Giorgi Rossi Paolo, Faustini Annunziata, Spadea Teresa, Perucci Carlo A
Department of Epidemiology, ASL Roma E, Rome, Italy.
Eur J Epidemiol. 2004;19(10):979-85. doi: 10.1007/s10654-004-5758-6.
The reliability of information sources, as well as the precision of coverage indicators are open questions for immunisation coverage surveys.
A sample survey of 323 children from two birth cohorts (1991-1992 and 1979-1981) was done. The sample was selected from seven health districts out of 51 in the Lazio region. The information was collected from vaccination cards or from parents, using a mail-in questionnaire. We computed three indicators of coverage at 24 months of age for polio, diphtheria-tetanus, pertussis (P), hepatitis B, and measles (M), depending on the value given to parental recall. We also compared up-to-date (UTD) (immunised children at 24 months) and age-appropriate (months at risk per child) indicators at the local level.
Response rate was 68.2%. The two birth cohorts were similarly immunised for polio (coverage 95%); the younger cohort had higher coverage levels for diphtheria-tetanus (93% vs. 75%), for P (30% vs. 22%), for M (43% vs. 16%) than the older one, even on the basis of parental recall. In the older cohort, diphtheria-tetanus, P and M coverage levels were 75, 22 and 15%, respectively, on the basis of parental recall and 66, 17 and 4% on certification. The age-appropriate indicator revealed four districts that completed vaccinations significantly too late, while the UTD indicator showed only one district significantly below the threshold of 95% of immunized children at 24 months.
Parental recall and data from cards are comparable sources, but the former is more sensitive than the latter in retrospective studies. Verbal recall should be accepted as reasonably reliable in the absence of cards. Age-appropriate indicators give a more complete evaluation of the susceptibility in the population, and are more precise at the local level.
免疫接种覆盖率调查中，信息来源的可靠性以及覆盖指标的精确性都是有待解决的问题。
对来自两个出生队列（1991 - 1992年和1979 - 1981年）的323名儿童进行了抽样调查。样本选自拉齐奥地区51个卫生区中的7个。通过邮寄问卷从疫苗接种卡或家长处收集信息。根据家长回忆提供的值，我们计算了24月龄时脊髓灰质炎、白喉 - 破伤风、百日咳（P）、乙型肝炎和麻疹（M）的三项覆盖率指标。我们还在地方层面比较了最新（UTD）（24月龄时已免疫儿童）和适龄（每个儿童的风险月龄）指标。
回复率为68.2%。两个出生队列在脊髓灰质炎免疫接种方面情况相似（覆盖率95%）；较年轻的队列在白喉 - 破伤风（93%对75%）、P（30%对22%）、M（43%对16%）方面的覆盖率高于较年长的队列，即使是基于家长回忆。在较年长的队列中，基于家长回忆，白喉 - 破伤风、P和M的覆盖率分别为75%、22%和15%，基于证明则分别为66%、17%和4%。适龄指标显示有四个区完成疫苗接种明显过晚，而UTD指标仅显示一个区显著低于24月龄时95%免疫儿童的阈值。
家长回忆和卡片数据是可比的信息来源，但在回顾性研究中，前者比后者更敏感。在没有卡片的情况下，口头回忆应被视为具有合理的可靠性。适龄指标能更全面地评估人群中的易感性，且在地方层面更精确。
