Metselaar D, McDonald K, Gemert W, van Rens M M, Muller A S
Bull World Health Organ. 1977;55(6):755-9.
In tropical countries, seroconversion rates following oral poliomyelitis vaccination are frequently unsatisfactory. In an area of the Machakos district in Kenya, 4000 children under 5 years of age have been registered and are visited fortnightly by trained field staff as part of a comprehensive, population-based, longitudinal surveillance project. It was considered possible that poliomyelitis vaccine, given orally to children twice or three times at home, would produce satisfactory conversion rates. After collection of blood from a random sample of the children, vaccine was given twice to all children under 5 years of age. Blood was then collected a second time from a different sample of children. After a third dose of vaccine, a third blood collection followed. The percentages of the children that received vaccine each round were calculated and the sera tested for antibodies. It appeared that the mean titre was more strongly related to age than to the number of doses of poliomyelitis vaccine received. Improvement of herd immunity after two vaccine distributions was significant for a few age groups and for two types of vaccine only. In none of the groups was a significant improvement obtained by the third vaccine distribution. The problems associated with vaccination by live poliomyelitis vaccine in tropical countries are discussed in relation to the results.
在热带国家，口服脊髓灰质炎疫苗后的血清转化率常常不尽人意。在肯尼亚马查科斯区的一个地区，4000名5岁以下儿童已登记在册，作为一个全面的、基于人群的纵向监测项目的一部分，训练有素的现场工作人员每两周对他们进行一次访视。人们认为，在儿童家中给他们口服两次或三次脊髓灰质炎疫苗，可能会产生令人满意的转化率。从儿童中随机抽取样本采集血液后，给所有5岁以下儿童接种两次疫苗。然后从另一组不同的儿童样本中再次采集血液。在接种第三剂疫苗后，进行第三次血液采集。计算了每轮接种疫苗的儿童百分比，并对血清进行抗体检测。结果显示，平均滴度与年龄的相关性比与接种脊髓灰质炎疫苗的剂量数的相关性更强。两轮疫苗接种后，仅少数年龄组和两种疫苗类型的群体免疫有显著改善。第三次疫苗接种在任何组中均未取得显著改善。结合研究结果讨论了热带国家使用口服脊髓灰质炎活疫苗接种所存在的问题。
