The latency period differs from person to person. Twu Shiing Jer notes that whether symptoms appear early or late is determined by many different factors, including the virulence and quantity of the virus, the strength of the patient's resistance, whether they are receiving treatment, whether they have a balanced nutritional intake, a regular lifestyle and regular exercise, and how much stress is present in their lives.
每個感染者發病的時間不同，塗醒哲指出，發病早晚與感染病毒的毒性、量的多寡，感染者的抵抗力，是否接受治療，飲食是否均衡營養、生活是否規律，有無持續運動，生活壓力大小… … 等，都有關係。