Common Coronavirus Disease 2019 Upper Respiratory Tract Sampling Techniques in Children

Background: During COVID-19 pandemic, most studies have focused on sampling technique in adults. Considering the need to be aware of the effectiveness and evaluation of sampling methods in children, we have motivated a search for introducing and performing sampling techniques, especially upper respiratory tract sampling in children. We systematically reviewed the literature to understand the performance of different sampling methods in children in COVID-19. Methods: We systematically reviewed PubMed, Google Scholar, medRxiv, and bioRxiv (last retrieval August 1st, 2021) for comparative studies of deferent sampling techniques by using the search keywords including: children, pediatric sampling, nasopharyngeal, COVID-19, oropharyngeal, swabs, SARS, CoV2. 8 relevant manuscripts were sourced from a total of 4852 search results. Results: Nasopharyngeal (NP) swabs testing significantly had higher positivity rate over oropharyngeal swab in detecting SARS-CoV-2. Nasal swab has a low sensitivity in detecting SARSCoV-2 in children when referred to the nasopharyngeal aspiration (NPA), whereas its specificity is high. Therefore, NPA can be as the gold standard for detection of SARS-CoV-2. Conclusion: Saliva is not a useful for diagnosing COVID-19 in children. Negative nasopharyngeal and oropharyngeal swabs do not rule out COVID-19 and in patients with strong clinical suspicion, and Bronchoalveolar lavage (BAL) can be helpful.