M-M-R II®/PRIORIX®
Measles, Mumps, Rubella Vaccine
Version 2025-04 · Last reviewed April 1, 2025 · Methodology
List Price
$130
With Insurance
$0
How It Works
The MMR vaccine contains live, weakened (attenuated) measles, mumps, and rubella viruses. The attenuated viruses replicate briefly in the body — not enough to cause disease, but enough to generate a full, long-lasting immune response similar to natural infection.
Why the side effects happen
Because the vaccine uses live (though weakened) viruses, it can cause mild versions of the disease symptoms: rash, low fever, brief joint pain 1–3 weeks after vaccination. These are immune activation effects, not infection. Serious reactions (febrile seizure, thrombocytopenia) are rare — and occur at far lower rates than with actual measles infection.
When Will I Feel It?
Protection develops 2–4 weeks after vaccination. Two doses (12–15 months, then 4–6 years) provide lifelong protection in most people.
Full protection established. Antibody titers at peak.
97% of people remain immune after two doses. Some may need a booster in high-exposure settings.
Medical Disclaimer
The information on this page is compiled from publicly available clinical trial data, FDA prescribing information, and peer-reviewed literature. It is provided for educational purposes only and does not constitute medical advice, diagnosis, or treatment recommendations. Individual responses to medications vary. Always consult a qualified healthcare provider before starting, stopping, or changing any medication.
Common Side Effects
While taking this medication, you may experience the following common side effects. We've included tips on how to manage them.
Injection site pain / redness
25-30%Normal immune response; apply ice for 10-20 minutes after
Fever (low-grade)
5-15%Typically peaks 7-12 days post-vaccination; acetaminophen can help
Mild rash
5%Non-contagious rash may appear 7-12 days post-vaccination
Temporary swollen glands (neck/jaw)
5%Normal immune response; usually resolves within a few weeks
Mild joint aching (rubella component)
20-25% in adult womenCan occur 1-3 weeks post-vaccination; usually brief
Temporary stiffness in joints
10-15% adult womenFrom the rubella component; usually self-limited
Runny nose / mild upper respiratory symptoms
5%Not contagious; resolves within a few days
Temporary low platelet count (ITP)
1 in 30,000Usually mild and resolves spontaneously; monitor for unusual bruising
Temporary mild decrease in white blood cells
UncommonDetected on lab tests; usually self-resolving
Parotid swelling (mumps component)
RareRare case of mild parotid gland swelling; self-limiting
Serious Adverse Effects
- • Febrile seizures: 1 in 3,000 doses
- • Anaphylaxis: ~1-2 per million doses
- • Encephalitis: ~1 per million doses
- • Immune thrombocytopenic purpura (ITP): ~1 per 30,000
Drug Interactions
Major Interactions (Avoid)
Moderate Interactions (Caution)
When to Contact Your Doctor
This medication requires ongoing medical supervision. The following situations warrant a prompt conversation with your prescribing physician — do not wait for your next scheduled appointment.
Contact soon if you notice
- Febrile seizures: 1 in 3,000 doses
- Anaphylaxis: ~1-2 per million doses
- Encephalitis: ~1 per million doses
- Immune thrombocytopenic purpura (ITP): ~1 per 30,000
Also discuss if you want to
- Review whether this medication is still appropriate for you
- Consider dosage adjustments based on response
- Explore lifestyle or non-drug alternatives
- Understand stopping or tapering options
- Plan monitoring labs and follow-up
In the US, call 911 or go to the nearest emergency room for severe symptoms. Poison Control: 1-800-222-1222.
FDA Adverse Event Reports
Patient-filed reports from the FDA FAERS database · refreshed daily
Community Reports
User-reported experiences — anonymous & anecdotal
Medical Disclaimer
The information on this page is compiled from publicly available clinical trial data, FDA prescribing information, and peer-reviewed literature. It is provided for educational purposes only and does not constitute medical advice, diagnosis, or treatment recommendations. Individual responses to medications vary. Always consult a qualified healthcare provider before starting, stopping, or changing any medication.
Metabolic & Lifestyle Alternatives
Immune Health & Contextual Information
MMR provides highly effective protection (>97%) against measles, mumps, and rubella; measles alone causes an estimated 100,000+ deaths annually in unvaccinated populations globally
Important context: Evidence quality varies across these approaches. Some are well-studied with randomized controlled trial data; others are based on observational or smaller studies. These interventions are not guaranteed to replace medication for all patients. Discuss with your doctor whether any of these are appropriate for your clinical situation.
Global Prescribing & Pricing
MMR is universal globally — mandatory programs achieve 97% coverage vs. voluntary programs' 91%
United States
Free (VFC) / $90–150 uninsured/mo
91–93% childhood coverage — below the 95% herd immunity threshold
Voluntary with state school entry requirements; no national mandate; coverage gaps persist
Free via VFC for uninsured children; covered by most insurance
Germany
Free/mo
97% coverage — highest in EU; mandatory since 2020
Made mandatory for school and daycare entry in 2020 following measles outbreaks; highest EU coverage
Free — mandatory program
Australia
Free (NIP)/mo
96% coverage — above herd immunity threshold
National immunization schedule with digital reminder systems; No Jab No Pay welfare rules
Free — National Immunisation Program
United Kingdom
Free (NHS)/mo
94% coverage — near herd immunity threshold
NHS maternal recall system + GP follow-up letters; childhood schedule fully integrated
Free — NHS
Japan
~$54 (municipally subsidized)/mo
94% coverage — strong public health campaigns
Routine 2-dose schedule; municipal-level vaccine promotion; MMR suspended 1993–2006 due to mumps strain concerns
Subsidized by municipalities
Germany's 2020 mandatory MMR law — passed after measles outbreaks — pushed coverage from 93% to 97% within two years. Australia ties vaccine compliance to welfare payments (No Jab No Pay), achieving 96%. The US relies on state-level voluntary requirements and has never crossed the 95% herd immunity threshold nationally.
