; they allowed characterizing trends occurring in immunological restructuring in vaccinated volunteers, determining limits of fluctuation in individual parameters of an immune response to the vaccine, and revealing people with both normal and changed (reduced or increased) immunologic reactivity to LPV. If monitoring data are taken into account, it provides an opportunity to predict vaccination results as per epidemiological parameters, to reveal groups with normal, high, or low immune reactivity to plague microbe antigens in order to determine people in them who need an individual approach when it comes down to anti-plague vaccination.