The indirect cohort method is a case-control type design which uses cases caused by non-vaccine serotypes as controls. 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 (Vaccine 2012;30(27):4067-72) applied this method to evaluate the effectiveness of a pneumococcal conjugate vaccine 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. The authors considered the 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. Using the Indirect Cohort Design to Estimate the Effectiveness of the Seven Valent Pneumococcal Conjugate Vaccine in England and Wales (PLoS ONE 6(12):e28435. doi:10.1371/journal.pone.0028435) describes how the method was used to estimate effectiveness of various numbers of doses as well as for each vaccine serotype.
|Annex 1.||Guidance on conducting systematic revies and meta-analyses of completed comparative pharmacoepidemiological studies of safety outcomes|