Hunan province is adjacent to Hubei province (Wuhan as the capital city), and as of 24:00 on June 30th, 2020, a total of 1,019 confirmed cases had been reported in Hunan province. The government authority has taken unprecedented and effective effort to reduce the risk of transmission. Early diagnosis, early isolation and early management all contributed to reducing transmission and mortality in Hunan.
Person-to-person transmission and Cluster are important epidemic features of this outbreak, and close family contact is the main way of SARS-CoV-2 infection in children. Of the 16 imported cases, 15 children had a clear history of exposure in Wuhan, one child had cruise trip exposure. Of the 48 cases in our study, 46 (96%) children had been exposed to confirmed adult patients and the other two children, who had been living in Wuhan, were imported cases. Compared to adults, children had atypical symptoms or were asymptomatic. In our study, 23% children were asymptomatic, indicating that the absence of clinical symptoms cannot rule out the diagnosis of infection. That's probably the reason why there were so few reported cases of COVID-19 in children and some asymptomatic pediatric patients were easily missed. Therefore, a detailed investigation of history of exposure to SARS-CoV-2 is particularly important for children. In our study, there was no significant difference in incidence of SARS-CoV-2 infection between male and female. 96% children in our study were predominantly asymptomatic, mild or moderate cases, with only 2 children who had severe disease, a 2-year old and a 4-year old. The age of the first critical pediatric patient of COVID-19 reported in China was one year old 11. Although the incidence of severe and critical illness of SARS-CoV-2 infection in children is low, it seemed that the younger the age, the higher the incidence of severe and critical cases might be. This may be related to the fact that organ functions are not fully developed and complications are likely to occur at a younger age.
Most children of SARS-CoV-2 infection in our study had mainly upper respiratory tract symptoms, such as fever, cough, fatigue, headache, nasal obstruction and runny nose. 46% children had progression to lower respiratory tract infection, which mainly occurred in 4-10 years group and 11-17 years group. 13% children in our research had gastrointestinal symptoms as vomiting and diarrhea, mainly in less than 3 years group and 4-10 years group, it showed a statistically significant difference. Gastrointestinal symptoms can be the only clinical manifestation in children, as shown in one child in this study, who presented with diarrhea as the only symptom in the disease course. Therefore, attention should be paid to some children without significant respiratory symptoms. SARS-CoV-2 is rarely reported to involve the nervous system. In this study, a 2-year old girl without any underlying disease developed convulsions in the early stages of SARS-CoV-2 infection, which was accompanied by high fever (>39℃) and didn’t recur after fever disappeared. Although the child developed a severe case with typical ground glass opacity in both lungs, she did not show any neurological abnormalities. Therefore, we considered it was a febrile convulsion and was unrelated to SARS-CoV-2 infection.
Lymphocytopenia was common after the onset of SARS-CoV-2 infection in adults, but it was rare in children. In the initial routine blood tests of this group, there were only 5 cases with lymphocytopenia, three cases in the 4-10 years group and two cases in the 11-17 years group. Thus, for children, especially young children, lymphocytopenia lacks the sensitivity to an early diagnosis for the SARS-CoV-2 infection. On the whole, other laboratory findings in children with SARS-CoV-2 infection showed no significant specificity and sensitivity and could not provide strong evidence for the diagnosis but could be used as a reference indicator to exclude other diseases. CRP is one of the indicators to assess inflammation, and an elevated CRP was present in 60.7% of COVID-19 adult patients, especially in severe patients 2. In our study, only 3 children (6%) had elevated CRP, and two of the children were severe and had elevated procalcitonin. It is likely that patients with severe COVID-19 are more susceptible to secondary bacterial infection than patients with mild disease.
Our study showed some common CT imaging features in patients infected by SARS-CoV-2, including ground-glass opacity of bilateral lobular and subsegmental areas of consolidation, or mixture, without pleural effusion (white lung appearance). Although the abnormal manifestations of chest CT in some children were typical, they still need to be differentiated from other viral pneumonitis. Therefore, pediatricians should carefully verify the findings according to epidemiological history, clinical manifestations, viral nucleic acid detection and CT images, in order to improve the diagnostic accuracy in children.
At present, there is no specific drug for COVID-19. Based on “Diagnosis and prevention of 2019 novel coronavirus infection in children (trial version 1)”, the use of lopinavir/ritonavir (LPV/RTV) or ribavirin and interferon were recommended. Due to the difference in treatment regimens, dosages and combinations of antiviral drugs used different hospitals in this study group, it was difficult to determine the efficacy of antiviral drugs. The main treatment is mainly symptomatic and supportive care. If a child has a combined secondary bacterial infection, appropriate antibiotics may be used. It is highly recommended that appropriate antimicrobial agents should be selected after a full microbiological investigation, and timely adjustment should be made according to the curative effect and drug sensitivity test results, avoiding blind or inappropriate use of antibiotics. In reference to adult treatment experience in Wuhan city, routine use of corticosteroids should be avoided, and only reserved for severe cases with persistent high fever, CRP≥30 mg/L, serum ferritin≥1 000 μg/L or diffuse lesions in both lungs 3. The efficacy of IVIG for COVID-19 pneumonia is limited in adult patients. In this study, after IVIG treatment, the pulmonary lesions of the two severe cases were all resolved. Whether the effect of IVIG in children is greater than that in adults still needs more data to prove.
In this study, due to the limited number of cases and short study time, we did not collect all pediatric cases in Hunan province. We may not have a comprehensive understanding of the clinical characteristics and imaging manifestations of pediatric patients, so a future study with larger sample size from multiple centers is needed.
In conclusion, the epidemiological characteristics of 48 children with COVID-19 in Hunan province in this study were mainly clustered cases. Most children with SARS CoV-2 infection in Hunan province were asymptomatic, mild or moderate. Severe cases are rare. The younger the patients, the less obvious their symptoms may be. Epidemiological history, nucleic acid test and chest imaging were important tools for the diagnosis of COVID-19 in children.