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MMRV Vaccine

The 4-6 year dose — measles, mumps, rubella, and varicella combined (Priorix-Tetra® or ProQuad®)

Quick Summary

MMRV Vaccine (4–6 years)

Combines four protections — measles, mumps, rubella, and varicella — in one injection.

Required for school Publicly funded
Diseases Protected Against
Measles, mumps, rubella, and varicella (chickenpox)
Ontario Routine Timing
One dose between 4 and 6 years of age (before starting school)
Number of Doses
This is the second dose of measles/mumps/rubella and varicella protection
Publicly Funded Status
Yes — provided free of charge as part of Ontario's routine schedule
Bottom line: MMRV combines the second dose of MMR with the second dose of varicella into a single injection at 4–6 years. Measles, mumps, and rubella are required for school, and varicella is required for children born in 2010 or later (unless a valid exemption applies).
The Diseases

What it protects against

MMRV combines protection against four diseases. For full detail on each, see the MMR and varicella profiles; here's a summary.

Disease What parents might notice How it spreads Why it can be serious How vaccination helps
Measles High fever, cough, runny nose, red eyes, then a blotchy rash. Through the air — one of the most contagious diseases known. Can cause pneumonia or, less commonly, brain swelling; more dangerous in young children. Two doses provide strong, lasting protection.
Mumps Fever, headache, and swollen, puffy cheeks/jaw. Saliva and respiratory droplets. Can cause inflammation of glands, the brain's lining, and rarely hearing loss. Vaccination reduces the chance and severity of mumps.
Rubella Often mild — low fever and a rash. Coughing, sneezing, and close contact. Most dangerous in pregnancy, where it can cause serious birth defects. Protecting children helps protect pregnancies in the community. Vaccination prevents rubella and its spread.
Varicella (chickenpox) An itchy blister rash all over the body, usually with fever. Extremely contagious — through the air and contact with blisters. Usually mild but can cause skin infections, pneumonia, or more serious problems; dangerous for vulnerable people. The second dose strengthens protection and reduces "breakthrough" chickenpox.
This is a second dose of protection against all four diseases — the first doses were the MMR at 12 months and varicella at 15 months. Combining them into MMRV means one injection instead of two at this visit.
Timing & Schedule

Why it's given at this age

Why at 4–6 years? This is the second dose of measles/mumps/rubella and varicella protection, timed before school entry. A second dose improves and lengthens protection — especially for measles and varicella, where a single dose doesn't fully protect everyone.

Why combine them? Since both the MMR second dose and the varicella second dose are due around the same age, combining them into MMRV means one injection instead of two — fewer needles for your child at the same visit.

What if it's late? A delay doesn't mean restarting. The dose can generally be given at the next opportunity, following minimum spacing from the earlier doses. A healthcare provider or public health unit can confirm timing. See the Catch-Up & Missing Records page.

Can it be given with other vaccines? Yes. At the 4–6 year visit it's routinely given alongside the Tdap-IPV booster, at a different injection site.

A note on MMRV and febrile seizures: When the very first dose of measles/varicella protection is given as a combined MMRV (rather than separate MMR and varicella shots) in younger children, there's a small increased chance of a fever-related (febrile) seizure. This is part of why Ontario gives the first doses separately (MMR at 12 months, varicella at 15 months) and uses the combined MMRV for the second dose at 4–6 years, when this consideration is less of a factor.
Ontario School & Reporting Status

School and reporting status

All four diseases in MMRV relate to Ontario's school requirements. Under the Immunization of School Pupils Act (ISPA), measles, mumps, and rubella are required for school attendance, and varicella is required for children born in 2010 or later — unless a valid medical or non-medical exemption is on file. MMRV provides the second dose of protection against all four.

Because this dose falls right around school entry, it's one that public health pays close attention to when reviewing records. Making sure it's given and reported helps keep your child's record complete.

Reporting: As with all vaccines, parents and caregivers are generally responsible for reporting their child's immunizations to their local public health unit, since healthcare providers do not always do this automatically. Make sure the dose is recorded on the immunization record (the "yellow card") and reported — for example, through Immunization Connect Ontario (ICON) if your area uses it.

Exemptions: If your child cannot receive this vaccine for medical reasons, or you are seeking a non-medical exemption, see the School Requirements hub for the process.

Ingredient Transparency

What's in this vaccine

Two MMRV products are used in Canada: Priorix-Tetra® (GSK) and ProQuad® (Merck). Either may be used depending on supply. Both are live attenuated vaccines (weakened viruses that can't cause the diseases in healthy people). The information below reflects their Health Canada product monographs.

