Estimating salivary carriage of severe acute respiratory syndrome coronavirus 2 in nonsymptomatic people and efficacy of mouthrinse in reducing viral load

Mouth rinses can reduce the SARS-CoV-2 viral load in saliva of both asymptomatic and symptomatic patients, according to a study published by The Journal of the American Dental Association.

Researchers recruited 201 asymptomatic, presymptomatic, postsymptomatic and symptomatic people and measured copy numbers of SARS-CoV-2 in unstimulated saliva. The authors also randomly assigned 41 symptomatic patients to use a mouth rinse containing saline, 1 percent hydrogen peroxide, 0.12 percent chlorhexidine, or 0.5 percent povidone-iodine for 60 seconds. The authors measured viral load 15 and 45 minutes after rinsing.

Salivary SARS-CoV-2 was found in 23 percent of asymptomatic, 60 percent of postsymptomatic, and 28 percent of presymptomatic participants. All four rinses reduced SARS-CoV-2 viral load in saliva, with a median reduction of 61 percent to 89 percent at 15 minutes after rinsing and 70 percent to 97 percent at 45 minutes. Reduction percent was significantly correlated with initial viral load.

Both frequency of detection and amount of viral load were lower in asymptomatic and presymptomatic participants than symptomatic and postsymptomatic participants.

"Mouth rinsing for 60 seconds can reduce the salivary loads of SARS-CoV-2 for 45 minutes," said Purnima Kumar, DDS, PhD, corresponding author and professor at Columbus-based Ohio State University College of Dentistry. "Therefore, there is wisdom in using preprocedural mouthwashes for all patients." 

Read the full study here.