For an extended period, the temperature in the vaccine-storage refrigerator in our practice was too cold. We assume all the vaccines given during that period are considered invalid. How should we schedule the revaccinations?

If administered vaccine is found to be stored at an inappropriate temperature, whether too cold or too warm, the provider should contact the state health department to determine whether the vaccine dose is invalid. If the vaccine dose is determined to be invalid, another dose should be given. This applies to both inactivated and live vaccines. If the damaged vaccine was a live virus vaccine (e.g., MMR, MMRV, VAR), you should wait at least 4 weeks after the previous (damaged) dose was given before repeating it. If the damaged vaccine was an inactivated vaccine, you can give the repeat dose on the same day you gave the damaged dose or at any other time, with one exception. The exception is Shingrix (herpes zoster vaccine), which should be repeated at least 28 days later due to the potential for increased side effects due to the chemical adjuvant it contains to enhance its effectiveness. If you prefer, you can perform serologic testing to check for immunity for certain vaccinations (e.g., measles, rubella, hepatitis A, diphtheria, varicella, and tetanus).