Passive Immunization
A person may become immune to a specific disease in several ways. For some illnesses, such as measles and chickenpox, having the disease usually leads to lifelong immunity to it. Vaccination is another way to become immune to a disease. Both ways of gaining immunity, either from having an illness or from vaccination, are examples ofactive immunity. Active immunity results when a person’s immune system works to produce antibodies and activate other immune cells to certain pathogens. If the person encounters that pathogen again, long-lasting immune cells specific to it will already be primed to fight it.
A different type of immunity, called passive immunity, results when a person is given someone else’s antibodies. When these antibodies are introduced into the person’s body, the “loaned” antibodies help prevent or fight certain infectious diseases. The protection offered by passive immunization is short-lived, usually lasting only a few weeks or months. But it helps protect right away.
埃博拉疫情肆虐西非，两名在利比里亚工作的美国人感染病毒后目前正在接受治疗。据香港《东方日报》8月1日报道，面对仅有一人份的血清，染病医生果断决定将血清让与女传教士。
染病的两名美国人分别是医生布兰特利及女传教士里特博尔。布兰特利所工作的慈善组织于31日发声明，指治疗埃博拉的试验性血清运虽然抵利比里亚，然而份量只足够一人使用。
布兰特利随后表示，要将血清用于染病的里特博尔身上；而他则接受一名14岁男童的输血。该名男童埃博拉病毒后痊愈，也曾受到布兰特利的照顾。
埃博拉病毒新一波疫情最初于今年3月爆发于几内亚，随后迅速向利比里亚与塞拉利昂扩散。世界卫生组织统计称，截止7月29日，埃博拉病毒已导致672人死亡。
