Paediatria Croatica, Vol. 67 No. 3-4, 2023.
Original scientific paper
https://doi.org/10.13112/PC.2023.9
The course of COVID-19 in school-aged children depends on the state of humoral immunity against diphtheria
Halyna Pavlyshyn
Olha Panchenko
; , I. Horbachevsky Ternopil National Medical University
Kateryna Kozak
Iryna Avramenko
Olha Dyvonyak
Abstract
Introduction: There is evidence that high titers of diphtheria antibodies are more often associated with an asymptomatic or less severe course of COVID-19. The aim of the study was to determine the features of the COVID-19 course in school-aged children depending on the state of postvaccination immunity against diphtheria toxin.
Methods. In total, 90 children aged 6 to 18 years were examined: 60 patients with confirmed SARS-CoV-2 infection and 30 children
without signs of the disease (control group). There were 20 patients with a mild COVID-19 course, 31 patients with moderate disease
severity and 9 patients with severe disease severity. All children were tested for the level of immunoglobulin G (IgG) against diphtheria
toxin by immune-enzymatic analysis.
Results. Total serum immunoglobulin G against diphtheria toxin was 0.431 (0.113; 0.828) IU/mL. Antitoxic immunoglobulin G was
2.5 times higher in children in the control group than in patients with SARS-CoV-2 infection. A decreased level of immunoglobulin G
was associated with increased disease severity. In children with specific IgG 0.01-0.2 IU/mL revaccination is recommended; therefore,
4.2% of the children in the control group, 6.8% with a mild COVID-19 course, 50% with moderate disease severity and 100% of children with severe COVID-19 needed a booster dose of diphtheria toxoid. A moderate negative correlation was observed between the
level of immunoglobulin G against diphtheria toxin and ESR (r=-0.38, p=0.004), CRP (r=-0.32, p=0.021), D-dimer (r =-0.35, p=0.009),
duration of hyperthermia (r=-0.49, p=0.003), and duration of treatment (r=-0.43, p=0.012).
Conclusions. Children with manifested SARS-CoV-2 infection had significantly lower levels of immunoglobulin G against diphtheria
toxin compared to the control group, indicating a lower level of humoral immunity. Children with a mild course of COVID-19 had a
significantly higher level of specific IgG against diphtheria toxin than those with a moderate and severe disease course.
Keywords
child; COVID-19; diphtheria; immunity, humoral
Hrčak ID:
317026
URI
Publication date:
21.12.2023.
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