Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) viral positivity and their burden in saliva of asymptomatic carriers–a systematic review and meta-analysis

Aims: The coronavirus disease 2019 (COVID-19) due to the severe acute respiratory syndrome coronavirus-2 (SARS‐CoV‐2) can present either as an asymptomatic carrier state or an acute respiratory disease, with or without severe pneumonia. The asymptomatic carriers are a challenge for the dental profession as the infection could be transmitted via virus-laden, and saliva in dental settings through aerosol-generating procedures (AGPSs). The aim of this review was to perform a systematic review of SARS‐CoV‐2 in the saliva of asymptomatic individuals. Materials and methods: PubMed, Google scholar, and MedRxiv databases were searched between and a systematic review and meta-analysis of the available data were performed to assess the viral burden in the saliva of asymptomatic carriers of SARS-CoV-2. All investigators of the included studies used qRT-PCR to detect SARS-CoV-2 and yield quantitative data (the Ct values) appertaining to the viral load. Results: A total of 322 records in the English literature were identified, and eight studies with 2642 SARS‐CoV‐2-positive and asymptomatic individuals were included in the final analysis. Of these, 16.7% (95% CI: 11–23%) yielded SARS-CoV-2-positive saliva samples in comparison to 13.1% (95% CI: 12–17%) of the respiratory specimens (nasopharyngeal or nose-throat swabs). Conclusion: As approximately 1 in 5 to 1 in 10 asymptomatic individuals harbour SARS-CoV-2 in either saliva or respiratory secretions, our results highlight the need for continued vigilance and the critical importance of maintaining strict, additional infection control regimens for the foreseeable future to mitigate the potential risks of COVID-19 transmission in dentistry.