Can a baby's viral fever above 39°C cause brain damage?

Fever, also known as pyrexia, generally does not cause brain damage in infants with viral fever reaching 39°C.

Fever is the body's immune response against invading viruses or bacteria. It helps eliminate pathogens and promotes the development of an infant's immune system. Under normal circumstances, a fever of 39°C in infants does not harm the brain. Only extremely high fevers or cases involving central nervous system infections may affect the nervous system and lead to brain damage.

Brain damage may occur when body temperature exceeds 41°C, causing denaturation of brain proteins and injury to brain cells. Additionally, certain brain inflammations—such as purulent meningitis or encephalitis B—can also damage brain cells. If brain infections are not treated promptly, they can worsen and lead to severe neurological complications. A high fever of 39°C alone does not damage the brain, but if it persists for too long or rises too rapidly, it may trigger abnormal electrical discharges in brain cells, leading to febrile seizures or secondary epilepsy.

During treatment, dietary management is recommended. Infants should be given light, easily digestible foods, while intake of meat, fish, and shellfish should be reduced.