Safety of influenza AH1N1 pandemic vaccination during pregnancy: a comparative study using the EFEMERIS database

Study type

• Study topic:
  Disease /health condition

  Human medicinal product
• Study type:
  Non-interventional study
• Scope of the study:
  Assessment of risk minimisation measure implementation or effectiveness

  Drug utilisation
• Data collection methods:
  Secondary use of data

Non-interventional study

• Non-interventional study design:
  Cohort

Study drug and medical condition

• Name of medicine, other:
  INFLUENZA A (H1N1) 2009 MONOVALENT VACCINE

Population studied

• Short description of the study population:
  Pregnant women in EFEMERIS database who were either exposed or unexposed to influenza AH1N1 vaccine and who delivered from October 21th 2009 to November 30th 2010 in Haute-Garonne.
• Age groups:
  • Paediatric Population (< 18 years)

    • Neonate

      • Preterm newborn infants (0 – 27 days)
      • Term newborn infants (0 – 27 days)
    • Infants and toddlers (28 days – 23 months)
• Special population of interest:
  Pregnant women
• Estimated number of subjects:
  5000

Study design details

• Main study objective:
  The main objective was to evaluate the risk of adverse pregnancy outcomes following A/H1N1 vaccination in pregnant women.
• Outcomes:
  all-cause pregnancy loss, preterm delivery, small for gestational age (SGA) and neonatal pathology
• Data analysis plan:
  The study compared vaccinated and non-vaccinated pregnant women. Two non-vaccinated women were individually matched to each vaccinated women by month and year of pregnancy onset. Multivariable conditional logistic regression and multivariable cox proportional hazards regression were used to evaluate associations between each outcome (all-cause pregnancy loss, preterm delivery, small for gestational age (SGA) and neonatal pathology) and A/H1N1 vaccination during pregnancy.