White blood cells also make chemicals that cause a fever. A fever is a higher-than-normal body temperature. Normal human body temperature is 98.6°F (37°C). Most bacteria and viruses that infect people reproduce fastest at this temperature. When the temperature is higher, the pathogens cannot reproduce as fast, so the body raises the temperature to kill them. A fever also causes the immune system to make more white blood cells. In these ways, a fever helps the body fight infection.
Ben was feeling tired and ache all day so he decided to go to bed. When Ben woke  up he felt even worse and his head felt hot. Ben went to the doctor who told him he had a virus that had caused a fever and he should get plenty of rest.
Did Ben have more or less white blood cells?