MMR, MMRV and varicella vaccines: Priorix, M-M-R II, ProQuad and Varivax

The disease and why it matters

Measles is an acute viral respiratory illness with a prodrome of fever (as high as 105 °F), malaise, cough, coryza and conjunctivitis, Koplik spots, and then a maculopapular rash that usually appears about 14 days after exposure; patients are contagious from 4 days before to 4 days after the rash appears. ^[1]

Of every 1,000 measles cases, 1 will develop acute encephalitis (often with permanent brain damage), and 1 to 3 of every 1,000 infected children will die of respiratory and neurologic complications; measles can also cause immune amnesia, a temporary loss of immunity to other diseases. ^[1]

Mumps causes fever, headache, muscle aches, tiredness, loss of appetite and swollen, tender salivary glands, and can lead to deafness, swelling of the brain or spinal cord covering, painful swelling of the testicles or ovaries and, very rarely, death; rubella in pregnancy can cause a miscarriage or serious birth defects. ^[2]

Varicella (chickenpox) is caused by varicella-zoster virus (VZV); the virus then stays latent in the sensory nerve ganglia, and reactivation causes herpes zoster (shingles). The most common complications are bacterial skin and soft-tissue infections in children and pneumonia in adults. ^[3]

Varicella is more contagious than mumps and rubella and less contagious than measles; about 90% of susceptible close contacts get varicella after exposure to a person with disease, and people with breakthrough varicella are also contagious. ^[3]

Video and figures

Video

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October 2026: 3 Severe, and Lesser Known, Outcomes of Measles Infection | Vaccine Education Center
Channel: Vaccine Education Center at CHOP · Uploaded October 1, 2026 · Confirmed available October 12, 2026 · Open on YouTubeRxEvidence has not checked every statement in this video.

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Products available

CDC says single-antigen measles vaccine is not available in the United States; measles vaccine is included in MMR and in MMRV, and MMRV is only licensed for children 1 to 12 years old. The varicella vaccines licensed in the United States are single-antigen varicella vaccine and MMRV. ^{[4] [5]}

All four are lyophilized live vaccines reconstituted with the accompanying sterile diluent (for Priorix, a sterile water diluent prefilled syringe); the single dose after reconstitution is approximately 0.5 mL. ^{[7] [9] [11] [13]}

Label currency as posted by FDA: Priorix page content current as of 03/30/2026 (label 3/2026); M-M-R II and ProQuad pages 11/07/2025 (labels 11/2025); Varivax page 08/23/2023 (label 08/2023). ^{[6] [7] [8] [9] [10] [11] [12] [13]}

Who should get it

Presumptive evidence of immunity to measles, mumps and rubella is written documentation of adequate vaccination, laboratory evidence of immunity, laboratory confirmation of disease, or birth before 1957; verbal reports of vaccination without written documentation should not be accepted. ^[4]

For adults, one dose of MMR vaccine or other presumptive evidence of immunity is sufficient for most; there is no recommendation for a catch-up program among adults for a second dose, and postvaccination antibody testing is not necessary. ^[4]

Two doses at least 28 days apart are recommended for students at post-high school institutions, international travelers 12 months and older, healthcare personnel and close contacts of immunocompromised people who lack evidence of immunity; infants 6 through 11 months who travel internationally should get 1 dose of MMR before departure and then 2 more doses on the routine schedule. ^[15]

Varicella: CDC recommends 2 doses of varicella vaccine for children, adolescents and adults without evidence of immunity, the first dose at 12 through 15 months and the second at 4 through 6 years; people 13 years or older get 2 doses 4 to 8 weeks apart using single-antigen varicella vaccine because MMRV is not approved in this age group. ^[5]

Evidence of immunity to varicella is age-appropriate vaccination documentation (1 dose for children aged 12 months through 3 years; 2 doses for school-age children, adolescents and adults), laboratory evidence of immunity or disease, birth in the United States before 1980 (not for healthcare personnel, pregnant women or immunocompromised people), or provider diagnosis or verification of a history of varicella or herpes zoster. ^[5]

Adults: CDC's July 2025 notes give 1 dose of MMR for adults with no evidence of immunity (2 doses at least 4 weeks apart for students in postsecondary institutions, international travelers, household contacts of immunocompromised people, and HIV with CD4 percentage 15% or more and CD4 count 200 or more for at least 6 months), and for varicella a 2-dose series 4 to 8 weeks apart if the person has had no varicella-containing vaccine. ^[16]

