SARS-CoV-2 reinfection: a possible contributing factor to long COVID in children and adolescents

Following the end of the COVID-19 pandemic, attention shifted towards patients who developed sequelae, persistent symptoms, or relapsing or remitting symptoms of new conditions after a prior history of acute SARS-CoV-2 infection. The objective of the present study was to identify the prevalence, clinical characteristics, and potential associated factors of long COVID in children treated during the pandemic in a primary care unit.

A cross-sectional analytical study was conducted from January to December 2022. Children under 18 years of age and their parents were included in the study if they had been treated at the Mexican Social Security Institute. Two distinct manifestations of long COVID were considered: (a) "persistence", defined as continuous symptoms beginning in the acute phase and lasting for more than 3 months; and (b) "post-COVID conditions", defined as new or recurrent symptoms lasting for more than 3 months, appearing after the acute episode, and not associated with any active disease or infectious condition. An exploratory binary logistic regression analysis was performed to identify associated factors, using an odds ratio (OR) as the measure of association.

The study included 349 children and adolescents. The prevalence of long COVID was 11.8% (_95%CI 7.8%-17.5%). For "persistence", the most frequent symptoms were cough (50%) and rhinorrhea (15.4%); for "post-COVID conditions", the most common symptoms were myalgia (33.3%), asthenia and irritability (26.7% each), and constipation (20%). Multivariate analysis revealed that the associated factors for individuals aged over 8 years were a history of reinfection (OR 9.7, _95%CI 1.6-58) and BMI at the time of the survey (OR 1.1, _95%CI 1.0-1.2), while for those aged under 8 years, the associated factor was male sex (OR 4.7, _95%CI 1.3-17.3). It is important to emphasize that these results are the product of an exploratory analysis and aim to create and test new hypotheses.

For healthcare professionals, it is crucial to consider the possibility of long COVID, as this study indicated that approximately 12% of children and adolescents may be affected. Further research is necessary to better understand and manage long COVID in pediatric populations and to investigate the association between reinfections and their increased prevalence.