Povidone-iodine hand wash and hand rub products demonstrated excellent in vitro virucidal efficacy against Ebola virus and modified vaccinia virus Ankara, the new European test virus for enveloped viruses

Background: The recent Ebola virus (EBOV) epidemic highlights the need for efficacious virucidal products to help prevent infection and limit the spread of Ebola virus disease. However, there is limited data on the efficacy of virucidal products against EBOV, because the virus has a high biosafety level and is only available in a few laboratories worldwide. The virucidal efficacy of antiseptics and disinfectants can be determined using the European Standard EN14476:2013/FprA1:2015. Modified vaccinia virus Ankara (MVA) was introduced in 2014 as a reference virus for the claim 'virucidal active against enveloped viruses for hygienic hand rub and hand wash'. For EBOV, also an enveloped virus, the suitability of MVA as a surrogate needs to be proven. The aim of this study was to test the in vitro efficacy of four povidone iodine (PVP-I) formulations against EBOV: 4 % PVP-I skin cleanser; 7.5 % PVP-I surgical scrub; 10 % PVP-I solution; and 3.2 % PVP-I and 78 % alcohol solution. The formulations were tested with MVA to define the test conditions, and as a secondary objective the suitability of MVA as a surrogate for enveloped viruses like EBOV was assessed. Methods: According to EN14476, a standard suspension test was used for MVA. Large-volume plating was used for EBOV to increase test sensitivity and exclude potential after-effects. All products were tested under clean (0.3 g/L BSA) and dirty (3.0 g/L BSA + 3.0 mL/L erythrocytes) conditions with MVA for 15, 30, and 60 s. The concentration-contact time values obtained with MVA were verified for EBOV. Results: Viral titres of MVA and EBOV were reduced by >99.99 % to >99.999 % under clean and dirty conditions after application of the test products for 15 seconds. Conclusions: All products showed excellent virucidal efficacy against EBOV, demonstrating the important role PVP-I can play in helping to prevent and limit the spread of Ebola virus disease. The efficacy against both test viruses after 15 s is helpful information for the implementation of guidance for people potentially exposed to EBOV, and confirms the excellent virucidal efficacy of PVP-I against enveloped viruses. MVA was found to be a suitable surrogate for enveloped viruses like EBOV.