Methodologic approaches in studies using real-world data (RWD) to measure pediatric safety and effectiveness of vaccines administered to pregnant women: A scoping review.

Objective: This scoping review mapped studies using real-world data (RWD) to measure pediatric safety and effectiveness of vaccines administered to pregnant women.

Introduction: In the US, two vaccines are recommended for all pregnant women to prevent illness in the infant: inactivated influenza vaccine (recommended since 2004), and the combined tetanus-diphtheria-acellular pertussis (Tdap) vaccine (recommended since 2013). This scoping review maps the studies conducted to date that address questions about pediatric safety and effectiveness of vaccines administered during pregnancy and provides a knowledge base for evaluating the use of RWD to study this issue.

Methods: The scoping review was conducted following a published protocol. Methods included an electronic search of PubMed and Embase, screening of titles and abstracts by two reviewers, and double extraction of data for summary and synthesis. Studies that reported on pregnant women and the effectiveness or safety outcomes in their infants were included.

Results: Forty-eight studies met the inclusion criteria of the scoping review protocol using RWD to assess safety or effectiveness of influenza or pertussis vaccinations administered to pregnant women with respect to pregnancy, infant or child outcomes. Detailed information about data sources, linkage of maternal and infant data, and operational definitions for gestational age were largely absent from the majority of studies raising concerns about reproducibility and validity of study findings.

Conclusions: A body of literature is available from which to plan and design future studies of vaccination in pregnant women using RWD. This is of intense importance as new vaccines, such as those for COVID-19, become available to the general population via approval or authorization without inclusion of pregnant women in the clinical trials.