Does influenza vaccination improve pregnancy outcome? Methodological issues and research needs

Area of Science:

• Perinatal health
• Vaccinology
• Epidemiology

Background:

• Increasing evidence supports the safety and efficacy of influenza vaccination during pregnancy.
• Reports suggest influenza vaccination may reduce adverse pregnancy outcomes, prompting further investigation.
• Maternal immunization programs' impact on mortality is modest, but could increase significantly if pregnancy outcome benefits are confirmed.

Purpose of the Study:

• To examine evidence and methodological issues regarding influenza vaccination and pregnancy outcomes, specifically preterm birth and fetal growth restriction.
• To identify research needs for a comprehensive understanding of influenza vaccination's role in improving pregnancy outcomes.

Main Methods:

• Review of existing evidence on influenza vaccination and pregnancy outcomes.
• Analysis of methodological limitations in current studies, including confounding and longitudinal data.
• Assessment of the quality of evidence linking influenza to adverse pregnancy outcomes.

Main Results:

• Strong empirical evidence confirms influenza vaccination prevents influenza in pregnant women.
• Evidence linking influenza infection to adverse pregnancy outcomes is inconsistent and of limited quality.
• Studies on vaccination and pregnancy outcomes show mixed results, with limitations in disease assessment and confounding control.

Conclusions:

• Further research, including randomized trials and re-analysis of observational studies, is recommended.
• Addressing confounding factors and longitudinal aspects of pregnancy is crucial for accurate assessment.
• Collaborative efforts among experts are needed to quantify the benefits of maternal influenza vaccination for pregnancy outcomes.