Grippe is an old fashioned word for the flu — the virus that can give you a fever, sore throat, and a headache. If you fear you're coming down with the grippe, you might spend the day in bed drinking tea.
When someone feels achy, shivery, and tired, they probably fear having the grippe, which is highly contagious and sickens many people each year, mostly in the winter months. Today it's more commonly called the flu, short for influenza. English speakers called it the grippe in the eighteenth century, from the French grippe, which means "influenza," but also "seizure," from gripper, "grasp or hook."