Vázquez Marietta, LaRussa Philip S, Gershon Anne A, Niccolai Linda M, Muehlenbein Catherine E, Steinberg Sharon P, Shapiro Eugene D
Department of Pediatrics, Yale University School of Medicine, New Haven, Conn 06520-8064, USA.
JAMA. 2004 Feb 18;291(7):851-5. doi: 10.1001/jama.291.7.851.
Reports of outbreaks of varicella in highly immunized groups have increased concern about the effectiveness of varicella vaccine.
To assess whether the effectiveness of varicella vaccine is affected either by time since vaccination or by age at the time of vaccination.
Case-control study conducted from March 1997 through June 2003.
Twenty different group practices in southern Connecticut.
Case subjects, identified by active surveillance of all practices, consisted of 339 eligible children 13 months or older who were clinically diagnosed as having chickenpox and who also had a polymerase chain reaction (PCR) test result that was positive for varicella-zoster virus DNA. For each case subject, 2 controls were selected, matched by both age and pediatric practice.
The effectiveness of the vaccine, especially the effects of time since vaccination and age at the time of vaccination, adjusted for possible confounders.
Although the adjusted overall effectiveness of the vaccine was 87% (95% confidence interval, 81%-91%; P<.001), there was a substantial difference in the vaccine's effectiveness in the first year after vaccination (97%) and in years 2 to 8 after vaccination (84%, P =.003). The vaccine's effectiveness in year 1 was substantially lower if the vaccine was administered at younger than 15 months (73%) than if it was administered at 15 months or older (99%, P =.01), although the difference in effectiveness overall for children immunized at younger than 15 months was not statistically significantly different than for those immunized at 15 months or older (81% vs 88%, P =.17). Most cases of chickenpox in vaccinees were mild.
Although varicella vaccine is effective, its effectiveness decreases significantly after 1 year, although most cases of breakthrough disease are mild. If administered at younger than 15 months, the vaccine's effectiveness was lower in the first year after vaccination, but the difference in effectiveness was not statistically significant for subsequent years.
在高免疫群体中水痘暴发的报告增加了人们对水痘疫苗有效性的担忧。
评估水痘疫苗的有效性是否受接种疫苗后的时间或接种时年龄的影响。
1997年3月至2003年6月进行的病例对照研究。
康涅狄格州南部的20个不同的团体诊所。
通过对所有诊所进行主动监测确定的病例受试者包括339名13个月及以上符合条件的儿童，这些儿童临床诊断为患水痘，且其水痘带状疱疹病毒DNA聚合酶链反应（PCR）检测结果呈阳性。对于每个病例受试者，选择2名对照，根据年龄和儿科诊所进行匹配。
调整可能的混杂因素后疫苗的有效性，尤其是接种疫苗后的时间和接种时年龄的影响。
尽管调整后的疫苗总体有效性为87%（95%置信区间，81%-91%；P<.001），但疫苗在接种后第1年（97%）和接种后第2至8年（84%，P =.003）的有效性存在显著差异。如果在15个月龄以下接种疫苗，第1年疫苗的有效性（73%）显著低于在15个月龄及以上接种时（99%，P =.01），尽管15个月龄以下接种疫苗的儿童总体有效性差异与15个月龄及以上接种疫苗的儿童相比无统计学显著差异（81%对88%，P =.17）。疫苗接种者中的大多数水痘病例为轻症。
尽管水痘疫苗有效，但其有效性在1年后显著下降，尽管大多数突破性疾病病例为轻症。如果在15个月龄以下接种，疫苗在接种后第1年的有效性较低，但随后几年有效性差异无统计学意义。
Zotero 插件