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Vaccine Effectiveness Against Long COVID in Children
Hanieh Razzaghi1, Christopher B Forrest1,2, Kathryn Hirabayashi1
1Applied Clinical Research Center, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.
Insights
COVID-19 vaccination offers moderate protection against long COVID in children and adolescents. Vaccine effectiveness is higher in adolescents and wanes over time, necessitating further research.
Area of Science:
- Pediatric infectious diseases
- Vaccinology
- Public health
Background:
- COVID-19 vaccination is established to reduce acute illness in children.
- The protective effect of vaccination against long COVID in pediatric populations remains less understood.
- Long COVID presents a significant public health challenge in children and adolescents.
Purpose of the Study:
- To estimate the vaccine effectiveness (VE) against long COVID in children aged 5 to 17 years.
- To analyze VE against both probable (symptom-based) and diagnosed long COVID.
- To investigate variations in VE based on age group and time since vaccination.
Main Methods:
- Retrospective cohort study utilizing electronic health records from 17 health systems.
- Inclusion of over 1 million children aged 5 to 17 years.
- Analysis of probable and diagnosed long COVID outcomes post-vaccination.
Main Results:
- Vaccination rate was 67% in the cohort of 1,037,936 children.
- Adjusted VE against probable long COVID was 35.4% and against diagnosed long COVID was 41.7% within 12 months.
- VE was higher in adolescents (50.3%) than younger children (23.8%) and decreased significantly after 6 months.
Conclusions:
- Severe acute respiratory coronavirus 2 (SARS-CoV-2) vaccination demonstrates a moderate protective effect against long COVID in children.
- Vaccine effectiveness is more pronounced in adolescents and diminishes over time, particularly beyond 6 months.
- Further research, including prospective studies and analysis of electronic health records, is needed to elucidate the mechanisms of VE against long COVID.
Objectives:
Vaccination reduces the risk of acute coronavirus disease 2019 (COVID-19) in children, but it is less clear whether it protects against long COVID. We estimated vaccine effectiveness (VE) against long COVID in children aged 5 to 17 years.
Methods:
This retrospective cohort study used data from 17 health systems in the RECOVER PCORnet electronic health record program for visits after vaccine availability. We examined both probable (symptom-based) and diagnosed long COVID after vaccination.
Results:
The vaccination rate was 67% in the cohort of 1 037 936 children. The incidence of probable long COVID was 4.5% among patients with COVID-19, whereas diagnosed long COVID was 0.8%. Adjusted vaccine effectiveness within 12 months was 35.4% (95 CI 24.5-44.7) against probable long COVID and 41.7% (15.0-60.0) against diagnosed long COVID. VE was higher for adolescents (50.3% [36.6-61.0]) than children aged 5 to 11 (23.8% [4.9-39.0]). VE was higher at 6 months (61.4% [51.0-69.6]) but decreased to 10.6% (-26.8% to 37.0%) at 18-months.
Conclusions:
This large retrospective study shows moderate protective effect of severe acute respiratory coronavirus 2 vaccination against long COVID. The effect is stronger in adolescents, who have higher risk of long COVID, and wanes over time. Understanding VE mechanism against long COVID requires more study, including electronic health record sources and prospective data.
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