Ingredient / Component Category Why it's there Plain-English explanation
Live attenuated measles, mumps, rubella, and varicella viruses Active ingredients Weakened forms of the four viruses that train the immune system. "Attenuated" means weakened — enough to prompt protection without causing the diseases in healthy people.
Amino acids Stabilizer Help keep the vaccine stable. The building blocks of proteins, found throughout the body and in food.
Sugars and sugar alcohols (e.g. sucrose, sorbitol, mannitol, lactose) Stabilizers Protect the vaccine viruses and keep the product stable, especially during freeze-drying. Sugars used as stabilizers, similar to those in many foods and medicines.
Gelatin (in some products) Stabilizer / potential allergen Helps protect the vaccine viruses. Used as a stabilizer in some live vaccines. Relevant for anyone with a known severe gelatin allergy.
Neomycin (trace amounts) Manufacturing process residual (antibiotic) Used during manufacturing to help prevent bacterial contamination. A trace amount may remain; relevant for those with a known severe neomycin allergy.
Water for injection (diluent) Diluent Used to reconstitute the freeze-dried vaccine before injection. Sterile water used to mix the vaccine just before it's given.
About egg allergy: The measles and mumps components are grown using chick-embryo cell cultures. Major medical bodies note MMR/MMRV can generally be given to children with egg allergy, as the egg protein amount is negligible. For severe egg allergy or a history of severe allergic reactions, discuss with a provider.
About aspirin after vaccination: Because of the varicella component, avoid ASA (Aspirin) and salicylate-containing products for a period after this vaccine in children and teens (due to a rare condition, Reye's syndrome). Acetaminophen or ibuprofen can be used instead.
Side Effects & Safety

Side effects and safety

Expected / common side effects

  • Soreness, redness, or swelling where the needle was given
  • Mild fever
  • A mild rash — sometimes measles-like, sometimes a few chickenpox-like spots
  • Temporary swelling of glands in the cheeks or neck
  • Fussiness or tiredness

Timing and duration: Because MMRV is a live vaccine, some reactions — like a mild fever or rash — can appear a week or two after the dose, as the immune system responds. They're usually mild and pass on their own.

About fever: Fever is somewhat more common after a measles-containing vaccine. For the combined MMRV given as a first dose in younger children, this slightly raises the chance of a fever-related (febrile) seizure — which is part of why Ontario uses separate MMR and varicella shots for the first doses and the combined MMRV for the second dose at 4–6 years.

Home care: Acetaminophen or ibuprofen may be used for discomfort or fever. Avoid ASA (Aspirin) and salicylate-containing products for a period after this vaccine in children and teens (see ingredients note).

Many children have no side effects at all, and that does not mean the vaccine didn't work.

Rare but important

  • Severe allergic reaction (anaphylaxis) — reported rarely after vaccination in general; exact frequency varies by source.
  • Febrile seizure — a seizure triggered by fever, which can happen with any fever-causing illness or vaccine. Uncommon and usually brief.
  • Spread of vaccine virus — rarely, the weakened vaccine virus can pass from a vaccinated person who develops a rash to a susceptible close contact. This is uncommon and the resulting illness is usually mild.

What clinics do to reduce risk: Clinics ask about allergy history and immune-system conditions before vaccination and are equipped with epinephrine and trained staff in case of a severe allergic reaction.

Observation period: Many clinics recommend staying nearby for about 15 minutes after vaccination, as severe allergic reactions — though rare — typically occur shortly after the injection.

Get urgent help now if your child has:

  • Trouble breathing
  • Swelling of the lips, tongue, throat, or face
  • Widespread hives together with breathing difficulty
  • Severe weakness, limpness, or unresponsiveness
  • A seizure
  • Persistent, inconsolable crying that won't settle, or you are very worried
  • A high or persistent fever, especially in a young infant
  • Any symptom that feels serious or is rapidly getting worse

If any of these occur, go to the nearest emergency department or call 911. Otherwise, contact a healthcare provider and let them know what happened — this information also helps with vaccine safety monitoring.

Before the Appointment

Who should pause or speak with a healthcare provider first

Speak with a healthcare provider before this vaccine if:

  • Your child has had a serious allergic reaction to a previous dose of varicella vaccine, or to any of its components (including neomycin or gelatin)
  • Your child has a weakened immune system — for example, due to certain medical conditions or treatments like chemotherapy or high-dose steroids. As a live vaccine, varicella may not be recommended, or may need specialist input
  • Your child is pregnant (relevant for adolescents) — varicella vaccine is not given during pregnancy
  • Your child has recently received blood products or immune globulin — this can affect how well a live vaccine works, so timing may need adjusting
  • Your child has a moderate or severe acute illness (it's generally fine to wait until they feel better)

These usually do NOT require delaying this vaccine:

