There is no waiting period. The varicella vaccine dose can be given at any time after the Shingrix dose. Review your procedures to prevent this from happening again. Always check the label 3 times to ensure you are administering the product intended. Such an error also should be reported to the Vaccine Adverse Event Reporting System (VAERS) by phone 1-800-822-7967 or online at https://vaers.hhs.gov.