No, 38 degrees Celsius (100.4°F) is not considered a fever. Generally, a fever is considered to be a body temperature of 38°C (100.4°F) or higher. Depending on the individual and their age, a fever may be of greater concern in some cases than others.
In adults, a fever is generally considered to be a body temperature of over 38°C (100.4°F). For newborns, a temperature above 37.5°C (99.5°F) is considered a fever. In young children, a fever is generally considered to be a temperature over 38°C (100.4°F).
It is important to be aware of the symptoms that come with a fever, such as a headache, chills, a sore throat, and body aches. If these symptoms occur in conjunction with a fever, it is important to seek medical attention.
In summary, 38 degrees Celsius (100.4°F) is not a fever, but if accompanied by other symptoms, it is important to seek medical attention.