M-M-R II

M-M-R II
Type	Combination vaccine
Target	Measles, Mumps, Rubella
Tradename	M-M-R II
Manufacturer	Merck & Co.
Routes of administration	Subcutaneous injection
ATC prefix	J07
ATC suffix	BD52

M-M-R II. It is a combination vaccine used for immunization against measles, mumps, and rubella. Developed and manufactured by Merck & Co., it is a live, attenuated vaccine administered via subcutaneous injection. The vaccine is a cornerstone of public health programs globally, playing a critical role in reducing the incidence of these once-common childhood diseases.

Composition and formulation

The vaccine contains live, attenuated strains of the measles virus, the mumps virus, and the rubella virus. The measles component is derived from the Enders' attenuated Edmonston strain, propagated in chick embryo cell culture. The mumps component originates from the Jeryl Lynn strain, isolated by Maurice Hilleman from his daughter. The rubella component is the Wistar RA 27/3 strain, developed at the Wistar Institute. Excipients include sorbitol, sucrose, hydrolyzed gelatin, and a trace amount of neomycin. The formulation is a lyophilized powder that is reconstituted with a sterile diluent provided by the manufacturer, Merck & Co., before administration.

Indications and usage

M-M-R II is indicated for simultaneous vaccination against measles, mumps, and rubella in individuals 12 months of age and older. Its primary use is in routine childhood immunization schedules as recommended by the Advisory Committee on Immunization Practices and the World Health Organization. It is also recommended for certain adolescents and adults without evidence of immunity, particularly women of childbearing age to prevent congenital rubella syndrome. The vaccine may be administered in outbreak settings as determined by public health authorities like the Centers for Disease Control and Prevention.

Efficacy and clinical trials

Clinical trials and extensive post-marketing surveillance have demonstrated high efficacy for M-M-R II. Following two doses, the vaccine is approximately 97% effective against measles and 88% effective against mumps. Efficacy against rubella is greater than 95%. Pivotal studies leading to licensure by the Food and Drug Administration involved large cohorts of children in the United States and Finland. Long-term follow-up studies, including work published in the Journal of the American Medical Association, have confirmed that immunity is durable in most vaccinated individuals for decades, though some data from the National Institutes of Health suggest potential waning of mumps immunity over time.

Safety and adverse effects

The vaccine is generally well-tolerated, with common adverse reactions including fever and a mild rash. Less frequently, temporary joint pain may occur, particularly in post-pubertal females. Extensive review by the Institute of Medicine has found no causal link between the vaccine and autism. Rare serious adverse events, such as febrile seizures or transient thrombocytopenia, occur at very low rates. Surveillance systems like the Vaccine Adverse Event Reporting System and the Vaccine Safety Datalink continuously monitor its safety profile. Contraindications include severe immunodeficiency, pregnancy, and a history of anaphylactic reactions to components like neomycin.

Administration and dosage

The vaccine is administered as a 0.5 mL dose via subcutaneous injection, typically in the outer aspect of the upper arm. The first dose is routinely given at 12 through 15 months of age. A second dose is administered between 4 and 6 years of age, as per the schedule from the American Academy of Pediatrics. It can be administered concurrently with other vaccines, such as the varicella vaccine, at separate sites. For adults and adolescents without proof of immunity, at least one dose is recommended, with specific guidance provided for healthcare workers and international travelers by the Centers for Disease Control and Prevention.

History and development

The development of M-M-R II is rooted in the work of pioneers like John Enders, Maurice Hilleman, and Stanley Plotkin. Individual vaccines for measles, mumps, and rubella were first licensed in the United States in 1963, 1967, and 1969, respectively. Merck & Co. researcher Maurice Hilleman led the effort to combine the three attenuated viruses into a single trivalent vaccine, which was first licensed in 1971. The current formulation, M-M-R II, which uses the improved RA 27/3 rubella strain, replaced the original in 1979. Its introduction and widespread use have led to the elimination of endemic measles and rubella in the Americas, a milestone verified by the Pan American Health Organization.

Category:Vaccines Category:Merck & Co.