Vaccine Expiration Date Interpretation
Vaccines expire at the end of the last day of the month printed on the expiration date, meaning they can be used through the final day of that month. This is the standard interpretation for pharmaceutical products unless otherwise specified by the manufacturer.
Key Principles for Vaccine Expiration
Vaccines that are beyond their expiration date should not be administered, as stated by the Advisory Committee on Immunization Practices (ACIP) 1.
If expired vaccines are administered inadvertently, they should not be counted as valid doses and must be repeated (unless serologic testing indicates an adequate immune response) 1.
The expiration date printed on vaccine vials or packaging represents the last date through which the vaccine can be used, which includes the entire final day of that month 1.
Practical Application
A vaccine with an expiration date of "March 2024" can be used through March 31,2024 (through the end of the last day of the month).
On April 1,2024, that same vaccine would be considered expired and should not be administered 1.
For multidose vials that have been opened, remaining doses can be administered until the expiration date printed on the vial, provided proper storage conditions have been maintained and the vaccine is not visibly contaminated 1.
Special Considerations for Reconstituted Vaccines
- Live attenuated vaccines have much shorter expiration times after reconstitution, regardless of the printed expiration date 1:
- Varicella vaccine: must be used within 30 minutes
- Yellow fever vaccine: must be used within 1 hour 1
- MMR vaccine: must be used within 8 hours
Critical Storage Reminders
Vaccine quality depends on maintaining the cold chain from manufacture through administration, and mishandled vaccines may appear identical to potent vaccines 1.
When uncertain about vaccine handling or expiration status, contact the manufacturer for guidance 1.
Administering an expired vaccine dose requires repeating the vaccination following a 28-day interval with a non-expired vaccine 1.