Article type
Abstract
Background: An increasing number of vaccine safety studies using the self-controlled case-series (SCCS) design have been conducted in the last decade. However, there has been no comprehensive evaluation of the methodology and reporting quality of these observational studies. The purpose of this paper is to document the methodological features of studies that focused on vaccine safety using the SCCS design, and to evaluate the reporting quality of these studies to suggest future improvements on appropriate design and transparent reporting.
Methods: Databases including Medline, Embase, Web of Science, Scopus and Chinese databases were searched from inception to May 31, 2021. All observational studies regarding vaccine safety using a SCCS design were selected. Information regarding methodological elements were extracted. In addition, reporting quality was assessed using the REporting of studies Conducted using Observational Routinely collected health Data statement for PharmacoEpidemiology (RECORD-PE).
Results: Of the 105 studies identified, administrative databases were the main data source for vaccination records and adverse events following immunization (AEFI). 28 articles (27%) used multiple designs to verify the association, and the results obtained with the SCCS design were robust. The top three AEFI studied were intussusception, Guillain-Barré syndrome, and convulsion. Only 21 studies (20%) reported the approach for case validation by chart review. The healthy vaccinee effect was considered by 51 studies (49%), with 17 of them (33%) using extended SCCS models to alleviate this effect. Overall, the reporting quality of included studies could be improved.
Conclusions: This study systematically reviewed the methodology of studies regarding vaccine safety using a SCCS design and critically assessed their respective reporting quality. Case validation, the validity of assumptions for standard SCCS, and quality of reporting should be given more importance in future research projects.
Methods: Databases including Medline, Embase, Web of Science, Scopus and Chinese databases were searched from inception to May 31, 2021. All observational studies regarding vaccine safety using a SCCS design were selected. Information regarding methodological elements were extracted. In addition, reporting quality was assessed using the REporting of studies Conducted using Observational Routinely collected health Data statement for PharmacoEpidemiology (RECORD-PE).
Results: Of the 105 studies identified, administrative databases were the main data source for vaccination records and adverse events following immunization (AEFI). 28 articles (27%) used multiple designs to verify the association, and the results obtained with the SCCS design were robust. The top three AEFI studied were intussusception, Guillain-Barré syndrome, and convulsion. Only 21 studies (20%) reported the approach for case validation by chart review. The healthy vaccinee effect was considered by 51 studies (49%), with 17 of them (33%) using extended SCCS models to alleviate this effect. Overall, the reporting quality of included studies could be improved.
Conclusions: This study systematically reviewed the methodology of studies regarding vaccine safety using a SCCS design and critically assessed their respective reporting quality. Case validation, the validity of assumptions for standard SCCS, and quality of reporting should be given more importance in future research projects.