What should you know about measles side effects?

After the combined measles, mumps and rubella vaccine, the injection site may feel sore, red or swollen. Some people feel tired or develop a mild fever. A light rash or swollen glands can appear later as the immune system responds. These reactions usually settle without special treatment.

A vaccine reaction is different from measles infection. The vaccine cannot cause measles, although a rash or fever can be unsettling. The timing, severity and other symptoms help a clinician decide whether the illness is related to vaccination or has another cause.

Offer rest and fluids, keep clothing loose around a sore injection site, and follow the vaccinator's advice about symptom relief. Do not give a child medicine unless it is suitable for the child and used according to professional or package guidance. Keep the vaccination record and note when symptoms started.

Tell a healthcare professional about a previous serious vaccine reaction or a new illness before another dose. Read [MMR Vaccination](/treatments/preventive-care-and-vaccination/mmr-vaccination/) for related information, and use [GP Consultation](/treatments/consultations-and-assessment/gp-consultation/) when an individual review is needed.

Seek emergency help for trouble breathing, swelling of the face or throat, collapse, or signs of a severe allergic reaction. Contact a clinician for a persistent or high fever, unusual drowsiness, repeated vomiting, a seizure, or a rash that is rapidly worsening. [Fever](/symptoms/fever/) and [Swollen Glands](/symptoms/swollen-glands/) explain symptoms that may also need assessment. A new exposure can warrant advice about [Measles](/conditions/measles/).

Ask which reactions are expected for this vaccine, how to relieve discomfort, how long to monitor symptoms, and which reaction should be reported urgently. If a rash or fever appears, ask whether its timing fits vaccination or whether another infection should be considered.