Sampling methods and assays applied in SARS-CoV-2 exposure assessment

The SARS-CoV-2 exposure assessment is critical to implement control measures and guarantee the safety of patients and workers from different occupational environments. The aim of this review article was to identify methodologies applied for SARS-CoV-2 sampling and analyses in environmental samples in different occupational and indoor environments. This study reports the search of available data published between May 29th, 2020, and November 1st, 2020. The search strategy used allowed the identification of 48 papers that comply with selected inclusion and exclusion criteria. The most described indoor environment consisted of health care facilities. From all the analyzed studies, 34 sampled surfaces, 27 sampled air (impactors and impingers being the most used), and 9 sampled water. All studies were based on molecular detection by qPCR of viral RNA extracted from collected samples. SARS-CoV-2 was detected in 44 out of the 48 studies. The results suggest that the sampling approach should include both active and passive sampling methods in order to overcome each method's limitations. Concerning the assays used, although most studies were based on qPCR detection, the fact that the digital PCR technique allows SARS-CoV-2 detection at lower concentrations indicates that this should be the chosen method for future detection studies.