Preventive Efficacy, Safety, Immunogenic Activity, and Evaluation of Post-Vaccination Responses Following Immunization with Combined Trivalent Vaccine Vaktrivir (Measles-Rubella-Parotitis) in Premature Infants

Background . Registration of combined trivalent vaccine Vaktrivir (measles-rubella-parotitis) in Russia necessitates studies on its preventive efficacy, safety, immunogenic activity, and post-vaccination responses following the immunization of premature infants. Objective. The aim of the study is to evaluate efficacy, safety, and immunogenic activity of combined trivalent vaccine (measles-rubella-parotitis) and level of post-vaccination responses following the immunization of premature infants. Methods . Experimental studies were conducted to evaluate safety, immunogenicity, and postvaccinal responses after immunization of premature infants with combined within prospective comparative clinical observation. Results . Administration of the combined trivalent vaccine Vaktrivir (measles-rubella-parotitis) in premature infants has shown: no cases of measles, rubella or parotitis among vaccinated persons within prospective clinical observation for 2 years; no disturbances in parameters of clinical blood analysis, biochemical blood count, total IgE, IgA, IgM, IgG (immunogram), or urine analysis among vaccinated children over time; no subjective perceptions, adverse events signs at physical examination among vaccinated compared to baseline parameters; low post-vaccination reactions (6.7%) and similar tolerance of trivalent vaccine Vaktrivir among full-term infants (3.3%) (p = 0.301). Conclusion . Administration of the combined trivalent vaccine Vaktrivir (measles-rubella-parotitis) in premature infants has demonstrated high safety profile and immunogenic properties for measles, rubella and parotitis components, good tolerability, and low post-vaccination responses after immunization, comparable to vaccination of full-term infants.