SARS-CoV-2 Infections in Icelandic Children: Close Follow-up of All Confirmed Cases in a Nationwide Study

Abstract

Introduction: Children are less likely to acquire SARS-CoV-2 infections than adults and when infected, usually have milder disease. True infection and complication rates are, however, difficult to ascertain. In Iceland, a strict test, trace and isolate policy was maintained from the start of the pandemic and offers more accurate information of the number of truly infected children in a nationwide study.

Material and methods: All children with positive PCR for SARS-CoV-2 infections from February 28, 2020 to August 31, 2021 were followed up through telephone consultations for at least 14 days and their symptoms were registered. Symptom severity and duration were categorized based on age groups and the source of infection was registered.

Results: A total of 1749 children were infected with SARS-CoV-2 in 3 waves of infections. All waves had similar disease severity whereas the incidence was 5-fold higher in the third wave (3.5 vs. 0.73/1000 children/month). No children had severe symptoms, 81 (4.6%) had moderate symptoms, 1287 (73.9%) had mild and 374 (21.5%) were asymptomatic. Symptoms from upper (n = 839, 48%) and lower respiratory tract (n = 744, 43%) were most common. Median duration of symptoms was 5 days and adolescents had a higher risk of prolonged duration [OR:1.84 (1.39-2.43)]. Nineteen (1.1%) children needed medical attention, but no child was hospitalized. The source of infection was a household member in 65% of cases.

Discussion: During the first 3 waves of the pandemic, SARS-CoV-2 infections in Icelandic children were mild and none were hospitalized. The most common symptoms were respiratory symptoms followed by fever, headache and tiredness. This study helps shed light on true complication rates of children with confirmed SARS-CoV-2 infection.

FIGURE 1.

Number of SARS-CoV-2 infections in Icelandic children from March 2020–August 2021 Three waves of COVID-19 disease in children in Iceland from March 2020–August 2021. The third wave was dominated by the delta variant of SARS-CoV-2. The median age of children infected with SARS-CoV-2 was 12 years in the first wave and 10 years in both subsequent waves. The mean age-standardized incidence per 1000 children/month was 0.73 during the first wave, 0.73 in the second wave and 3.5/1000 children/month during the third wave.

FIGURE 2.

Registered symptoms of SARS-CoV-2 infections in 1742 Icelandic children until the end of August 2021. Upper respiratory symptoms were: sore throat and runny nose. Lower respiratory symptoms: cough, shortness of breath. Abdominal symptoms: diarrhea, vomiting, abdominal pain. Other: light sensitivity, ear pain, dizziness, chills, irritability.

FIGURE 3.

Symptom severity of SARS-CoV-2 infection in Icelandic children. Classification of severity of SARS-CoV-2 infection in 1742 Icelandic children. No child had severe symptoms.