Subgingival Plaque as a Potential Reservoir for SARS-CoV-2 Virus in Patients Recovered from COVID-19 Infection: A Cross-sectional Study

Background: Subgingival plaque biofilm is a potential harboring site for bacteria and viruses, serving as a source of entry into the bloodstream. The presence of Severe Acute Respiratory Syndrome Coronavirus 2 RNA (SARS-CoV-2 RNA) in subgingival plaque could be a possible source for cross infection due to aerosol contamination during dental procedures.

Objective: The objective of this study was to investigate the presence of SARS-CoV-2 RNA in the subgingival plaque biofilm of patients who recovered from COVID-19 infection.

Methodology: Ten subjects visiting the Outpatient clinic with a previous history of COVID-19 infection were recruited for this cross-sectional study. Subgingival plaque sample was collected from all four quadrants using a sterile curette. Nasopharyngeal and oropharyngeal swabs were taken from all the subjects. Reverse transcriptase real-time qualitative polymerase chain reaction (RT-PCR) was used to determine the presence of SARS-CoV-2 RNA using BAG SARS-CoV-2 RT-PCR kit targeting E gene, RdRp gene, and internal control.

Results: Ten participants (seven females and three males) with a previous history of COVID-19 infection were included in the study. Six participants previously presented with mild COVID-19 infection (uncomplicated upper respiratory tract infection, mild fever, cough, sore throat, nasal congestion, malaise, headache, without evidence of breathlessness or hypoxia), and four participants previously presented with moderate COVID-19 infection (dyspnea and or hypoxia, fever, cough, SpO2 90%−94% on room air, respiratory rate more or equal to 24 per minute) according to clinical management protocol for COVID-19, Government of India. The nasopharyngeal, oropharyngeal, and subgingival plaque samples tested negative for SARS-CoV-2 RNA.

Conclusion: The absence of the SARS-CoV-2 virus in the subgingival plaque sample of patients recovered from COVID-19 infection suggests that dental plaque could not be a potential reservoir of the virus. However, clinicians should take at most precautions while treating the patients recovered from COVID-19 infection and should anticipate a change in subgingival environment leading to alteration in periodontal disease progression.