Effect of acyclovir combined with other antiherpetic agents on varicella zoster virus in vitro

The sensitivity of varicella zoster virus (VZV) strain Ellen to acyclovir in combination with other antiherpetic agents in vitro has been examined by the plaque-reduction and infectious center assay methods. (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU), trifluorothymidine (TFT), or 5-iodo-2'-deoxyuridine (IdUrd) produced, in general, additive antiviral activity when examined by either assay method. Acyclovir in combination with phosphonoacetate (PAA) resulted in additive effects as measured by the plaque-reduction assay. The combination of acyclovir with 9-beta-D-arabinofuranosyladenine (ara-A) gave generally additive or occasionally synergistic antiviral activity when tested in MRC-5 or WI-38 cells respectively, regardless of assay method.