• Administering Vaccines
  • Vaccine Administration Errors
  • Combination Vaccines
  • MMRV (ProQuad, Merck)

An expired dose of ProQuad (MMRV, Merck) was given to a patient. We assume that the repeat dose should be given in three months because the spacing between doses of a combination vaccine depends on the longest minimum interval of a component (in this case the varicella vaccine component). Is this correct?

In the case of an expired live vaccine, the issue is not necessarily the routine minimum interval (three months in the case of varicella and ProQuad vaccines), but the interval that would prevent viral interference if the expired vaccine happened to be still viable. This interval is considered to be four weeks (28 days). The repeat dose should be administered four weeks after the expired dose.

Last reviewed: July 15, 2023

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