Dosing and schedule, including catch-up

CDC schedule notes (July 2, 2025) for catch-up of unvaccinated children and adolescents: MMR 2-dose series at least 4 weeks apart (MMRV maximum age 12 years; if MMRV is used the minimum interval between MMRV doses is 3 months); varicella in ages 7 to 12 years routine interval 3 months (a dose inadvertently given after at least 4 weeks may be counted as valid) and ages 13 years and older routine interval 4 to 8 weeks with minimum interval 4 weeks. ^[14]

Post-exposure prophylaxis for measles: for people exposed who cannot show presumptive evidence of immunity, CDC lists MMR vaccine if given within 72 hours of initial exposure, or immunoglobulin (IG) if given within 6 days of exposure (0.5 mL/kg intramuscular IG regardless of the contact's immune status); MMR vaccine and IG should not be given simultaneously because that practice invalidates the vaccine. ^[4]

Post-exposure varicella vaccination: people with no evidence of immunity who are eligible should get varicella vaccine after exposure to varicella or herpes zoster, ideally within 3 to 5 days, and it should still be offered if more than 5 days have passed; there are no data on MMRV for post-exposure vaccination. ^[5]

During measles outbreaks CDC says there are no recommendations to receive a third dose of MMR vaccine, though health departments may recommend a second dose for adults, an earlier second dose for children 1 to 4 years, or an early dose for infants 6 to 11 months in affected areas; CDC's adult and child notes refer to mumps outbreak settings (including a third dose of MMR) separately. ^{[15] [16]}

Administration

• Route: Priorix is for subcutaneous use; M-M-R II, ProQuad and Varivax may be given intramuscularly or subcutaneously. ^{[7] [9] [11] [13]}
• Use a sterile syringe free of preservatives, antiseptics and detergents for each reconstitution and injection of M-M-R II, ProQuad and Varivax, because these substances may inactivate the vaccine viruses; reconstitute only with the sterile diluent supplied; gently agitate to dissolve completely and discard if the lyophilized vaccine cannot be dissolved. ^{[9] [11] [13]}
• M-M-R II is a light yellow compact crystalline plug before reconstitution and a clear yellow liquid after; Varivax is a white compact crystalline plug and a clear, colorless to pale yellow liquid after reconstitution; do not use if particulates are present or it appears discolored. ^{[9] [13]}
• Priorix: reconstitute the lyophilized antigen component only with the accompanying sterile water diluent; the reconstituted vaccine should be a clear peach- to fuchsia pink-colored suspension. ^[7]
• Do not combine Varivax with any other vaccine through reconstitution or mixing; discard reconstituted Varivax if not used within 30 minutes and do not freeze it. ^[13]
• Administer M-M-R II immediately after reconstitution; if not used immediately it may be stored at 36 to 46 °F (2 to 8 °C), protected from light, for up to 8 hours and must then be discarded. Priorix is stored refrigerated and used within 8 hours after reconstitution. ^{[9] [7]}
• Immune globulins and other blood products given concurrently may interfere with the expected immune response; the MMR and varicella labels advise against giving them at the same time. ^{[9] [13]}
• Tuberculin skin testing: MMR and varicella vaccination may result in temporary depression of tuberculin (PPD) skin sensitivity. ^{[9] [13]}
• ProQuad may be given concomitantly with Hib and/or hepatitis B vaccine, and with pneumococcal 7-valent conjugate vaccine and/or hepatitis A vaccine, at separate injection sites. ^[11]

Storage and handling

• Varivax before reconstitution: store the lyophilized vaccine in a freezer between −58 °F and +5 °F (−50 °C and −15 °C); it may be held at refrigerator temperature (36 to 46 °F, 2 to 8 °C) for up to 72 continuous hours prior to reconstitution, and vaccine stored at 2 to 8 °C that is not used within 72 hours of removal from freezer storage should be discarded; protect from light. ^[13]
• ProQuad before reconstitution: store in a refrigerator at 2 to 8 °C (36 to 46 °F) or colder; the lyophilized vaccine may also be stored in a freezer and then transferred to a refrigerator but should not be refrozen; do not store at room temperature (discard if inadvertently stored at room temperature); protect from light at all times. ^[11]
• M-M-R II: to maintain potency, store between −58 °F and +46 °F (−50 °C to +8 °C); before reconstitution refrigerate the lyophilized vaccine at 36 to 46 °F (2 to 8 °C); exposure to light may inactivate the vaccine viruses. The sterile diluent may be stored in the refrigerator or at room temperature (68 to 77 °F) and must not be frozen. ^[9]
• Priorix: store the lyophilized antigen vials refrigerated at 36 to 46 °F (2 to 8 °C) and protect from light; the prefilled diluent syringes may be stored refrigerated or at controlled room temperature up to 77 °F (25 °C); do not freeze either component. ^[7]

