All live injected vaccines (MMR, varicella, and yellow fever) are recommended to be given subcutaneously (Subcut). In February 2023, FDA approved the administration of MMRII (Merck) brand of MMR by either Subcut or IM routes. The Priorix (GSK) brand of MMR is approved only for Subcut administration. Intramuscular (IM) administration of any of these live virus vaccines is not likely to decrease immunogenicity, and doses given IM do not need to be repeated. When administering MMRII by the IM route, select an appropriate needle length for the patient’s size. See Immunize.org’s clinical resource “Administering Vaccines: Dose, Route, Site, and Needle Size” at www.immunize.org/catg.d/p3085.pdf.
Ask the Experts: MMR (Measles, Mumps, and Rubella): Administering Vaccines
Yes. A 5/8″ needle is recommended for subcutaneous injections for people of all sizes. See Immunize.org’s clinical resource “How to Administer Intramuscular and Subcutaneous Vaccine Injections” at www.immunize.org/catg.d/p2020.pdf.
Yes, however, this issue is not addressed in the 2010 MMRV ACIP recommendations. Although this is off-label use, CDC recommends that when a dose of MMRV is inadvertently given to a patient age 13 years and older, it may be counted towards completion of the MMR and varicella vaccine series and does not need to be repeated.