Saliva‐direct approach in the detection of SARS‐CoV‐2 in the lower‐risk population in Colombia

INTRODUCTION The ongoing coronavirus disease 2019 (COVID-19) pandemic requires population-wide surveillance testing to test for the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. 1 Quantitative reverse-transcription polymerase chain reaction (RT-qPCR) using nasopharyngeal samples has been used as the gold-standard of detection, but it requires trained personnel, sterilized swabs, RNA extraction, and causes discomfort in the patient being tested. 2 As alternative upper respiratory tract samples such as saliva have proven to be reproducible and sensitive enough in detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and are part of the recommended options for testing according to the US Food and Drug Administration which granted accelerated emergency use authorization to an open source protocol known as Saliva-Direct. 3 Among the advantages of this approach saliva can be self-collected, it is stable at different temperatures and does not require an RNA extraction step. 4 Colombia with a population of around 48 million and 6,308,087 positive cases of COVID-19, as of October 12, 2022 5 highlights the need for surveillance testing. [...]to 8-strip 200 μl PCR tubes we added 6.25 μl of a 20 mg/ml stock of Proteinase K (New England Biolabs P8107S) and 4 μl of RNAsecure (Thermo Fisher AM7006). The inner region is defined as the region bounded by all the curves corresponding to the points of the bag. [...]50% of the curves are in the interior region. In Colombia the age group 20–29 and 30–39 reported the most cases in the city of Bogota. 14 According to the literature the younger population tend to present a lesser mortality and lower incidence of symptomatic cases, but it is also the population with the most social interactions playing an important role in the spread of the virus. 15–18 This highlights the need for surveillance in this population as already reported in previous studies where the presence of the virus was reported in saliva samples of asymptomatic carriers. 19 CONCLUSION We conclude that the Saliva-Direct approach is appropriate for surveillance of the SARS-CoV-2 virus in the low-risk population in Colombia if the threshold on cycle count for a positive is established in the testing lab using a functional analysis approach.