Clark Andrew, Sanderson Colin
Department of Public Health and Policy, London School of Hygiene and Tropical Medicine, London, UK.
Lancet. 2009 May 2;373(9674):1543-9. doi: 10.1016/S0140-6736(09)60317-2. Epub 2009 Mar 19.
Vaccinations are often delayed until well after the recommended ages, leaving many children exposed for longer than they should be. We estimated vaccination coverage at different ages, and delays in administration, in 45 low-income and middle-income countries.
We used data for 217 706 children from Demographic and Health Surveys between 1996 and 2005 (median 2002), which provided data for vaccination of children on the basis of events recorded on vaccination cards and interviews with mothers, with imputation of missing values and survival analysis. We devised an index combining coverage and delay.
For vaccinated children, the median of the median delays in the 45 countries was 2.3 weeks (IQR 1.4-4.6) for bacille Calmette-Guérin (BCG); 2.4 weeks (1.2-3.3) for diphtheria, tetanus, and pertussis (DTP1); 2.7 weeks (1.7-3.1) for measles-containing vaccine (MCV1); and 6.2 weeks (3.5-8.5) for DTP3. However, in the 12 countries with the longest delays for each vaccination, at least 25% of the children vaccinated were more than 10 weeks late for BCG, 8 weeks for DTP1, 11 weeks for MCV1, and 19 weeks for DTP3. Variation within countries was substantial: the median of the IQRs in the 45 countries for delay in DTP3 was 10.9 weeks, 7.9 weeks for MCV1, 5.4 weeks for BCG, and 5.3 weeks for DTP1. The median of the national coverage rates for DTP1 increased from 57% in children aged 12 weeks to 88% at 12 months, and for DTP3 from 65% at 12 months to 76% at 3 years.
The timeliness of children's vaccination varies widely between and particularly within countries, and published yearly estimates of national coverage do not capture these variations. Delayed vaccination could have important implications for the effect of new and established vaccines on the burden of disease.
WHO's Initiative for Vaccine Research.
疫苗接种常常推迟到远远超过推荐年龄之后，致使许多儿童暴露于疾病风险中的时间比应有的更长。我们估算了45个低收入和中等收入国家不同年龄儿童的疫苗接种覆盖率以及接种延迟情况。
我们使用了1996年至2005年（中位数为2002年）人口与健康调查中217706名儿童的数据，这些数据是基于疫苗接种卡上记录的事件以及与母亲的访谈来提供儿童疫苗接种情况的，同时进行了缺失值插补和生存分析。我们设计了一个综合覆盖率和延迟情况的指数。
对于已接种疫苗的儿童，45个国家中卡介苗（BCG）接种延迟中位数的中位数为2.3周（四分位间距1.4 - 4.6）；白喉、破伤风和百日咳疫苗（DTP1）为2.4周（1.2 - 3.3）；含麻疹疫苗（MCV1）为2.7周（1.7 - 3.1）；DTP3为6.2周（3.5 - 8.5）。然而，在每种疫苗接种延迟最长的12个国家中，至少25%的已接种儿童接种BCG延迟超过10周，接种DTP1延迟超过8周，接种MCV1延迟超过11周，接种DTP3延迟超过19周。国家内部的差异很大：45个国家中DTP3接种延迟的四分位间距中位数为10.9周，MCV1为7.9周，BCG为5.4周，DTP1为5.3周。DTP1的国家覆盖率中位数在12周龄儿童中为57%，在12月龄时增至88%；DTP3在12月龄时为6%，在3岁时为76%。
儿童疫苗接种的及时性在不同国家之间差异很大，尤其是在国家内部，并且每年公布的国家覆盖率估算未能反映这些差异。接种延迟可能对新老疫苗在疾病负担方面的效果产生重要影响。
世界卫生组织疫苗研究倡议组织。
