Study	Reason for exclusion
Baranova 2013	Not RCT; seemed to use interferon rather than an antiviral as the intervention
Bolden 1972	Not our intervention of interest; examined corticosteroids
Candy 2002	Not RCT
Duan 2009	Not our intervention of interest; studied Chinese medicine
Ebell 2004	Not RCT
Gordeets 2011	Not RCT
Lin 1985	Only examines in‐vitro studies
Sichko 1987	Not our intervention of interest; studied ribonuclease
Sinha 1971	This study examined methisazone which is an antiviral drug. However, it was never licensed in Ireland, and the UK licence was stopped in 1983 so we felt it was justified not to include this study.
Torre 1999	Not RCT
Tynell 1996	Intervention is acyclovir and steroid versus placebo. No arm with acyclovir on its own
Usami 2013	Not RCT
Wood 1997	Not RCT

RCT: randomised controlled trial