Contraindications and precautions

The Priorix label lists as contraindications a severe allergic reaction to any component or after a previous dose of any measles, mumps and rubella virus-containing vaccine, severe immunodeficiency, and pregnancy; the M-M-R II and ProQuad labels additionally list moderate or severe febrile illness and active untreated tuberculosis; the Varivax label lists severe allergic reaction to a component (including neomycin and gelatin) or a previous dose, immunosuppression, moderate or severe febrile illness, active untreated tuberculosis, and pregnancy. ^{[7] [9] [11] [13]}

CDC's appendix lists moderate or severe acute illness with or without fever as a precaution, whereas the M-M-R II, ProQuad and Varivax labels list moderate or severe febrile illness as a contraindication; the two sources classify the same condition differently. ^{[21] [9]}

Safety and adverse events

CDC's VIS says sore arm or redness where the shot is given, fever and a mild rash can happen after MMR; swelling of glands in the cheeks or neck, and temporary joint pain and stiffness (mostly in teenage or adult women) sometimes occur; seizures (often associated with fever) or a temporary low platelet count are rare, and in people with serious immune system problems the vaccine may cause a life-threatening infection. ^[2]

Priorix solicited reactions in trials: at 12 through 15 months, pain (26%), redness (25%), irritability (63%), loss of appetite (45%), drowsiness (45%) and fever (35%); at 4 through 6 years, pain (41%), redness (22%), swelling (11%), loss of appetite (21%), drowsiness (27%) and fever (24%); at 7 years and older, pain (12%) and redness (12%). ^[7]

Febrile seizures: the Priorix label warns of a risk of febrile seizure; ProQuad dose 1 in children 12 to 23 months who have not previously been vaccinated or had the wild-type infections is associated with higher rates of fever and febrile seizures 5 to 12 days after vaccination than M-M-R II and Varivax given separately, and caution is advised for those with an individual or family history of febrile seizures. ^{[7] [11]}

Thrombocytopenia: transient thrombocytopenia has been reported within 4 to 6 weeks following vaccination with measles, mumps and rubella vaccine, and the label advises weighing risk and benefit in children with thrombocytopenia or who had it after a previous dose. ^[11]

Varivax: frequently reported (10% or more) adverse reactions in children aged 1 to 12 years were fever of 102.0 °F (38.9 °C) or higher orally (14.7%) and injection-site complaints (19.3%); in adolescents and adults 13 years and older, fever of 100.0 °F (37.8 °C) or higher orally (10.2%) and injection-site complaints (24.4%); varicella-like rash (injection site or generalized) was also reported in all age groups. ^[13]

Vaccine virus transmission and salicylates: avoid close contact with high-risk individuals susceptible to varicella because of possible transmission of varicella vaccine virus, and avoid salicylates for 6 weeks after vaccination with ProQuad or Varivax; Reye syndrome has been reported in children and adolescents following use of salicylates during wild-type varicella infection. ^{[11] [13]}

Egg hypersensitivity: the M-M-R II and ProQuad labels advise caution in children with anaphylaxis or immediate hypersensitivity following egg ingestion; Syncope can occur with injectable vaccines including Priorix. ^{[9] [11] [7]}

Special populations

Pregnancy: MMR and varicella vaccines are contraindicated during pregnancy, and pregnancy should be avoided for 1 month after M-M-R II or Priorix and for 3 months after ProQuad or Varivax. ^{[7] [9] [11] [13]}

CDC adult notes: for pregnancy with no evidence of rubella immunity, MMR is contraindicated during pregnancy and 1 dose is given after pregnancy (before discharge from the health care facility); nonpregnant women of childbearing age with no evidence of rubella immunity get 1 dose; for pregnancy with no evidence of varicella immunity, varicella vaccine is contraindicated during pregnancy and doses are given after pregnancy before discharge. ^[16]

