Measles vaccine !
Live attenuated measles virus, given as MMR (triple viral, with mumps and rubella) or MR. Two doses protect almost everyone.
Updated 2026-11-01
Also called: MMR (measles, mumps, rubella; triple viral), MR (measles-rubella), MMRV (with varicella)
The figure shows the measles virus H protein, which binds the cell receptor; the live vaccine strain induces neutralising antibodies against H and the fusion protein F.
Mechanism of action
The vaccine virus replicates weakly after injection and induces antibodies and cellular immunity similar to natural infection, without the disease. Measles has a single antigenic type, so one vaccine protects against all circulating strains. Most children seroconvert after the first dose and nearly all after the second; the second dose catches those who did not respond to the first.
- Attenuated measles virus is injected and replicates weakly
- Antibodies form against the H and F proteins
- Cellular immunity and memory develop as in natural infection
- The second dose covers children who did not respond to the first
Pharmacokinetics
- Onset and duration
- About 95% seroconvert after the first dose and more than 99% after two
Indications
- Routine childhood prevention of measles as MMR (triple viral)
- Colombia (MinSalud, measles alert): children aged 1 to 10 should have two doses of triple viral, with the second at 18 months; health and tourism workers and international travellers check their status
Adverse effects
Common
- Fever after the dose
- Transient rash
- Arthralgia, mainly in adult women (rubella component)
Contraindications
- Pregnancy
- Severe immunosuppression, including high-dose systemic corticosteroids for two weeks or more
- Severe allergic reaction to a previous dose or a component (gelatin, neomycin)
Key interactions
- Antibody-containing blood products (immunoglobulins, transfusions)
- Antibodies neutralise the vaccine virus: vaccination is delayed for months after them
- Tuberculin skin test
- The vaccine can blunt the reaction: the test is done the same day or delayed after vaccination
- Yellow fever vaccine
- Given together, responses to some antigens are lower; when possible they are separated by one month
What is monitored
- Two documented doses
- Fever and rash after the dose; history of thrombocytopenia
Administration and safety
- Lyophilised: reconstitute only with the diluent supplied
- Subcutaneous route
- Do not confuse MMR (triple viral) with MR (measles-rubella) or MMRV: check the vial
- Record the batch and product
Nursing care
- Ask about pregnancy, immunosuppression and recent immunoglobulins or transfusions
- Warn the family about possible fever and rash after the dose
- Advise women to avoid pregnancy for four weeks after vaccination
- Egg allergy is not a reason to withhold it
Pregnancy and breastfeeding
Contraindicated in pregnancy, and pregnancy is avoided for four weeks after vaccination; inadvertent vaccination is not a reason to end a pregnancy.
Test yourself
Think of the answer, then tap the question to see it.
Why is a second dose of MMR given?
A small proportion of children do not respond to the first dose; the second dose protects almost all of them.
Why is MMR delayed after immunoglobulin or a transfusion?
The passive antibodies neutralise the live vaccine virus and prevent a response.
Is egg allergy a contraindication to MMR?
No: it can be given without skin testing or special protocols.
Related drugs
← Back to the class: Viral vaccines
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Chapter 13: Measles | Pink Book | CDC (Centers for Disease Control and Prevention, 2021); Lineamiento Técnico y Operativo de la Primera Jornada Nacional de Vacunación (Ministerio de Salud y Protección Social (Colombia), 2026); Yellow Fever | CDC Yellow Book™ (Centers for Disease Control and Prevention, 2025); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.