My 2 month old has a fever. do i need to take them to a doctor?

What the evidence says

Yes, take your baby to be checked. For babies younger than 3 months old, any fever is treated as urgent, even if the baby is feeding, sleeping and acting normally otherwise.

This is because a fever, a body temperature of 38.0°C (100.4°F) or higher measured rectally, can be the only clue that something serious is going on. Young babies' immune systems are still immature, and they cannot fight some infections as well as older children.

A Canadian Paediatric Society guideline on well infants with fever up to 90 days old found that while most have a mild viral illness, a meaningful share turn out to have a serious bacterial infection like a urinary tract infection, infection in the blood, or meningitis, an infection around the brain and spinal cord. Doctors cannot always tell just by looking whether a baby falls into that higher risk group, which is why urgent evaluation and sometimes tests are recommended for every young febrile infant.

Canadian guidance from Caring for Kids is direct on this point: babies under 3 months old with a fever should be seen urgently, and babies under 6 months should see a doctor whenever they run a fever. This matches American Academy of Pediatrics guidance for infants 8 to 60 days old with fever.

Do not give your baby ibuprofen before checking with a doctor, and always check with your doctor first before giving any fever medicine to a baby under 3 months. Go to an emergency department or call your doctor right away rather than waiting to see if the fever passes on its own.