Clinical Trials & Funding
Understanding who funds research helps contextualize results. Industry-funded trials are not automatically invalid — they undergo the same FDA review — but declared conflicts and sponsor effects are worth knowing. All linked trials can be verified on ClinicalTrials.gov.
Funding Sources
Merck funded original trials. Post-marketing surveillance is government/CDC-led. Whistleblower lawsuit alleged Merck manipulated mumps efficacy data (settled 2023 without admission).
Declared Conflicts of Interest
Merck settled a lawsuit with former employees who claimed efficacy was inflated. ACIP members with Merck ties voted on schedules. The fraudulent Wakefield autism study (1998, fully retracted) caused lasting vaccine hesitancy.
Key Efficacy Results
Measles efficacy ~97%, Rubella ~97%, Mumps ~88% (more variable)
Referenced Studies
Each study carries a Cochrane RoB-2 risk-of-bias badge — tap the badge for details.
Evidence & Transparency
Cochrane RoB-2 (Risk of Bias)
Badges reflect an editorial assessment using Cochrane's RoB-2 tool domains: randomization, intervention deviation, missing data, outcome measurement, and selective reporting. These are not certified Cochrane reviews. Learn more ↗
CMS Open Payments
Manufacturer payment disclosures are reported via the CMS Sunshine Act. Disclosure is legally required and does not imply bias or misconduct. Language uses "may," "suggests," or "appears" — never definitive clinical claims. CMS Open Payments ↗
Live Clinical Trials
Live from ClinicalTrials.gov · refreshed every 4 hours
Currently enrolling, active, and recently completed studies involving Measles, Mumps, Rubella Vaccine. Data is pulled directly from the U.S. National Library of Medicine.
Recent Research
Live from PubMed · peer-reviewed literature · refreshed every 4 hours
Most recently indexed clinical trials and systematic reviews mentioning Measles, Mumps, Rubella Vaccine in PubMed.
Source Documentation
Structured citations for referenced clinical trials
Each referenced trial is listed with its registry ID, funding source, and bias assessment. Use the copy button to generate a formatted citation.
| Trial | Registry ID | Cite |
|---|---|---|
| MMR Immunogenicity (GSK vs M-M-R II) | NCT00861744 |
Bias ratings use Cochrane RoB-2 methodology. Editorial assessment — not a certified Cochrane review.
Our MethodologyMedical Disclaimer
The information on this page is compiled from publicly available clinical trial data, FDA prescribing information, and peer-reviewed literature. It is provided for educational purposes only and does not constitute medical advice, diagnosis, or treatment recommendations. Individual responses to medications vary. Always consult a qualified healthcare provider before starting, stopping, or changing any medication.
Stopping This Medication Safely
MMR is a childhood vaccine series given in 2 lifetime doses. There is no ongoing medication to taper — immunity is expected to be lifelong after the 2-dose series.
Never change or stop a medication without consulting your prescribing physician.
Questions for Your Doctor
Questions to Ask
- 1.Do I need a titer test to confirm immunity?
- 2.Is there a history of egg allergy concerns?
- 3.Should my child get MMRV (with varicella)?
- 4.Are there any immunocompromising conditions to consider?
Lab Tests to Request
- MMR titer (IgG antibody test if unsure of history)
- Immune status check
- Pregnancy test (women of childbearing age)
Medical Disclaimer
The information on this page is compiled from publicly available clinical trial data, FDA prescribing information, and peer-reviewed literature. It is provided for educational purposes only and does not constitute medical advice, diagnosis, or treatment recommendations. Individual responses to medications vary. Always consult a qualified healthcare provider before starting, stopping, or changing any medication.
Frequently Asked Questions About M-M-R II®/PRIORIX®
- What is M-M-R II®/PRIORIX® used for?
- M-M-R II®/PRIORIX® (Measles, Mumps, Rubella Vaccine) is a Vaccine (Live Attenuated) manufactured by Merck / GSK. FDA-approved indications include: Measles prevention; Mumps prevention; Rubella prevention; Congenital rubella syndrome prevention.
- What are the common side effects of M-M-R II®/PRIORIX®?
- Common side effects of M-M-R II®/PRIORIX® include: Injection site pain / redness (25-30%); Fever (low-grade) (5-15%); Mild rash (5%); Temporary swollen glands (neck/jaw) (5%); Mild joint aching (rubella component) (20-25% in adult women).
- How much does M-M-R II®/PRIORIX® cost?
- M-M-R II®/PRIORIX® list price is approximately $130. With insurance it typically costs $0; without insurance approximately $80-150 per dose.
- Who funded the clinical trials for M-M-R II®/PRIORIX®?
- Merck funded original trials. Post-marketing surveillance is government/CDC-led. Whistleblower lawsuit alleged Merck manipulated mumps efficacy data (settled 2023 without admission).
- How strong is the clinical evidence for M-M-R II®/PRIORIX®?
- Key studies: Pre-licensure efficacy studies, post-marketing surveillance. Measles efficacy ~97%, Rubella ~97%, Mumps ~88% (more variable) Potential conflicts of interest: Merck settled a lawsuit with former employees who claimed efficacy was inflated. ACIP members with Merck ties voted on schedules. The fraudulent Wakefield autism study (1998, fully retracted) caused l.
- Are there non-drug alternatives to M-M-R II®/PRIORIX®?
- MMR provides highly effective protection (>97%) against measles, mumps, and rubella; measles alone causes an estimated 100,000+ deaths annually in unvaccinated populations globally See the Alternatives tab for full details.
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