What should you know about yellow fever vaccine diarrhea?

Loose stools can happen around the time of a vaccination for reasons unrelated to the injection, including a food-borne illness, another infection, a change in diet, or travel. Note when the diarrhea began, how often it occurs, and whether you also have fever, vomiting, abdominal pain, rash, or dizziness.

Yellow fever vaccine reactions deserve particular attention when symptoms are intense, unusual, or affect more than one body system. A clinician can assess the timing, your medical history, and other possible causes rather than assuming the vaccine is responsible.

Drink frequent small amounts of safe fluids and continue light foods as tolerated. Rest and avoid alcohol while you feel unwell. Do not use an anti-diarrheal medicine if you have blood in your stool or a high fever unless a clinician advises it.

Write down the vaccine date, the onset of symptoms, medicines or supplements taken, recent meals, and travel exposures. This record gives a healthcare professional useful details if your symptoms continue or worsen.

Get urgent care for trouble breathing, swelling of the face or throat, widespread hives, confusion, fainting, severe weakness, or signs of dehydration such as very little urine. Contact a clinician promptly for bloody stools, persistent vomiting, severe abdominal pain, fever with worsening illness, or diarrhea that is not improving.

Ask whether your symptoms need testing for infection or dehydration, which fluids are suitable for you, and whether any current medicine should be paused. If you are due to travel, ask whether your condition changes the safest timing for departure.