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Antibody response against SARS-CoV-2 variants of concern in children infected with pre-Omicron variants: An
Vanesa Seery1, Silvina Raiden2, Constanza Russo1
1Instituto de Investigaciones Biomédicas en Retrovirus y SIDA (INBIRS). Facultad de Medicina. UBA-CONICET, Paraguay 2155, C1121ABG Caba, Argentina.
Insights
Children infected with SARS-CoV-2 show a stronger and longer-lasting antibody response than adults. Vaccination further boosts this immune response in children, indicating potential for optimized pediatric COVID-19 vaccination strategies.
Area of Science:
- Immunology
- Infectious Diseases
- Pediatrics
Background:
- Pediatric COVID-19 is often asymptomatic or mild, yet typically elicits an antibody response.
- Previous studies show conflicting data on pediatric versus adult antibody responses (strength, specificity, durability).
Purpose of the Study:
- To compare the antibody response in unvaccinated infected children and adults.
- To evaluate the impact of vaccination on the antibody response in previously infected children.
Main Methods:
- Observational study of three cohorts: unvaccinated infected children (n=115), unvaccinated infected adults (n=62), and vaccinated infected children (n=76).
- Analysis of plasma anti-spike IgG antibodies and neutralizing activity against SARS-CoV-2 variants (Wuhan, Delta, Omicron) 7-17 months post-infection.
Main Results:
- Over 95% of both unvaccinated children and adults remained seropositive at 13-14 months post-infection.
- Children exhibited higher anti-spike IgG titers and neutralizing activity against all variants compared to adults.
- Vaccination in previously infected children significantly enhanced antibody titers and neutralizing activity.
Conclusions:
- Unvaccinated infected children develop a more potent and durable antibody response than adults.
- Vaccination further amplifies the antibody response in children, suggesting a need for further research into optimized pediatric vaccination strategies against evolving SARS-CoV-2 variants.
Background:
Despite that pediatric COVID-19 is usually asymptomatic or mild, SARS-CoV-2 infection typically results in the development of an antibody response. Contradictory observations have been reported when the antibody response of children and adults were compared in terms of strength, specificity and perdurability.
Methods:
This observational study includes three cohorts infected with SARS-CoV-2 between March 2020-July 2021: unvaccinated infected children (n=115), unvaccinated infected adults (n=62), and vaccinated infected children (n=76). Plasma anti-spike IgG antibodies and neutralising activity against Wuhan, Delta and Omicron variants after 7-17 months post-infection were analysed.
Findings:
More than 95% of unvaccinated infected children and adults remained seropositive when evaluated at 382-491 and 386-420 days after infection, respectively. Anti-spike IgG titers and plasma neutralising activity against Wuhan, Delta and Omicron variants were higher in children compared to adults. No differences were found when unvaccinated infected children were stratified by age, gender or presence/absence of symptoms in the acute phase of SARS-CoV-2 infection, but a slight decrease in the antibody response was observed in those with comorbidities. Vaccination of previously infected children with two doses of the inactivated BBIBP-CorV or the mRNA vaccines, BNT162b2 and/or mRNA-1273, further increased anti-spike IgG titers and neutralising activity against Wuhan, Delta and Omicron variants.
Interpretation:
Unvaccinated infected children mount a more potent and sustained antibody response compared with adults, which is significantly increased after vaccination. Further studies including not only the analysis of the immune response but also the effectiveness to prevent reinfections by the different Omicron lineages are required to optimise vaccination strategy in children.
Funding:
National Agency for Scientific and Technological Promotion from Argentina (PICTO-COVID-SECUELAS-00007 and PMO-BID-PICT2018-2548).
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