Lack of Fever and Exposure to SARS-CoV-2 Serves as a 'Diagnostic Razor' to Reasonably Exclude COVID-19 in Most Children with Suspected Infection

Objective: The objective of this study is to test how certain signs and symptoms related to Covid-19 in children predict the positivity or negativity of the SARS-CoV-2 nasopharyngeal swab in children, to better prioritize the population at risk and save the human and material resources of overloaded paediatric emergency departments during the current pandemic.  Study Design: We review the data of 2940 individuals aged 18 years or less who were tested for SARS-CoV-2 for a clinical suspicion of infection or for hospital infection-prevention protocol. We performed a statistical analysis on the former, including the sensibility, specificity, positive and negative predictive values of different combination of signs and symptoms against the positive or negative result of the SARS-CoV-2 test. Of the latter, we excluded 241 subjects and considered the 4 positive subjects for a separate description.  Results: Fever and respiratory symptoms were the most reported symptoms in all patients. In our sample, 96.2% of the subjects tested negative, and 3.8% tested positive to the SARS-CoV-2 naso-pharyngeal swab. Most positive children had a prior exposure to a SARS-CoV-2 infected subjects (59.2%). Headache was the single most reported symptom by positive subjects (8.7%), when compared to negative ones (2.3%). Negative predictive values higher than 90% were obtained for all negative combinations of fever, respiratory symptoms and/or exposure to SARS-CoV-2. Interestingly, 99.3% of patients without fever nor exposure to the virus proved negative to the SARS-CoV-2 test.  Conclusion: Our study suggests that a child without fever or contact with infected subjects, even when presenting with mild respiratory symptoms, in most cases will prove negative to SARS-CoV-2 testing. If this were to be confirmed by further studies, many resources would be spared, leading to an improved care of both Covid-19 and not Covid-19 affected children. Funding Statement: None to declare. Declaration of Interests: None to declare. Ethics Approval Statement: The study was approved by the Ethics Committee of Bambino Gesu Children’s Hospital, according to the Declaration of Helsinki (as revised in Seoul, Korea, October 2008). The number protocol was 2336_OPBG_2020.