Conrad D A, Jenson H B
Department of Pediatrics, University of Texas Health Science Center, San Antonio 78284-7811, USA.
Postgrad Med. 1996 Oct;100(4):113-8, 121-5, 127. doi: 10.3810/pgm.1996.10.95.
The initial motives behind development of vaccines were to protect against life-threatening infections (eg, rabies, diphtheria), to eradicate sweeping outbreaks of serious diseases (eg, paralytic poliomyelitis, smallpox), and to prevent diseases in a vulnerable population by the immunization of surrogates (eg, rubella immunization to prevent congenital rubella syndrome). Now a fourth motive emerges: prevention of less serious infections to improve quality of life. The advantages of new vaccines and immunization programs should no longer be measured exclusively in terms of the number of lives saved but should take into account direct and indirect cost savings and overall benefit to individual and societal health and well-being. Although varicella and hepatitis A infections can be life-threatening, most cases are self-limited and have no significant sequelae. Immunization is more likely to improve quality of life than to save lives. Vaccination against typhoid remains a potentially lifesaving act in developing nations, but even the newer typhoid vaccines were developed primarily to reduce the frequency and severity of adverse reactions to immunization rather than to improve the protective efficacy of the original heat-phenol inactivated vaccine. Varicella virus vaccine, hepatitis A virus vaccines, and the typhoid polysaccharide Vi capsular vaccine represent important additions to immunization agents. These vaccines are immunogenic, clinically effective, and generally safe, with infrequent and usually mild adverse reactions. Their favorable benefit-risk ratio should encourage their appropriate use. The Centers for Disease Control and Prevention, the American Academy of Pediatrics, and the American Academy of Family Physicians have already recommended varicella vaccine for universal immunization of children. Formal recommendations that hepatitis A vaccine also be routinely used for all children may be forthcoming in the next few years; in the meantime, persons at high risk should be immunized. Typhoid vaccination will likely continue to be used selectively for those who have significant contact with the organism or those who travel to typhoid-endemic countries.
疫苗研发背后的最初动机是预防危及生命的感染（如狂犬病、白喉），根除严重疾病的大规模爆发（如麻痹性脊髓灰质炎、天花），以及通过对替代人群进行免疫来预防弱势群体中的疾病（如风疹免疫以预防先天性风疹综合征）。现在出现了第四个动机：预防不太严重的感染以提高生活质量。新疫苗和免疫计划的优势不应再仅以挽救的生命数量来衡量，而应考虑直接和间接的成本节约以及对个人和社会健康与福祉的整体益处。虽然水痘和甲型肝炎感染可能危及生命，但大多数病例是自限性的，且没有明显的后遗症。免疫接种更有可能提高生活质量而非挽救生命。在发展中国家，伤寒疫苗接种仍然是一项可能挽救生命的措施，但即使是更新的伤寒疫苗，其研发主要也是为了减少免疫接种不良反应的频率和严重程度，而非提高原始热酚灭活疫苗的保护效力。水痘病毒疫苗、甲型肝炎病毒疫苗和伤寒多糖Vi荚膜疫苗是免疫制剂的重要补充。这些疫苗具有免疫原性、临床有效且通常安全，不良反应罕见且通常轻微。它们良好的效益风险比应鼓励其合理使用。疾病控制与预防中心、美国儿科学会和美国家庭医师学会已经建议对儿童普遍接种水痘疫苗。未来几年可能会正式建议也对所有儿童常规使用甲型肝炎疫苗；与此同时，高危人群应接种疫苗。伤寒疫苗接种可能会继续选择性地用于那些与病原体有大量接触的人或前往伤寒流行国家的人。
