Pandemic A/H1N1 influenza vaccination during pregnancy: a comparative study using the EFEMERIS database.
OBJECTIVE
To evaluate the risk of adverse pregnancy outcomes following A/H1N1 vaccination in pregnant women.


METHODS
This observational cohort study compared vaccinated and non-vaccinated pregnant women in EFEMERIS, a French prescription database including pregnant women. Women who ended their pregnancy in South Western France between October 21, 2009 and November 30, 2010 (the period of the French vaccination campaign) were included. Two non-vaccinated women were individually matched to each vaccinated woman by month and year of pregnancy onset. Conditional logistic regression and 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.


RESULTS
1645 women of the 12,120 (13.6%) in the database who were administered A/H1N1 vaccine during pregnancy were compared to 3290 non-vaccinated women. Most were vaccinated in December 2009 (61%) with a non-adjuvanted vaccine (93%). The risks of pregnancy loss (adjusted HR=0.56; 95% CI=0.31-1.01), of preterm birth (adjusted HR=0.82; 95% CI=0.64-1.06), and of neonatal pathology (adjusted OR=0.70; 95% CI=0.49-1.02) did not differ between the vaccinated and the non-vaccinated groups. The rate of SGA was lower in the vaccinated group than in the non-vaccinated group (0.5% vs. 1.4%; adjusted OR=0.36; 95% CI=0.17-0.78).


CONCLUSIONS
There was no significant association between adverse pregnancy outcomes and vaccination with a non-adjuvanted A/H1N1 vaccine during pregnancy.
Service de Pharmacologie Médicale, CHU Toulouse, Université de Toulouse, Inserm 1027, Toulouse, France. Electronic address: beau.a@chu-toulouse.fr.
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Beau
Service de Pharmacologie Médicale, CHU Toulouse, Université de Toulouse, Inserm 1027, Toulouse, France.
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Hurault-Delarue
Caisse Primaire d'Assurance Maladie de la Haute-Garonne, CPAM, Toulouse, France.
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Vidal
Service de Protection Maternelle et Infantile, Conseil Général de la Haute-Garonne, Toulouse, France.
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Guitard
Centre de Diagnostic Anténatal, CDA, CHU Toulouse, Toulouse, France.
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Vayssière
Programme de Médicalisation des Systèmes d'Information; PMSI, CHU Toulouse, Toulouse, France.
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Petiot
Service de Pharmacologie Médicale, CHU Toulouse, Université de Toulouse, Inserm 1027, Toulouse, France.
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Montastruc
Service de Pharmacologie Médicale, CHU Toulouse, Université de Toulouse, Inserm 1027, Toulouse, France.
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Damase-Michel
Service de Pharmacologie Médicale, CHU Toulouse, Université de Toulouse, Inserm 1027, Toulouse, France.
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Lacroix
D000328:Adult; D005260:Female; D005602:France; D006801:Humans; D007236:Infant, Small for Gestational Age; D053118:Influenza A Virus, H1N1 Subtype; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000009:adverse effects; D007251:Influenza, Human / Q000517:prevention & control*; D016015:Logistic Models; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000517:prevention & control*; D011256:Pregnancy Outcome; D047928:Premature Birth; D016016:Proportional Hazards Models; D012307:Risk Factors; D014611:Vaccination / Q000009:adverse effects
D007252:Influenza Vaccines
Adverse fetal outcomes; EFEMERIS; Influenza A(H1N1); Pregnancy; Vaccination