HIV: MMR is recommended (2 doses 28 days apart) for people 12 months and older with HIV who lack presumptive evidence of immunity and severe immunosuppression, defined as CD4 percentages of 15% or more for 6 months or more in those aged 5 years or younger, and CD4 percentages of 15% or more and CD4 count of 200 lymphocytes/mm3 or more for 6 months or more in older persons. For varicella, adults with HIV and CD4 percentage 15% or more and count 200 or more with no evidence of immunity may be vaccinated (2 doses 3 months apart), and varicella vaccine is contraindicated if CD4 percentage is below 15% or the count below 200. ^{[15] [16]}

Healthcare personnel: those born in 1957 or later without presumptive evidence of immunity should complete a 2-dose MMR series at least 4 weeks apart (or at least 1 dose for rubella); those born before 1957 with no evidence of immunity may be considered for 2 doses; healthcare personnel with no evidence of varicella immunity need a 2-dose series 4 to 8 weeks apart if previously unvaccinated, or 1 dose if they had 1 dose. ^[16]

Immunocompromised patients: do not give Priorix to individuals who are immunodeficient or immunosuppressed due to disease or medical therapy because of the risk of disseminated vaccine virus infection, and evaluate immune competence before giving M-M-R II, ProQuad or Varivax if there is a family history of congenital or hereditary immunodeficiency. ^{[7] [9]}

Counseling pearls for the pharmacy counter

• Children need 2 doses of MMR vaccine, usually at age 12 through 15 months and 4 through 6 years; most people vaccinated with MMR will be protected for life. ^[2]
• Infants traveling outside the United States when they are 6 through 11 months old should get a dose of MMR before travel and still need 2 additional doses at the recommended ages. ^[2]
• Tell the provider about pregnancy or possible pregnancy (pregnant women should not get MMR or varicella vaccine), a weakened immune system or a family history of hereditary or congenital immune problems, easy bruising or bleeding (MMR), and recent blood products or other vaccines in the past 4 weeks. ^{[2] [22]}
• Varicella vaccine: tell the provider about salicylate (aspirin) use and tuberculosis; MMR and varicella vaccines may be given at the same time as other vaccines, and children 12 months through 12 years might receive them together in one shot as MMRV. ^{[22] [2]}
• Counsel on signs of a severe allergic reaction (hives, swelling of the face and throat, difficulty breathing, a fast heartbeat, dizziness or weakness): call 9-1-1; and on avoiding pregnancy for 1 month after MMR (3 months after varicella-containing vaccines). ^{[2] [9] [13]}

