免疫学是预防疾病的一个重要方面。英国在对一些疾病实施免疫前,由于社会条件的改善,很多传染病已经消失。约在150年前,英国每年有2,000名儿童死于猩红热,1,000～2,000名儿童死于白喉。到1940年时,仅少数儿童死于这些病.这不仅是由于预防接种的缘故,更主要是因为改善了生活条件,如:营养、住房和消灭昆虫等.特别是国家工业化后,家庭成员减少,有利于控制疾病的传播。 Immunology is an important aspect of disease prevention. Before the immunization of some diseases in the UK, many infectious diseases have disappeared due to the improvement of social conditions. About 150 years ago, 2,000 children a year died of scarlet fever and 1,000 to 2,000 children died of diphtheria in Britain. By 1940, only a few children died of these diseases, not only because of vaccination, but mainly because of improved living conditions such as nutrition, shelter and the elimination of insects, etc. In particular, after the industrialization of the country, the number of family members decreased , Is conducive to controlling the spread of the disease.