# Introducing the Concept of Small Vulnerable Newborns (SVN) as an Additional Endpoint to Evaluate Birth Outcomes in the Context of RSV Immunization Studies—A Commentary

## TL;DR

This commentary suggests using the concept of 'small vulnerable newborns' to better assess birth outcomes in RSV vaccination studies.

## Contribution

The paper introduces the 'small vulnerable newborns' concept as a new endpoint for evaluating maternal RSV vaccination outcomes.

## Key findings

- Differences in preterm birth rates between RSV vaccine studies appear inconsistent.
- The 'small vulnerable newborns' concept could provide a more nuanced evaluation of birth outcomes.
- This approach may improve understanding of maternal RSV vaccination effects.

## Abstract

Infection with respiratory syncytial virus (RSV) represents a substantial burden of disease, especially in children. While one vaccine (RSVpreF) has been recommended for administration in pregnant women, another one (RSVPreF3‐Mat) has been discontinued in a Phase 3 study due to an increased incidence of preterm births in the study group. When comparing the studies related to these two vaccine candidates, the differences in preterm birth rates appear inconsistent. For a more differentiated evaluation of birth outcomes associated with maternal RSV vaccination, we recommend introducing the previously described concept of “small and vulnerable newborns.”