Peltola H, Virtanen M, Mäkelä P H
Pathol Biol (Paris). 1983 Feb;31(2):141-3.
48,997 children of 3 months to 5 years were vaccinated with Haemophilus influenzae type b (Hib) capsular polysaccharide vaccine in a double blind study carried out in Finland in 1974. A clear-cut effect was obtained in the incidence of epiglottitis. The number of patients decreased 58% for three years when compared with the three-year-period before vaccination (p less than 0.002). On the other hand, the number of cases during the three years following vaccination was 65% less than during the next three year period (p less than 0.001). The efficacy implies an exceptionally strong herd immunity, because only 37.7% of the children in the area were vaccinated. Regarding meningitis, no herd immunity was observed but vaccination induced a highly significant (p less than 0.001) individual protection (2 cases in the specifically vaccinated versus 20 in the control group in four years' time), provided the vaccine was given at the age of 18 months or later. No efficacy was obtained before this age limit. It was calculated that approximately 90 per cent of cases of epiglottitis and 50 per cent of meningitis would be prevented with the vaccine currently available. Taking also into account the strong herd immunity tendency, vaccination is likely to offer even larger benefits.
1974年在芬兰开展的一项双盲研究中，48997名3个月至5岁的儿童接种了b型流感嗜血杆菌（Hib）荚膜多糖疫苗。在会厌炎发病率方面取得了明显效果。与接种疫苗前的三年期相比，三年间患者数量减少了58%（p<0.002）。另一方面，接种疫苗后的三年间病例数比接下来三年期少65%（p<0.001）。这种有效性意味着存在异常强大的群体免疫力，因为该地区只有37.7%的儿童接种了疫苗。关于脑膜炎，未观察到群体免疫力，但接种疫苗产生了高度显著（p<0.001）的个体保护作用（四年时间里，特定接种组有2例，而对照组有20例），前提是在18个月及以后接种疫苗。在这个年龄限制之前未获得有效性。据计算，使用目前可用的疫苗可预防约90%的会厌炎病例和50%的脑膜炎病例。再考虑到强大的群体免疫趋势，接种疫苗可能会带来更大的益处。
