Research on vaccines during pregnancy: protocol design and assessment of safety.

The Division of Microbiology and Infectious Diseases at the National Institute of Allergy and Infectious Diseases, National Institutes of Health organized a series of conferences, entitled "Enrolling Pregnant Women in Clinical Trials of Vaccines and Therapeutics", to discuss study design and the assessment of safety in clinical trials conducted in pregnant women. A panel of experts was charged with developing guiding principles for the design of clinical trials and the assessment of safety of vaccines during pregnancy. Definitions and a grading system to evaluate local and systemic reactogenicity, adverse events, and other events associated with pregnancy and delivery were developed. The purpose of this report is to provide investigators interested in vaccine research in pregnancy with a basic set of tools to design and implement maternal immunization studies which may be conducted more efficiently using consistent definitions and grading of adverse events to allow the comparison of safety reports from different trials. These guidelines and safety assessment tools may be modified to meet the needs of each particular protocol based on evidence collected as investigators use them in clinical trials in different settings and share their findings and expertise.