9 March 2023 - - The US Food and Drug Administration has approved the addition of the intramuscular route of administration to the United States Product Insert for US-based pharmaceutical company Merck's (NYSE: MRK) MMRV family of vaccines: M-M-RII, VARIVAX, and ProQuad, the company said.

While these vaccines have a long history in the US, until now they have only been administered via subcutaneous injection.

With these approvals, healthcare professionals now have the option to choose to administer all routinely recommended injectable pediatric vaccinations included in the CDC immunization schedule, via the same IM route.

In the US, the only measles, mumps, rubella, and varicella vaccines that can be administered IM are M-M-RII, VARIVAX, and ProQuad.

Additionally, the MMRV family of vaccines has already been licensed for IM administration in the European Union.

ProQuad is a vaccine indicated for active immunization for the prevention of measles, mumps, rubella, and varicella in children 12 months through 12 years of age.

It was approved by the FDA in 2005. VARIVAX is a vaccine indicated for active immunization for the prevention of varicella in individuals 12 months of age or older.

It received FDA approval in 1995 and remains the only varicella vaccine available for use in the US M-M-RII is indicated for active immunization for the prevention of measles, mumps, and rubella in individuals 12 months of age or older and received FDA approval in 1978.

ProQuad is a vaccine indicated for active immunization for the prevention of measles, mumps, rubella, and varicella in children 12 months through 12 years of age.

VARIVAX is a vaccine indicated for active immunization for the prevention of varicella in individuals 12 months of age or older.

M-M-RII is indicated for active immunization for the prevention of measles, mumps, and rubella in individuals 12 months of age or older.

Hypersensitivity: ProQuad, M-M-RII, and VARIVAX are contraindicated in patients with a history of anaphylactic reaction or hypersensitivity to any component of the vaccine (including gelatin or neomycin) or to a prior dose of measles, mumps, rubella, or varicella-containing vaccine.

Use caution when administering ProQuad and M-M-RII to individuals with anaphylaxis or immediate hypersensitivity to eggs.

ProQuad, M-M-RII, and VARIVAX are contraindicated in certain individuals, including those with: immunodeficiency or who are immunosuppressed; an active febrile illness; untreated tuberculosis.

Pregnancy: ProQuad, M-M-RII, and VARIVAX are contraindicated for use in pregnant women.