Fever 10 days after the MMR vaccine

MMR contains weakened forms of measles, mumps and rubella viruses. The immune system may respond after a delay, so fever and a light rash can appear several days after vaccination. This response is usually short-lived and is not the same as catching measles, mumps or rubella from the vaccine. Fever can also have an unrelated cause, such as a common cold, so consider cough, runny nose, vomiting, diarrhoea, pain and the child’s general behaviour.

Check the temperature with a reliable thermometer and note when it began. Offer frequent fluids, breastfeeds or formula, and allow rest without overdressing. Keep the child comfortable and follow the label or clinician’s advice for any fever medicine; use the child’s age and weight instructions rather than guessing. Do not give aspirin to children. Contact the vaccination provider if you are unsure which symptoms fit the expected response or if the fever is not settling.

Get urgent help if the child has trouble breathing, is difficult to wake, has a seizure, develops a purple or rapidly spreading rash, has signs of dehydration, or looks seriously unwell. Seek prompt advice for a very young infant with fever, a fever that persists, or symptoms that worsen rather than improve. Mention the vaccine date and any medicines given. If measles-like illness is possible, phone ahead before attending a clinic so staff can reduce exposure to others.

Ask whether the timing and symptoms fit a vaccine response; how often to check temperature; which medicine and dose are suitable; and when the child should be examined.