OBJECTIVE

Vaccination reduces the risk of acute 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 5-17 years.

METHODS

This retrospective cohort study used data from 17 health systems in the RECOVER PCORnet electronic health record (EHR) Program for visits after vaccine availability. Conditional logistic regression was used to estimate VE against long COVID with matching on age group (5-11, 12-17) and time period and adjustment for sex, ethnicity, health system, comorbidity burden, and pre-exposure health care utilization. We examined both probable (symptom-based) and diagnosed long COVID in the year following vaccination.

RESULTS

The vaccination rate was 56% in the cohort of 1,037,936 children. The incidence of probable long COVID was 4.5% among patients with COVID-19, while diagnosed long COVID was 0.7%. Adjusted vaccine effectiveness within 12 months was 35.4% (95 CI 24.5 – 44.5) against probable long COVID and 41.7% (15.0 – 60.0) against diagnosed long COVID. VE was higher for adolescents 50.3% [36.3 – 61.0]) than children aged 5-11 (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 – 37.0%) at 18-months.

DISCUSSION

This large retrospective study shows a moderate protective effect of SARS-CoV-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 EHR sources and prospective data.

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Competing Interests

CONFLICT OF INTEREST DISCLOSURES: Dr. Mollie Cummins is employed by Doxy.me Inc., a commercial telemedicine platform provider. Dr. Benjamin Horne is a member of the advisory boards of Opsis Health and Lab Me Analytics, and a consultant to Pfizer (regarding clinical risk scores; funds paid to Intermountain). Dr. Susanna Naggie reports research grants from Gilead Sciences and AbbVie, scientific advisor/stock options from Vir Biotechnologies, consulting with no financial payment from Pardes Biosciences and Silverback Therapeutics, DSMB fees from Personal Health Insights, Inc, event adjudication committee fees from BMS/PRA outside the submitted work. Dr. Mishkin receives Grant support from Pfizer paid directly to Institution Advisory Board for Takeda. Dr. Jhaveri is a consultant for AstraZeneca, Seqirus, Dynavax, receives an editorial stipend from Elsevier and Pediatric Infectious Diseases Society. Dr. Rao reports prior grant support from GSK and Biofire and is a consultant for Sequiris. The remaining authors have no disclosures.