Reducing viral contamination from finger pads: handwashing is more effective than alcohol-based hand disinfectants

Background - Hand hygiene is important for interrupting transmission of viruses through hands. Effectiveness of alcohol-based hand disinfectant has been shown for bacteria but their effectiveness in reducing transmission of viruses is ambiguous. Aim - To test efficacy of alcohol hand disinfectant against human enteric and respiratory viruses and to compare efficacy of an alcohol-based hand disinfectant and handwashing with soap and water against norovirus. Methods - Efficacies of a propanol and an ethanol-based hand disinfectant against human enteric and respiratory viruses were tested in carrier tests. Efficacy of an alcohol-based hand disinfectant and handwashing with soap and water against noroviruses GI.4, GII.4, and MNV1 were tested using finger pad tests. Findings - The alcohol-based hand disinfectant reduced the infectivity of rotavirus and influenza A virus completely within 30 s whereas poliovirus Sabin 1, adenovirus type 5, parechovirus 1, and MNV1 infectivity were reduced 3.0 ± 0.4 log10) was significantly higher than treating hands with alcohol (2.8 ± 1.5 log10). Washing with soap and water for 30 s removed genomic copies of MNV1 (>5 log10), noroviruses GI.4 (>6 log10), and GII.4 (4 log10) completely from all finger pads. Treating hands with propanol-based hand disinfectant showed little or no reduction to complete reduction with mean genomic copy reduction of noroviruses GI.4, GII.4, and MNV1 being >2.6, >3.3, and >1.2 log10 polymerase chain reaction units respectively. Conclusions - Washing hands with soap and water is better than using alcohol-based hand disinfectants in removing noroviruses from hands. Keywords: Carrier test; Enteric virus; Finger pad test; Foodborne viruses; Hand disinfection; Norovirus; Respiratory viruses