  • A mild cold or other minor illness without fever
  • Currently breastfeeding
  • A stable, ongoing chronic health condition
  • Currently taking antibiotics for an unrelated condition
  • A household member who is pregnant or has young children (precautions apply only in the rare case of a post-vaccine rash)
Common Questions

Questions parents often ask

Yes. At the 15-month visit, varicella may be given alongside other scheduled vaccines. As a live vaccine, it has specific timing rules relative to other live vaccines (like MMR) — they're either given together or spaced apart by a minimum interval, which a healthcare provider manages.
Being behind does not mean starting the series over. The remaining doses can generally be given following minimum spacing guidelines. Visit the Catch-Up & Missing Records page, or speak with a healthcare provider to confirm the right plan for your child.
Generally, no. A mild cold without fever is usually not a reason to delay. If your child has a fever or seems more unwell, it's reasonable to mention this to the clinic — they can advise whether to proceed or reschedule.
Giving the combined MMRV as a first dose in younger children slightly raises the chance of a fever-related (febrile) seizure. So Ontario gives the first doses separately (MMR at 12 months, varicella at 15 months) and uses the combined MMRV for the second dose at 4–6 years, when this is less of a concern — and when combining means one needle instead of two.
They still need the measles, mumps, and rubella protection in MMRV. If your child has had chickenpox, the varicella part may not be necessary — but a provider can advise on the best option (for example, a separate MMR dose). Don't skip the dose without checking, since the MMR components are still needed.
This is common and manageable. Gather whatever records you have, and contact your local public health unit or healthcare provider — they can often help locate or reconstruct records, or advise on next steps if records truly cannot be found. See the Catch-Up & Missing Records page.
This vaccine is typically given by a family doctor or nurse practitioner as part of routine infant well-child visits. Some public health units also offer immunization clinics. See the Resources page for links to find services in your area.
Parents and caregivers are generally responsible for reporting vaccines to their local public health unit — healthcare providers do not always do this automatically. Many areas use Immunization Connect Ontario (ICON) for this. See the Resources page for links.
Mild soreness, redness, fussiness, or a low fever for a day or two are common and expected. Review the "Get urgent help now" list above — if any of those signs occur, seek urgent care. Otherwise, contact a healthcare provider with any concerns.
What the Evidence Shows

What we know about the second dose

Fact For measles and varicella in particular, one dose protects most children but not all — a second dose closes that gap and provides stronger, more lasting protection.
Concern Some parents wonder whether a second dose is really necessary if their child already had the first doses and seems protected.
Evidence A small percentage of children don't respond fully to the first dose of measles or varicella vaccine. The second dose protects those children and strengthens protection overall. After two doses, protection against measles in particular is very high. This is why the schedule includes a routine second dose, conveniently combined here as MMRV.
Takeaway The second dose isn't redundant — it meaningfully improves protection, especially for measles and varicella, and completes the recommended series.
Fact Combining four protections into one injection (MMRV) is well studied and means fewer needles at the 4–6 year visit.
Concern Some parents worry that a combined four-in-one vaccine is "too much at once."
Evidence Combination vaccines are tested as a combined product before approval, and a child's immune system readily handles the components together — far fewer than the many germs encountered in daily life. The main known consideration with MMRV (a slightly higher chance of febrile seizure when used as a first dose in young children) is specifically why Ontario reserves the combined product for the second dose at 4–6 years.
Takeaway Using the combined MMRV for the second dose is a deliberate, evidence-based choice that reduces needles while keeping the febrile-seizure consideration in mind.
Ontario Next Steps

What to do next

Where to get it

Typically given by a family doctor or nurse practitioner during routine well-child visits. Some public health units also offer clinics.

What to bring

Your child's immunization record (the "yellow card"), health card if available, and a list of any allergies or previous reactions.

If you're behind

Catching up does not mean restarting. Visit the Catch-Up & Missing Records page or ask your provider for a review.

If records are missing

Contact your local public health unit — they may have records on file, or can advise on next steps.

If vaccinated outside Ontario

Bring any available records to a healthcare provider for review — products and schedules elsewhere may differ slightly from Ontario's.

Contact public health

For record reporting, school requirements, or general questions, see the Resources page for your local public health unit's contact details.

Sources

Where this information comes from

This page is based on:

Last reviewed: June 2026  ·  Next review due: December 2026
Schedules, products, and eligibility can change. Always confirm current details with your healthcare provider, your local public health unit, or official Ontario sources.

Please note: This is an independent website. It is not affiliated with, endorsed by, or operated by the Government of Ontario, the Ministry of Health, or any public health unit. The information here is for general education only and is not medical advice — always consult a licensed healthcare provider about your or your child's immunizations.