What should you know about vaccination during fever?

Fever is a sign that the body is responding to infection or another process. A healthcare professional considers the temperature, the person’s age, other symptoms, overall alertness, and the vaccine planned. The concern is usually the current illness and the chance of confusing its symptoms with a vaccine reaction, rather than the vaccine being unable to work.

A runny nose or mild cough without significant fever may not require a delay. Fever with poor feeding, breathing difficulty, a widespread rash, or unusual sleepiness needs assessment. Illnesses such as a common cold, acute bronchitis, bronchiolitis, chickenpox, or COVID-19 can have different implications, so the diagnosis matters.

Call the vaccination clinic before attending and describe the temperature, symptoms, age, and any recent medicines. Do not give fever-reducing medicine solely to conceal illness before an appointment unless a clinician advises it. Keep fluids available and follow the care plan for the suspected illness.

If vaccination is postponed, ask when to rebook and record which dose is pending. Avoid close contact with vulnerable people when an infectious illness is suspected, and follow local advice about testing or staying home.

Seek urgent help for severe breathing difficulty, a seizure, a stiff neck, confusion, blue lips, signs of dehydration, or a child who is difficult to wake. Prompt medical advice is also appropriate when fever is worsening, lasts longer than expected, or occurs in a very young baby. After vaccination, urgent symptoms include facial swelling, wheezing, collapse, or widespread hives.

Ask whether the current fever should delay the dose, what symptoms would change that decision, and how quickly to rebook. Confirm which fever-care measures are suitable, whether an infectious condition is suspected, and how to protect people at home.