When fever episodes are severe, patients may also experience chills, which is an involuntary contraction of the muscles meant to turn energy into heat. The immune response triggered by coronavirus reaches the brain receptors, and this organ starts releasing signals to other parts of the body to maintain and create heat in order to counter the pathogens.
In the muscle tissue, this causes involuntary muscle contractions, which patients perceive as chills. They are usually associated with sweating during the peak of fever, and right before the temperature falls down.
Chills are usually found in later stages of the disease, and it is not a typical early sign of coronavirus.