Inhibition of SARS coronavirus infection in vitro with clinically approved antiviral drugs

Abstract

Severe acute respiratory syndrome (SARS) is an infectious disease caused by a newly identified human coronavirus (SARS-CoV). Currently, no effective drug exists to treat SARS-CoV infection. In this study, we investigated whether a panel of commercially available antiviral drugs exhibit in vitro anti-SARS-CoV activity. A drug-screening assay that scores for virus-induced cytopathic effects on cultured cells was used. Tested were 19 clinically approved compounds from several major antiviral pharmacologic classes: nucleoside analogs, interferons, protease inhibitors, reverse transcriptase inhibitors, and neuraminidase inhibitors. Complete inhibition of cytopathic effects of SARS-CoV in culture was observed for interferon subtypes, b-1b, a-n1, a-n3, and human leukocyte interferon a. These findings support clinical testing of approved interferons for the treatment of SARS.

Figure 1

Microscopic appearance of control (a) and infected (b) Vero E6 cells demonstrating cytopathic effects.

Figure 2

Dose-response curves for Alferon (a), Betaferon (b), and Multiferon (c) as determined by plaque reduction assays. IC₅₀ (50% inhibitory concentration) and IC₉₅ (95% inhibitory concentration) values were calculated by using the fitted functions describing the curves.