A novel antiviral formulation inhibits a range of enveloped viruses.

Nicola F Fletcher; Luke W Meredith; Emma L Tidswell; Steven R Bryden; Daniel Gonçalves-Carneiro; Yasmin Chaudhry; Claire Shannon-Lowe; Michael A Folan; Daniella A Lefteri; Marieke Pingen; Dalan Bailey; Clive S McKimmie; Alan W Baird

We investigated the effect of a specifically formulated emulsion of free fatty acids, ViroSAL, on infectivity of enveloped and non-enveloped viruses. Caprylic acid delivered in the ViroSAL emulsion exhibited significant anti-viral effects. A range of enveloped viral infection systems was utilized, and complete inhibition of viral infection was observed without any evidence of cytotoxicity. ViroSAL had no effect on the infectivity of a non-enveloped virus, norovirus, which is in agreement with previous studies demonstrating that free fatty acids are ineffective against nonenveloped viruses (Thormar et al., 1987 , Kohn et al., 1980 . Furthermore, ViroSAL inactivated the enveloped mosquito-borne viruses Semliki Forest virus (SFV) and Zika virus (ZIKV) in vitro. Prophylactic topical treatment of viral infection in mosquito bites with ViroSAL inhibited local replication and dissemination of SFV and plasma levels of ZIKV in mice. Transmission electron microscopy analysis indicated that ViroSAL disrupts orf parapoxvirus envelope integrity, with higher concentrations completely disrupting virion morphology. These data indicate that ViroSAL has antiviral activity against a range of enveloped viruses in vitro and in vivo.