Worn Face Mask Testing to Diagnose SARS-CoV-2 Infection in Hemodialysis Patients

ABSTRACT

Background: Hemodialysis (HD) patients are at increased risk for COVID-19 infection, hospitalization, and mortality. Early COVID-19 diagnosis is thus critical to mitigate SARS-CoV-2 spread and improving patients' health outcomes. Generally, nasopharyngeal (NP) specimens are considered the most sensitive biological samples to diagnose SARS-CoV-2 infections. However, NP swabbing is considered uncomfortable by most patients, and it requires health professionals, thus impacting its cost-effectiveness. In a previous proof-of-principle study, we demonstrated that face masks worn by in-center HD patients can harbor SARS-CoV-2. In this Kidney-X funded study, we determined efficiency of face mask testing by comparing results to saliva specimen collected from same individuals. Method(s) Disposable 3-layer masks were provided to each subject at the time of entering the dialysis center. Masks were collected 4 hours after worn. Saliva was collected using Salivette kit at the time of mask collection. RT-PCR based testing were performed using Thermo Fisher COVID-19 Combo Kit (A47814). Result(s) We collected 179 pairs of saliva/masks, 114 from 42 dialysis staff and patients without recent COVID-19 infection (control group), and 65 from 30 HD patients with COVID-19, diagnosed by NP RT-PCR (COVID-19 group). Patients provided 1 to 7 sample pairs on average 11+/-8 days (0 to 36) after COVID-19 diagnosis. Thirty-one of the 65 sample pairs were SARS-CoV-2 positive either in the saliva or the mask samples (26 positive saliva;20 positive masks). Saliva and mask testing sensitivities were 84% and 65% with a mean cycle threshold (CT) of 31.8 and 32.2, respectively. Fifteen pairs tested positive for both worn masks and saliva. Mask and saliva CT values did not differ significantly. Of note, in 5 sample pairs saliva tested negative while masks tested positive. In the control group, all 114 saliva samples tested negative;one mask tested weakly positive, resulting in saliva and mask testing specificities of 100% and 99%, respectively. S gene dropout was observed in all positive samples, indicating Omicron BA.1 infection. Conclusion(s) While the sensitivity of mask testing is less compared to saliva testing, its operational ease, lack of patient discomfort, seamless repeatability, and lower costs make it a viable option for SARS-CoV-2 screening.