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SARS-CoV-2 Antibody Kinetics in Unvaccinated Hospitalized Children With COVID-19
Dimitra Dimopoulou1, Marietta Charakida1, Antonios Marmarinos2
1From the Second Department of Paediatrics.
Insights
COVID-19 infection in children leads to durable antibody responses, with severity impacting antibody levels but not age. Most children maintain detectable IgG levels one year post-infection, indicating lasting humoral immunity.
Area of Science:
- Immunology
- Pediatrics
- Infectious Diseases
Background:
- Antibody levels wane months after acute COVID-19, yet humoral memory endures in adults.
- Factors like age and disease severity may influence antibody responses post-infection.
- Understanding antibody durability in children after COVID-19 is crucial for assessing long-term immunity.
Purpose of the Study:
- To evaluate the presence and durability of antibody responses in children hospitalized with COVID-19.
- To assess the impact of age and disease severity on antibody levels and persistence.
Main Methods:
- Prospective, single-center study of unvaccinated children (0-16 years) hospitalized with COVID-19.
- Serological testing for anti-Spike SARS-CoV-2 IgG and neutralizing antibodies at diagnosis and 1, 3, 6, and 12 months post-infection.
- Analysis of antibody levels in relation to age, time post-infection, and disease severity.
Main Results:
- High seropositivity rates observed at 3 months (91%), 6 months (85%), and 12 months (83%) post-infection.
- SARS-CoV-2 IgG levels significantly decreased over time but were not influenced by age.
- Higher disease severity was associated with lower SARS-CoV-2 IgG levels at follow-up.
Conclusions:
- COVID-19 infection induces durable seroconversion in children, with detectable IgG levels persisting up to one year.
- Disease severity, not age, is a significant factor influencing antibody titers in pediatric COVID-19 patients.
- The findings suggest robust and long-lasting humoral immunity following SARS-CoV-2 infection in children.
Background:
Antibody levels decline a few months post-acute COVID-19, but humoral memory persists in adults. Age and disease severity may affect antibody responses. This study aims to evaluate the presence and durability of antibody responses in children with COVID-19.
Methods:
A prospective, single-center study, involving unvaccinated children 0-16 years of age who were hospitalized with COVID-19 between October 2020 and December 2021, was conducted. Serological testing for anti-Spike severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG and neutralizing antibodies was performed at diagnosis and at 1-, 3-, 6- and 12-months post-infection.
Results:
A total of 65 immunocompetent children were enrolled [mean age (±SD): 6.7 (±6.4) years; males: 56.9%]. At 3 months, 40/44 (91%) children were seropositive; seropositivity persisted in 22/26 (85%) children at 6 months and in 10/12 (83%) children at 12 months. There was no evidence that age was modifying the prediction of variance of SARS-CoV-2 IgG levels. In contrast, SARS-CoV-2 IgG levels varied with time and disease severity. The association with time was non-linear, so that with increasing time there was a significant reduction in SARS-CoV-2 IgG levels [coef, 0.044 (95% confidence interval {CI}: 0.061-0.028), P < 0.001]. For each increment of time, the higher disease severity group was associated with 0.9 lower SARS-CoV-2 IgG levels. Everyone varied from the average effect of time with an SD of 0.01, suggesting that individuals may have different trajectories across time.
Conclusion:
Disease severity, but not age, influences antibody titers among children hospitalized with COVID-19. SARS-CoV-2 infection induces durable seroconversion in these children with detectable IgG levels at 1 year after infection.
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