Shingrix, unlike Zostavax, is not a live vaccine. Therefore, being on an antiviral medication such as acyclovir, Valtrex (valacyclovir) or famciclovir theoretically should not be a concern with Shingrix. In addition, the prescribing information for Shingrix does not list any antiviral as interacting with Shingrix. In fact, it only lists immunosuppressive therapies as interacting medications as they may reduce the effectiveness of Shingrix.
Nevertheless, as there is a lack of data regarding the potential interaction with antiviral medication and Shingrix, your doctor may recommend simply following the recommendations in place for Zostavax, which is a live vaccine, and is known to be affected by antiviral drugs. The recommendation for Zostavax is:
- Zostavax should be administered at least 24 hours after stopping your antiviral drug (e.g. valacyclovir). The antiviral should not be started again for at least 14 days after vaccination per the Immunization Action Coalition.
As stated above however, any antiviral therapy is unlikely to interfere with the effectiveness of Shingrix.
- Shingrix is not a live vaccine and therefore, should theoretically not interact with antiviral medication.
- There is a lack of data available regarding immunization with Shingrix while taking antiviral medication and a cautious approach may therefore be recommended.