COVID-19 in Children and the Dynamics of Infection in Families.

Abstract

Since the onset of coronavirus disease (COVID-19) pandemic, children have been less affected than adults in terms of severity1–3 and frequency, accounting for <2% of the cases.2–5 Unlike with other viral respiratory infections, children do not seem to be a major vector of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission, with most pediatric cases described inside familial clusters6 and no documentation of child-to-child or child-to-adult transmission.7,8 The aim of this work was to describe the clinical presentation of the first 40 pediatric cases of COVID-19 in our city and the dynamics of their familial clusters.From March 10 to April 10, 2020, all patients <16 years old with SARS-CoV-2 infection were identified by means of the Geneva University Hospital’s surveillance network (Switzerland). The network notifies the institution’s pediatric infectious diseases specialists about results of nasopharyngeal specimens tested for SARS-CoV-2 by reverse-transcription polymerase chain reaction. This study was approved by the Regional Ethics Committee. After informed oral parental consent and its documentation in the medical charts, chart reviews were used to retrieve clinical data, and parents were called for patients and household contacts (HHCs) follow-up. HHCs were considered suspect if they had fever or acute respiratory symptoms, as per the Swiss Federal Office for Public Health’s case definition9 (Supplemental Information).Categorical data were compared using the χ2 test, with P values <.05 considered significant. Statistics were performed using SPSS version 23.0 (IBM SPSS Statistics, IBM Corporation).Among a total of 4310 patients with SARS-CoV-2, 40 were <16 years old (0.9%). One patient for which telephone follow-up was not possible was excluded because of the inability to evaluate clinical evolution and HHC symptoms. The median follow-up of the households was 18 days (interquartile range [IQR]: 14–28).Demographics, clinical presentation, and diagnosis of the study children are detailed in Table 1. Of note, 29 (74%) patients were previously healthy; the most frequently reported comorbidities were asthma (10%), diabetes (8%), obesity (5%), premature birth (5%), and hypertension (3%). Seven patients (18%) were hospitalized to the ward, for a median duration of 3 days (IQR: 2–4); reasons for admission were surveillance for nonhypoxemic viral pneumonia (n = 2), fever without source (n = 2), apparent life-threatening event (n = 1), and sepsis-like event (n = 1); 1 paucisymptomatic child admitted because both parents had severe COVID-19 (n = 1). No patient required ICU admission or SARS-CoV-2–specific therapies. The others 32 patients were managed as outpatients. All patients had a complete resolution of symptoms by day 7 after diagnosis.Familial cluster evaluation revealed a t number of 4 household members per family (IQR: 3–4). Among the 111 HHCs of study children, mothers predominated (n = 39), followed by fathers (n = 32), pediatric siblings (n = 23), adult siblings (n = 8), and grandparents (n = 7) (Fig 1). Adult HHCs were suspected or confirmed with COVID-19 before the study child in 79% (31/39) of cases. In only 8% (3/39) of households did the study child develop symptoms before any other HHC (Fig 1). Interestingly, 85% (75/88) of adult HHCs developed symptoms at some point, compared with 43% (10/23) of pediatric HHCs (P < .001). Also, 92% (36/39) of mothers developed symptoms, compared with 75% (24/32) of fathers (P = .04).Most children in our study had mild or atypical presentations: headache and nasal discharge were described in more than half of cases, and anosmia and abdominal symptoms were described in <20%, which is more frequent than previously described.2 Some of these symptoms might be underreported because younger children may not be able to describe them.In 79% of households, ≥1 adult family member was suspected or confirmed for COVID-19 before symptom onset in the study child, confirming that children are infected mainly inside familial clusters.6 Surprisingly, in 33% of households, symptomatic HHCs tested negative despite belonging to a familial cluster with confirmed SARS-CoV-2 cases, suggesting an underreporting of cases. In only 8% of households did a child develop symptoms before any other HHC, which is in line with previous data in which it is shown that children are index cases in <10% of SARS-CoV-2 familial clusters10; however, with our study design, we cannot confirm that child-to-adult transmission occurred.This study has some limitations. The study sample likely does not represent the total number of pediatric SARS-CoV-2 cases during this time period. Indeed, patients with milder or atypical presentation might not have sought medical attention. Moreover, the recall of symptom onset among HHCs might be inaccurate, although this seems for once less likely because of the confinement measures and anxiety in the community.The results of this study are important because of the extensive HHC tracing and the almost absence of loss to follow-up. Extended diagnostic screening of suspected cases and thorough contact tracing are needed to better understand the dynamics of transmission within households.