A fever in a child is generally defined as a body temperature above 100.4°F (38°C). A temperature of 99.8°F (37.7°C) is slightly elevated, but it is not considered a fever in a child. However, it is important to keep in mind that the interpretation of a child’s temperature can depend on a variety of factors, such as their age, overall health, and other symptoms they may be experiencing. If you are concerned about your child’s health, it is always a good idea to consult with a healthcare professional.