Use of surveillance data to estimate the effectiveness of the 7-valent conjugate pneumococcal vaccine in children less than 5 years of age over a 9 year period

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• 作者：Gaston De Serres^a ; Tamara Pilishvili^b ; ^{tpilishvili@cdc.gov} ; ^tdp4@cdc.gov ; Ruth Link-Gelles^b ; Arthur Reingold^c ; Kenneth Gershman^d ; Susan Petit^e ; Monica M. Farley^f ; Lee H. Harrison^g ; Ruth Lynfield^h ; Nancy M. Bennettⁱ ; Joan Baumbach^j ; Ann Thomas^k ; William Schaffner^l ; Bernard Beall^b ; Cynthia Whitney^b ; Matthew Moore^b
• 关键词：Pneumococcal conjugate vaccine ; Indirect cohort method ; Vaccine effectiveness
• 出版年：2012
• 出版时间：8 June, 2012
• 年：2012
• 卷：30
• 期：27
• 页码：4067-4072
• 全文大小：243 K

文摘

Background

Case-control studies evaluating post-licensure effectiveness of conjugate vaccines can be laborious and costly. We applied an indirect cohort method to evaluate the effectiveness of seven-valent pneumococcal conjugate vaccine (PCV7) against invasive pneumococcal disease (IPD) and compared the results to the effectiveness measured using a standard case-control study conducted during the same time period.

Methods

IPD cases among children 2-59 months old were identified through the Active Bacterial Core surveillance system during 2001-2009. We used logistic regression to calculate the odds ratio of vaccination (versus no vaccination) among cases (PCV7-type IPD cases) and non-cases (non-PCV7-type IPD cases), controlling for the presence of underlying conditions. Vaccine effectiveness (VE) was calculated as one minus the adjusted odds ratio.

Results

Among 4225 IPD cases reported during 2001-2009, 2680 (63 % ) had serotype information and vaccine history. Effectiveness of ? dose of PCV7 against PCV7-types was 88 % (95 % confidence interval (CI) 78-94 % ) among children with comorbid conditions and 97 % (95 % CI 92-98 % ) among healthy children. Among healthy children, VE was higher in 2001-2003 (97 % , 95 % CI 95-98 % ) compared to 2004-2009 (81 % , 95 % CI 64-90 % ). The annual estimates of VE in 2004-2009 showed great variability and wide confidence intervals due to the small number of PCV7-type cases.

Conclusions

An indirect cohort design using IPD surveillance data confirms the findings of the case-control study and, therefore, appears suitable for estimating PCV7effectiveness. This method would be most useful shortly after vaccine introduction, and less useful in a setting of very high vaccine coverage and fewer vaccine-type cases.