Prediction of Potential Respiratory Tract Infection from SARS-CoV-2 Through Hand-to-face Contact Transmission.

OBJECTIVE: The Ministry of Health of China reported a cluster of severe pneumonia cases of unknown etiology in Wuhan city, the cause of which was later identified as a novel coronavirus. However, the risk of infection through indirect transmission routes remains unclear. METHODS: A mathematical modeling approach was used to estimate the risk of infection through hand-to-face contact. The probability of infection for various routes of transmission through face-touching behavior was then calculated. RESULTS: The probabilities of infection through hand-to-mouth transmission from nonporous and porous environments had log-normal (LN) distributions with geometric means (GMs) of 0.0116 and 0.0002, geometric deviations (GDs) of 2.9822 and 3.5560, and medians of 0.0127 and 0.0002, respectively, while those through hand-to-nose transmission from nonporous and porous environments had LN distributions with GMs of 0.0006 and 0.0000, GDs of 43.2310 and 47.3372, and medians of 0.0009 and 0.0000, respectively. The probability of infection through hand-to-eye transmission from a nonporous environment had a beta distribution with α = 2.38803, ß = 13.60457, a minimum of 0.0045, a maximum of 0.9021, and a median of 0.1179, while that from a porous environment had a Weibull distribution with a scale parameter of 0.0030, a shape parameter of 1.323, and a median of 0.0023. CONCLUSION: SARS-CoV-2 infection will occur through hand-to-face contact via contaminated environment.

Face touching in the time of COVID-19 in Shiraz, Iran.

BACKGROUND: Iranian were advice to wear a mask and not touch their face during COVID-19 restrictions in Iran. METHODS: One-thousand people were observed for 15-30 minutes in public places between April 22 and May 9, 2020. The average number of touches to the mucosal zone was calculated per hour and mask wearers (N = 568) were compared with those not wearing a mask (N = 432). FINDINGS: Ninety-two percent were observed touching their face at least once an hour and averaged 10 (SD 6) touches per hour. Nonmask wearers touched their face significantly more often than mask wearers (11 vs 8 times per hour, P < .001). Nonmask wearers were 1.5 (95%CI OR 1.2-2.0) times more likely to touch their mucosal zone than mask wearers (P < .001). CONCLUSION: Face touching is a common behavior and may have a role in COVID-19 transmission in the absence of hand hygiene. Mask use decrease the frequency of touching the mucosal zone.