Coronavirus disease (COVID-19) was declared a pandemic by the World Health Organization on March 11. This rapidly spreading disease is caused by the novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The infection has spread to more than 140 countries, including the United States. As of March 16, more than 170,400 people had tested positive for SARS-CoV-2 and more than 6,619 people have died across the globe.
The number of new COVID-19 cases appears to be decreasing in China, but the number of cases are rapidly increasing worldwide. Based on available data, primarily from China, children (aged 0-19 years) account for only about 2% of all cases. Despite the probable low virulence and incidence of infection in children, they could act as potential vectors and transmit infection to more vulnerable populations. As of March 16, approximately 3,823 cases and more than 67 deaths had been reported in the United States with few pediatric patients testing positive for the disease.
SARS-CoV2 transmission mainly occurs via respiratory route through close contact with infected individuals and through fomites. The incubation period ranges from 2-14 days with an average of about 5 days. Adult patients present with cough and fever, which may progress to lower respiratory tract symptoms, including shortness of breath. Approximately 10% of all patients develop severe disease and acute respiratory distress syndrome (ARDS), requiring mechanical ventilation.
COVID-19 carries a mortality rate of up to 3%, but has been significantly higher in the elderly population, and those with chronic health conditions. Available data so far shows that children are at lower risk and the severity of the disease has been milder compared to adults. The reasons for this are not clear at this time. As of March 16, there were no reported COVID-19 related deaths in children under age 9 years.
The pediatric population: Disease patterns and transmission
The epidemiology and spectrum of disease for COVID-19 is poorly understood in pediatrics because of the low number of reported pediatric cases and limited data available from these patients. Small numbers of reported cases in children has led some to believe that children are relatively immune to the infection by SARS-CoV-2. However, Oifang et al. found that children are equally as likely as adults to be infected.1
Liu et al. found that of 366 children admitted to a hospital in Wuhan with respiratory infections in January 2020, 1.6% (six patients) cases were positive for SARS-CoV-2.2 These six children were aged 1-7 years and had all been previously healthy; all six presented with cough and fever of 102.2° F or greater. Four of the children also had vomiting. Laboratory findings were notable for lymphopenia (six of six), leukopenia (four of six), and neutropenia (3/6) with mild to moderate elevation in C-reactive protein (6.8-58.8 mg/L). Five of six children had chest CT scans. One child’s CT scan showed “bilateral ground-glass opacities” (similar to what is reported in adults), three showed “bilateral patchy shadows,” and one was normal. One child (aged 3 years) was admitted to the ICU. All of the children were treated with supportive measures, empiric antibiotics, and antivirals (six of six received oseltamivir and four of six received ribavirin). All six children recovered completely and their median hospital stay was 7.5 days with a range of 5-13 days.
Xia et al. reviewed 20 children (aged 1 day to 14 years) admitted to a hospital in Wuhan during Jan. 23–Feb. 8.3 The study reported that fever and cough were the most common presenting symptoms (approximately 65%). Less common symptoms included rhinorrhea (15%), diarrhea (15%), vomiting (10%), and sore throat (5%). WBC count was normal in majority of children (70%) with leukopenia in 20% and leukocytosis in 10%. Lymphopenia was noted to be 35%. Elevated procalcitonin was noted in 80% of children, although the degree of elevation is unclear. In this study, 8 of 20 children were coinfected with other respiratory pathogens such as influenza, respiratory syncytial virus, mycoplasma, and cytomegalovirus. All children had chest CT scans. Ten of 20 children had bilateral pulmonary lesions, 6 of 20 had unilateral pulmonary lesions, 12 of 20 had ground-glass opacities and 10 of 20 had lung consolidations with halo signs.
Wei et al., retrospective chart review of nine infants admitted for COVID-19 found that all nine had at least one infected family member.4 This study reported that seven of nine were female infants, four of nine had fever, two had mild upper respiratory infection symptoms, and one had no symptoms. The study did report that two infants did not have any information available related to symptoms. None of the infants developed severe symptoms or required ICU admission.
The youngest patient to be diagnosed with COVID-19 was a newborn of less than 24 hours old from England, whose mother also tested positive for SARS-CoV-2. However, Chen et al. found no evidence of vertical transmission of the virus from infected pregnant women to their newborns.5
Although the risk of infection in children has been reported to be low, the infection has been shown to be particularly severe in adults with compromised immune systems and chronic health conditions. Thus immunocompromised children and those with chronic health conditions are thought to be at a higher risk for contracting the infection, with the probability for increased morbidity and mortality. Some of these risk groups include premature infants, young infants, immunocompromised children, and children with chronic health conditions like asthma, diabetes, and others. It is essential that caregivers, healthy siblings, and other family members are protected from contracting the infection in order to protect these vulnerable children. Given the high infectivity of SARS-CoV-2, the implications of infected children attending schools and daycares may be far reaching if there is delayed identification of the infection. For these reasons, it is important to closely monitor and promptly test children living with infected adults to prevent the spread. It may become necessary to close schools to mitigate transmission.
Schools and daycares should work with their local health departments and physicians in case of infected individuals in their community. In China, authorities closed schools and allowed students to receive virtual education from home, which may be a reasonable choice depending on resources.