Impact of concentration, temperature and pH on the virucidal activity of alcohols against human adenovirus.

BACKGROUND: Adenoviruses belong to the stable non-enveloped viruses playing an important role in healthcare-associated infections mainly causing respiratory infections and epidemic keratoconjunctivitis. Hand disinfection with alcoholic preparations is therefore one of the most important measures to prevent such viral infections in hospitals and other medical settings.

METHODS: The inactivation of adenovirus type 5 by ethanol, 1- and 2-propanol and two commercially available hand disinfectants was examined at different concentrations, temperatures, and pH-values.

RESULTS: For ethanol and 1-propanol the maximum virus-inactivating properties after 30 seconds exposure were found at a concentration of 60-70% and 50-60%, respectively, whereas with 2-propanol no activity was observed. The virucidal activity of all alcohols and the two hand disinfectants examined was increased when raising the temperature from 20°C up to 25°C. By increasing the pH value to 9, a strong improvement of the activity of ethanol, 1-propanol and one hand disinfectant was observed, whereas pH lowering resulted in decrease of activity.

CONCLUSION: These results demonstrate the importance of physical parameters in the inactivation of adenoviruses by alcohols and will help to improve measures to reduce adenovirus transmission in healthcare settings.