Within a 12-month time frame, adjusted vaccine effectiveness against diagnosed long and probable long COVID was 41.7% and 35.4%, respectively.
COVID-19 vaccination showed a moderate protective effect against long COVID in children, new research published in the journal Pediatrics found.1 The study also found the effect was stronger in adolescents, who are typically at a higher risk for the condition.
Long COVID impacts roughly 1 in 5 adults and includes symptoms such as muscle pain, memory loss, shortness of breath, and difficulty concentrating. While not as much is known about long COVID in children and adolescents, research has found that around 4% of children experience lingering symptoms.2 Vaccination is known to have a positive impact on long COVID in adults, but there has so far been little data in children and adolescents.
“To date, no studies have assessed clinical data for large, diverse groups of children to address this important question,” Hanieh Razzaghi, lead author on the study, said in a release.3 “Using clinical data from across health care networks allowed us to have a large enough sample of patients to identify rare effects of the virus and its impact on children.”
Investigators from the Children’s Hospital of Philadelphia, in collaboration with 17 other health systems throughout the United States, conducted a retrospective cohort study to estimate vaccine effectiveness against long COVID in children ages 5 to 17 years. Data was gathered from the RECOVER PCORnet electronic health record program, a collection of data aiming to generate evidence around long COVID in adults and children.
The study cohort included 1037936 children and adolescents, with 480489 in the 5 to 11 year old group and 719519 in the 12 to 17 year old group. The main study outcomes were diagnosed or probable long COVID. Diagnosed long COVID was defined as 2 or more visits with diagnosis codes specific for long COVID, while probable long COVID was defined as 1 diagnosis code.
The vaccination rate amongst the entire cohort was 56%. Investigators found the incidence of diagnosed long COVID among patients with COVID-19 was 0.7% and probable long COVID was 4.5%. Within a 12-month time frame, adjusted vaccine effectiveness against diagnosed long and probable long COVID was 41.7% and 35.4%, respectively.
Vaccine effectiveness was demonstrated to be 61.4% at 6 months, but decreased to 10.6% at 18 months. Additionally, vaccine effectiveness was higher among adolescents at 50.3% compared to children at 23.8%.
“This study provides us with important data showing the protective effects of the vaccine against long-haul COVID and suggests that this protection is mostly from preventing visible infections,” Charles Bailey, senior author on the study, said in a release.3 “We hope this means that as vaccines are improved to be more effective against current strains of SARS-CoV-2, their protection against long COVID will get better, too.”