Common patient questions

References

1. Centers for Disease Control and Prevention. Clinical overview of measles. Page dated August 5, 2026. Accessed October 11, 2026. https://www.cdc.gov/measles/hcp/clinical-overview/index.html. Accessed October 11, 2026.
2. Centers for Disease Control and Prevention. MMR (measles, mumps, and rubella) vaccine: what you need to know. Vaccine Information Statement, January 31, 2025. Accessed October 11, 2026. https://www.cdc.gov/vaccines/hcp/current-vis/mmr.html. Accessed October 11, 2026.
3. Centers for Disease Control and Prevention. Clinical overview of varicella (chickenpox). Page dated July 15, 2024. Accessed October 11, 2026. https://www.cdc.gov/chickenpox/hcp/clinical-overview/index.html. Accessed October 11, 2026.
4. Centers for Disease Control and Prevention. Measles vaccine recommendations (information for healthcare professionals). Page dated March 3, 2026. Accessed October 11, 2026. https://www.cdc.gov/measles/hcp/vaccine-considerations/index.html. Accessed October 11, 2026.
5. Centers for Disease Control and Prevention. Varicella vaccine recommendations (information for healthcare professionals). Page dated July 15, 2024. Accessed October 11, 2026. https://www.cdc.gov/chickenpox/hcp/vaccine-considerations/index.html. Accessed October 11, 2026.
6. U.S. Food and Drug Administration. PRIORIX product page (content current as of 03/30/2026). Accessed October 11, 2026. https://www.fda.gov/vaccines-blood-biologics/priorix. Accessed October 11, 2026.
7. PRIORIX (measles, mumps, and rubella vaccine, live) for injectable suspension, for subcutaneous use: prescribing information, revised 3/2026. GlaxoSmithKline Biologicals SA. U.S. Food and Drug Administration. Accessed October 11, 2026. https://www.fda.gov/media/189623/download?attachment. Accessed October 11, 2026.
8. U.S. Food and Drug Administration. Measles, mumps, and rubella virus vaccine live (M-M-R II) product page (content current as of 11/07/2025). Accessed October 11, 2026. https://www.fda.gov/vaccines-blood-biologics/vaccines/measles-mumps-and-rubella-virus-vaccine-live. Accessed October 11, 2026.
9. M-M-R II (measles, mumps, and rubella virus vaccine live) for injectable suspension, for intramuscular or subcutaneous use: prescribing information, revised 11/2025. Merck Sharp & Dohme LLC. U.S. Food and Drug Administration. Accessed October 11, 2026. https://www.fda.gov/media/75191/download?attachment. Accessed October 11, 2026.
10. U.S. Food and Drug Administration. ProQuad product page (content current as of 11/07/2025). Accessed October 11, 2026. https://www.fda.gov/vaccines-blood-biologics/vaccines/proquad. Accessed October 11, 2026.
11. ProQuad (measles, mumps, rubella and varicella virus vaccine live) for injectable suspension, for intramuscular or subcutaneous use: prescribing information, revised 11/2025. Merck Sharp & Dohme LLC. U.S. Food and Drug Administration. Accessed October 11, 2026. https://www.fda.gov/media/75195/download?attachment. Accessed October 11, 2026.
12. U.S. Food and Drug Administration. VARIVAX (refrigerated and frozen formulations) product page (content current as of 08/23/2023). Accessed October 11, 2026. https://www.fda.gov/vaccines-blood-biologics/vaccines/varivax-refrigerated-and-frozen-formulations. Accessed October 11, 2026.
13. VARIVAX (varicella virus vaccine live), suspension for intramuscular or subcutaneous injection: prescribing information, revised 08/2023. Merck Sharp & Dohme LLC. U.S. Food and Drug Administration. Accessed October 11, 2026. https://www.fda.gov/media/76008/download?attachment. Accessed October 11, 2026.
14. Centers for Disease Control and Prevention. Child and adolescent immunization schedule notes: recommendations for ages 18 years or younger, United States, 2025. July 2, 2025. Accessed October 11, 2026. https://www.cdc.gov/vaccines/hcp/imz-schedules/child-adolescent-notes.html. Accessed October 11, 2026.
15. Centers for Disease Control and Prevention. Measles vaccination for specific groups. Page dated July 15, 2024. Accessed October 11, 2026. https://www.cdc.gov/measles/hcp/vaccine-considerations/specific-groups.html. Accessed October 11, 2026.
16. Centers for Disease Control and Prevention. Adult immunization schedule notes: recommendations for ages 19 years or older, United States, 2025. July 2, 2025. Accessed October 11, 2026. https://www.cdc.gov/vaccines/hcp/imz-schedules/adult-notes.html. Accessed October 11, 2026.
17. Centers for Disease Control and Prevention. CDC acts on Presidential Memorandum to update childhood immunization schedule. News release, January 5, 2026. Accessed October 11, 2026. https://www.cdc.gov/media/releases/2026/2026-cdc-acts-on-presidential-memorandum-to-update-childhood-immunization-schedule.html. Accessed October 11, 2026.
18. Congressional Research Service. The 2026 Childhood Immunization Schedule (R48982). June 11, 2026. Accessed October 11, 2026. https://www.congress.gov/crs_external_products/R/PDF/R48982/R48982.1.pdf. Accessed October 11, 2026.
19. Centers for Disease Control and Prevention. Healthcare professionals: immunization schedules. Accessed October 11, 2026. https://www.cdc.gov/vaccines/hcp/imz-schedules/index.html. Accessed October 11, 2026.
20. American Academy of Pediatrics. AAP releases recommended childhood and adolescent immunization schedule for 2026. HealthyChildren.org news. Accessed October 11, 2026. https://healthychildren.org/English/news/Pages/AAPs-recommended-childhood-and-adolescent-immunization-schedule-for-2026.aspx. Accessed October 11, 2026.
21. Centers for Disease Control and Prevention. Child and adolescent immunization schedule appendix: guide to contraindications and precautions (July 2, 2025 edition). Accessed October 11, 2026. https://www.cdc.gov/vaccines/hcp/imz-schedules/child-adolescent-appendix.html. Accessed October 11, 2026.
22. Centers for Disease Control and Prevention. Varicella (chickenpox) vaccine: what you need to know. Vaccine Information Statement. Accessed October 11, 2026. https://www.cdc.gov/vaccines/hcp/current-vis/varicella.html. Accessed October 11, 2026.