Investigation of Clinical Manifestations and Laboratory Findings of COVID-19 During National Peaks of Alpha, Beta, Delta, and Omicron in the Pediatric Emergency Department of Mofid Children's Hospital, Tehran, Iran

Background: The global spread of the coronavirus since 2019 has caused significant concern. Objectives: In this study, we aimed to investigate the clinical manifestations and laboratory findings of children infected with the alpha, beta, delta, and omicron strains. Methods: We included all patients who were referred to Mofid Children's Hospital during the peak of the alpha strain in November 2020, the beta strain in April 2021, the delta strain in August 2021, and the omicron strain in February 2022, corresponding to the national peaks of four SARS-CoV-2 variants of concern (VOC). All patients had a positive nasopharyngeal PCR test and were admitted to the emergency ward. We analyzed the collected data using SPSS software. Results: A total of 649 patients were included in this survey, of whom 58.1% were male. The most and least frequent clinical manifestations were fever and skin presentation, respectively. The mean white blood cell count (WBC) was 8423.9 ± 5427.3. The mean values for C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were 30.14 ± 20.07 and 38 ± 22.6, respectively. There was no significant association between coronavirus type, age, and gender. Gastroenteritis, urinary tract infection, and croup showed a statistically significant positive correlation with delta, beta, and omicron (P-values of < 0.003, 0.000, and 0.000, respectively). Cough was more frequent in patients infected with alpha and beta subtypes, while lymphocyte counts were elevated in patients suffering from delta, omicron, and alpha. C-reactive protein and ESR levels were significantly increased in patients with delta infection, and in patients with omicron infection, CRP levels were significantly elevated. Conclusions: Our study revealed that the different strains of COVID-19, corresponding to the World Health Organization (WHO) peak of VOCs, can cause variable clinical symptoms in children. These findings could be helpful in the diagnosis of COVID-19.