Many individuals infected SARS-COV2 never develop significant symptoms. With 24 million Americans already infected and highly transmissible variants rapidly emerging, it is highly probable that post- and pre-symptomatic individuals will form a significant fraction of those seeking dental care. Salivary carriage rates in these populations are not known. Moreover, although preventing transmission is critical for controlling spread, the efficacy of mouthrinses in reducing oral viral load is poorly studied.background

201 asymptomatic, pre-symptomatic, post-symptomatic and symptomatic individuals were recruited and copy numbers of SARS-CoV2 measured in unstimulated saliva using real-time reverse transcriptase quantitative PCR. 41 symptomatic individuals were subsequently inducted into a randomized, triple-blinded study and instructed to rinse with saline, 1% hydrogen peroxide, 0.12% chlorhexidine or 0.5% povidone-iodine for sixty seconds. Viral load was measured 15- and 45-minutes post-rinsing.

Salivary SARS-CoV2 was detected in 23% of asymptomatic, 60% of post-symptomatic and 28% of pre-symptomatic individuals. Neither carriage rate nor viral load correlated with COVID symptomatology, age, gender or ethnicity. All four mouthrinses decreased viral load by 61-89% at 15 minutes, and by 70-97% at 45 minutes. The extent of reduction correlated significantly with initial viral load.results

Non-symptomatic individuals can pose a risk for viral transmission, and mouthrinses are simple and efficacious means of reducing this risk, especially when the load is <104 copies/ml.conclusion

At a time when resources are stretched, our findings contribute to evidence-based selection of personal protection equipment and simple infection control practices to reduce contagion at source.