The amount of time in which a dose of vaccine must be used after reconstitution varies by vaccine and is usually outlined in the vaccine’s package insert. MMR must be used within 8 hours of reconstitution. MMRV must be used within 30 minutes; other vaccines must be used “immediately,” which is not a clearly defined term but may be considered to be within 30 minutes. Immunize.org has a staff education piece that outlines the time allowed between reconstitution and use, as stated in the package inserts for a number of vaccines. This handout can be found at the following link: www.immunize.org/wp-content/uploads/catg.d/p3040.pdf.
Last reviewed:
August 10, 2026
MMRII (Merck) brand of MMR vaccine may be stored either in the refrigerator at 2°C to 8°C (36°F to 46°F) or in the freezer at -50°C to -15°C (-58°F to +5°F). Prescribing information for the Priorix (GSK) brand of MMR vaccine states that it should be stored refrigerated (at 2°C to 8°C), but not in the freezer. For both brands, the diluent should not be frozen and can be stored in the refrigerator or at room temperature.
If the MMR is combined with varicella vaccine as MMRV (ProQuad, Merck), it must be stored in the freezer at -50°C to -15°C (-58°F to +5°F).
Last reviewed:
August 10, 2026
Unfortunately, serious errors in vaccine storage and handling like this occur too often. If you suspect that vaccine has been mishandled, you should take the following steps: label the affected vaccine package clearly so it will not be used before knowing whether it is still usable, return the vaccine to recommended storage conditions, and then contact the manufacturer or state/local health department for guidance on whether it is still usable or should be wasted. This is particularly important for live virus vaccines like MMR and varicella.
Last reviewed:
August 10, 2026
The guidance for handling after reconstitution is the same for both brands of MMR vaccine (MMRII and Priorix). It is preferable to administer MMR immediately after reconstitution. If not used immediately, the reconstituted vaccine should be store refrigerated (2°C to 8°C [36°F to 46°F]) until use. If reconstituted MMR is not used within 8 hours, it must be discarded.
Last reviewed:
August 10, 2026
Only the diluent supplied with the MMR vaccine should be used to reconstitute any vaccine. A vaccine reconstituted with the incorrect diluent should not be used. If administered, the dose should be repeated.
Last reviewed:
August 10, 2026
