Preterm birth is an important pregnancy outcome that may represent an adverse event. It is important to establish a case definition for use across vaccine studies and post-licensure surveillance. A functional case definition is important for the evaluation and assessment of data to help determine whether a vaccine administered during pregnancy may or may not be implicated in a subsequent preterm birth. The definition is to be applicable in regions that are geographically and administratively diverse, with varying available health care personnel, training and resources.
The Ritchie Centre
Infection and Immunity
Journal and article title
There is not a unanimously accepted definition of prematurity. The literature was notable for inconsistent definitions and numerous descriptions for preterm birth. Existing definitions categorise preterm birth by clinical presentation, birth weight and gestational age.
There is hence no uniformly accepted definition of preterm birth that is able to be employed to evaluate its occurrence following antenatal immunisations. This poses a missed opportunity and
a potential risk to immunisation trials and programmes as well as pregnant women, as potential associations may be falsely raised or dismissed without an agreed case definition.
An ideal standardised case definition aims to improve reliability and comparability of data collected from immunised mothers that deliver full term or preterm infants across all health care settings.