Vaccine Effectiveness Against Long COVID in Children

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.