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394 Lubimova et al. | Journal of Clinical and Translational Research 2023; 9(6): 392-397
Kolmogorov–Smirnov test, with no normal distribution identified. biologics (n = 48; 63%). Ten patients (13%) received two biologics
Description of quantitative variables was done with median and and more, consequently.
interquartile range (25%; 75%) for continuous variables and
in terms of absolute meanings and percentages for categorical 3.1.1. The predictors of the refused vaccination against
diphtheria
variables. For comparison, the categorical variables Pearson’s χ
2
test or Fisher’s exact test in case of expected frequencies <5 were The protective level against diphtheria was in 33 (%) of patients.
used, and a comparison of two quantitative variables was carried The following differences were found among patients with JIA
out using the Mann–Whitney test. P < 0.05 was considered who continued to be vaccinated against diphtheria. Patients
statistically significant. with a less severe course of JIA, who received methotrexate less
often, who needed less both primary administration of biologics
2.4. Ethics and switching between biologics more often continued to be

Written consent was obtained according to the Declaration of vaccinated. We did not observe the association of vaccination
Helsinki. The Ethics Committee of Saint Petersburg State Pediatric refusal, depending on the type of biologic. Vaccination against
Medical University (protocol number 9/2 from September 2, diphtheria was effective, as evidenced by the almost two-fold
2019) approved this retrospective study’s protocol. All patients or prevalence of patients with a protective antibody titer compared
patients’ representatives (for patients under the age of 15) gave to those who refused revaccination. Data are in Table 1.
their consent in their case report forms authorizing the anonymous 4. Discussion
use of their medical information. All patients were appropriately
anonymized. Many children with rheumatic diseases in the Russian
Federation stop being vaccinated after diagnosis [21]. A lot
3. Results of practicing pediatricians and pediatric rheumatologists are
3.1. Patients’ demography unreasonably afraid of post-vaccination complications, and flares
of rheumatic disease, and also consider vaccination ineffective
The studied population was presented with girl predominance when using immunosuppressive therapy. Often they do not take
(n = 48; 63%), oligoarticular (n = 31; 41%), and polyarticular into account the fact that prolonged use of immunosuppressive
(n = 30; 40%) predominance. Treatment modalities included drugs, escalation of treatment regimens, and the presence of
corticosteroids (n = 33; 43%), methotrexate (n = 71; 93%), and signs of immune dysfunction leads to an altered “protective”

Table 1. Patients demography and post-vaccination immunity against diphtheria in children with JIA
Parameter Vaccination against diphtheria Р
Continued (n=25) Declined (n=51)
Demography
Sex, males, n (%) 12 (48) 16 (31) 0.158
JIA onset age, years, Me (25%; 75%) 5.0 (4.1; 6.5) 5.1 (3.0; 11.4) 0.820
Age of inclusion in the study, years, Me (25%; 75%) 11.6 (9.8; 16.0) 13.8 (11.0; 15.8) 0.670
JIA duration, years, Me (25%; 75%) 6.5 (4.9; 8.2) 6.2 (3.6; 9.5) 0.699
JIA courses
Oligoarthritis, n (%) 11 (44) 20 (39) 0.678
Polyarthritis, n (%) 8 (32) 22 (43)
Systemic arthritis, n (%) 1 (4) 3 (6)
Vaccine diphtheria status
Antibodies against diphtheria, IgG, IU/ml, Me (25%; 75%) 0.14 (0.07; 0.34) 0.06 (0.02; 0.22) 0.695
Patients with protective levels of antibodies against diphtheria, n (%) 15 (60) 18 (35) 0.041
Time since the last diphtheria vaccination, years, Me (25%; 75%) 5.6 (3.6; 10.3) 6.7 (4.0; 10.7) 0.025
Treatment
Corticosteroids, n (%) 4 (16) 16 (31) 0.153
Methotrexate, n (%) 21 (84) 50 (98) 0.020
Methotrexate duration treatment, years, Me (25%; 75%) 3.1 (1.6; 5.8) 5.1 (2.6; 8.7) 0.027
Biologics, n (%) 10 (40) 38 (75) 0.003
Biologics duration treatment, years, Me (25%; 75%) 1.9 (1.0; 4.1) 3.4 (2.6; 8.7) 0.674
Using > one biologics, sequentially, n (%) 1/9 (11) 9/29 (31) 0.009
Abbreviations: JIA: Juvenile idiopathic arthritis; Me: Median
Serious adverse events, as well as JIA flares in 3 months after vaccination were not observed. We found that methotrexate odds ratio [OR]=9.5 (95% confidence interval [CI]: 1,004; 90.3) and
biologics OR=4.4 (95% CI: 1.6; 12.1) were predictors of refusal of revaccination against diphtheria.
DOI: http://dx.doi.org/10.18053/jctres.09.202306.23-00103