SARS-CoV-2 positivity in asymptomatic-screened dental patients

Abstract

Enhanced community surveillance is a key pillar of the public health response to COVID-19. Asymptomatic carriage of SARS-CoV-2 is a potentially significant source of transmission, yet remains relatively poorly understood. Disruption of dental services continues with significantly reduced capacity. Ongoing precautions include pre- and/or at appointment COVID-19 symptom screening and use of enhanced personal protective equipment (PPE). This study aimed to investigate SARS-CoV-2 infection in dental patients to inform community surveillance and improve understanding of risks in the dental setting. Thirty-one dental care centres across Scotland invited asymptomatic screened patients over 5-years-old to participate. Following verbal consent and completion of sociodemographic and symptom history questionnaire, trained dental teams took a combined oropharyngeal and nasal swab sample using standardised VTM-containing testkits. Samples were processed by the Lighthouse Lab and patients informed of their results by SMS/e-mail with appropriate self-isolation guidance in the event of a positive test. Over a 13-week period (from 3August to 31October2020) n=4,032 patients, largely representative of the population, were tested. Of these n=22 (0.5%; 95%CI 0.5%, 0.8%) tested positive for SARS-CoV-2. The positivity rate increased over the period, commensurate with uptick in community prevalence identified across all national testing monitoring data streams. All positive cases were successfully followed up by the national contact tracing program. To the best of our knowledge this is the first report of a COVID-19 testing survey in asymptomatic-screened patients presenting in a dental setting. The positivity rate in this patient group reflects the underlying prevalence in community at the time. These data are a salient reminder, particularly when community infection levels are rising, of the importance of appropriate ongoing Infection Prevention Control and PPE vigilance, which is relevant as healthcare team fatigue increases as the pandemic continues. Dental settings are a valuable location for public health surveillance.

Risk of SARS-CoV-2 transmission following exposure during dental treatment – A national cohort study

“…Similar to this, we found in our study that the exposure rate to asymptomatic/presymptomatic SARS-CoV-2 positive patients in dental clinics from May to October 2020 grew with the increase of infection level in the population [13] .…”

“…Asymptomatic / presymptomatic patients and DSMs infected by SARS-CoV-2 are potential sources of transmission in dental clinics. A recent study conducted in 2020 amongst 31 dental care centers in Scotland, found that the positivity rate among asymptomatic screened dental patients was in proportion to community prevalence and reflected the underlying prevalence at that time [13] .…”

Conference Outbreak March 2020 Incident Management Team report

“…In accordance with the guidance in place at the time of the outbreak, contacts were only tested if they were/became symptomatic. We now know that some infected individuals will present asymptomatically or with mild nontypical COVID-19 symptoms (8)(9)(10)(11). It is possible that asymptomatic cases among conference delegates or close contacts of primary cases may not have been detected as a result of the testing policy in place at the time of the outbreak.…”

Is saliva collected passively without forceful coughing sensitive to detect SARS-CoV-2 in ambulatory cases? A systematic review

“…The range is from 0.6% in the population referred to oral health cancer centers to 2.3 % in pediatric dental clinics. 6,7 Palla B, et al reported a higher number of positivity in asymptomatic patients attending the emergency department, half of whom had visited a dentist within seven days from their visit. 8 Due to the relatively high number of the positivity rate in asymptomatic cases, and the fact that 17.9% to 33.3% of infected patients will remain asymptomatic during the disease (especially in cases of delta variant), the importance of universal precautions and the significance of accessing a rapid screening and diagnostic test, which can be applicable to diagnose asymptomatic patients, especially in the dental setting, should be emphasized.…”