Long COVID in children and adolescents: a historical cohort study with a population-based control group from Iran

After recovering from the acute phase of COVID-19, some of the infected children manifest long COVID symptoms. The present study aims to identify long COVID symptoms in children and adolescents admitted to hospitals in Bushehr, Iran, during 2021 to 2023, and compare them with the non-affected group.

This historical cohort study with a population-based control group was conducted on 141 children and adolescents with COVID-19 hospitalized in Bushehr city hospitals and 141 non-affected peers. Out of 10 comprehensive health service centers in Bushehr city, 5 centers were selected by random sampling and the non-Covid-19 group was chosen from them (matched by gender and age with the affected group). The data were collected using the data recorded in the patients' records, conducting telephone interviews and completing the prevalent long COVID symptom form. Data were analyzed using SPSS version 18. Descriptive statistics, Chi-square/Fisher's exact tests, and stepwise logistic regression were used. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated, with p < 0.05 as the significance level.

The mean age of the hospitalized children with COVID-19 was 79 ± 5.24 months old, 57.4% of whom were boys. Also, 46 individuals of the COVID-19 group (32.6%) manifested long COVID symptoms. The most prevalent symptoms included fatigue (54.3%), impaired attention or concentration (41.3%) and depression or anxiety symptoms (34.7%). Among the hospitalized children experiencing long-term COVID symptoms, 65.2% exhibited moderate disease severity. A significant relationship was identified between disease severity and muscle and joint pain (P = 0.025), as well as between the length of hospital stay and cough (P = 0.022), weight loss (P = 0.047), and symptoms of depression or anxiety (P = 0.008). Older age [(6-11 y; OR = 3.18, CI = 1.03-9.88); (12 ≥ y; OR = 4.57, CI = 1.40-14.96)] and having history of smoking or being exposed to secondhand smoke (OR = 12.45, CI = 3.14-49.36) were considered as risk factors for long COVID.

The variables of age and history of exposure to tobacco smoke exhibited a significant independent relationship with the occurrence of long-term COVID symptoms in children hospitalized due to COVID-19. Specifically, as age increases and the history of tobacco smoke exposure rises, the likelihood of experiencing long-term COVID symptoms also increases.