Safety of antibodies to measles, mumps, rubella and diphtheria in patients with juvenile idiopathic arthritis

Introduction . The issue of protection against vaccinepreventable diseases has acquired new urgency in connection with the decrease in the vaccination rate established by WHO against the background of the COVID-19 pandemic. This creates the conditions for outbreaks and puts patients with immunopathological diseases at particular risk, who are most often not vaccinated from the moment of diagnosis Purpose of the study – to assess the safety of specific antibodies to measles, mumps, rubella and diphtheria in children with JIA, depending on the duration of vaccination, the duration of the disease and the therapy received. Materials and methods . The vaccination rate of 171 children with juvenile idiopathic arthritis (JIA) aged (11,31±0,31 years) with the duration of the disease at the time of examination was 4,69±0,29 years, who had previously received 1-2 vaccinations against measles, mumps, rubella and 3-6 vaccinations against diphtheria. Antibodies to these infections were determined by ELISA. Results . 42.1% of children had no protective titers of antibodies to measles, 19,9% – to mumps, 9,4% – to rubella and 16,4% – to diphtheria. Among 93 vaccinated and revaccinated patients, there were no protective titers of antibodies to measles – 40,9% (38 children), mumps – 13,9% (13 people), rubella – 5,4% (5 children), and among 78 vaccinated once, respectively: measles – 43.6% (34 children), mumps – 25.6% (20 children), rubella – 14,1% (11). The level of protection against diphtheria was comparable for those who received 3-5 vaccinations. Depending on the therapy, 3 groups were identified: group 1-71 children received metatrexate and glucocorticosteroids, 2-82 children received modifying anti-rheumatic drugs (DMARD) and 18 children without this therapy (Group 3). Children of the 2nd group were on average older (12,48±0,42 years) than in the 1st and 3rd groups (10,04±0,48 and 10,96±0,96 years, respectively), they had significantly more frequent systemic variant and polyarthritis (64,6% compared to 36,6% and 16,7%, px2˂0,001). The number of vaccine doses received by children in all groups before the onset of the disease did not significantly differ. The average level of antibodies to measles in children of group 2 (0,32±0,07 IU/ml) was 2,8 times less than in group 3 and significantly less than in group 1 (0,78±0,16, Pt=0.009), the