98.7 is not a fever in most cases, including in babies. A fever in babies is generally considered a temperature of 100.4°F or higher.
When checking a baby’s temperature, the method used matters. Rectal temperatures are usually the most accurate for infants, while underarm readings can be less precise and may be slightly lower.
Call a pediatrician right away if your baby is 3 months old or younger and has a rectal temperature of 100.4°F or higher, or if they have symptoms like unusual sleepiness, poor feeding, persistent crying, trouble breathing, vomiting, or signs of dehydration.