Last reviewed 2026-04-22 · How we verify

Comparator: ProQuad™ (V221)

ProQuad is a live attenuated combination vaccine that stimulates immune response against measles, mumps, rubella, and varicella viruses.

ProQuad is a live attenuated combination vaccine that stimulates immune response against measles, mumps, rubella, and varicella viruses. Used for Prevention of measles, mumps, rubella, and varicella in children and adults.

At a glance

Mechanism of action

ProQuad contains live weakened strains of measles, mumps, rubella, and varicella-zoster viruses that replicate in vaccinated individuals, triggering both humoral and cell-mediated immune responses. This results in the production of antibodies and T-cell immunity against all four viruses, providing protection against these infectious diseases. The vaccine is administered as a single injection combining what were previously given as separate MMR and varicella vaccines.

Approved indications

• Prevention of measles, mumps, rubella, and varicella in children and adults

Common side effects

• Injection site reactions (erythema, swelling, tenderness)
• Fever
• Rash
• Varicella-like rash

Key clinical trials

• V221 Concomitant Use Study With Pneumococcal Conjugate Vaccine (V221-019) (PHASE3)
• ProQuad™ Versus M-M-R II™ and VARIVAX™ in Healthy Children (V221-009)(COMPLETED) (PHASE3)

Primary sources

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Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Comparator: ProQuad™ (V221) CI brief — competitive landscape report
• Comparator: ProQuad™ (V221) updates RSS · CI watch RSS
• Merck Sharp & Dohme LLC portfolio CI