Journal Article

Safety of inactivated monovalent pandemic (H1N1) 2009 vaccination during pregnancy: A population-based study in Taiwan

Huang, Wan-Ting, Yang, Shu-Er, Chih, Yi-Chien, Chuang, Jen-Hsiang, Tang, Fa-Wei

2014

Overview

Pregnant women were prioritized for H1N1 vaccination during the 2009–2010 pandemic. Safety concerns exist with vaccinating pregnant women, particularly in their first trimesters. We linked computerized data on H1N1 vaccination, National Health Insurance, and Taiwan Birth Registry and identified events of spontaneous abortions (SABs) and all singleton births that occurred/delivered during November 1, 2009–September 30, 2010. The observation period for each case of SAB (6–19 weeks gestation) was divided into period at risk (1–28 days after vaccination) and control periods (the remaining person-days until SAB). The self-controlled case series method for truncated observational periods assessed the incidence rate ratio (IRR) of SAB during the 1–28 days compared with those in the control period. The case-control design matched each case of adverse fetal outcomes to up to 10 controls on fetal sex and year/month of pregnancy onset, and calculated matched odds ratio (OR) on H1N1 vaccination at <14 or ≥14 weeks gestation. Sixty-five women with SAB had received H1N1 vaccination at 6–19 weeks gestation. The IRR of SAB for the risk period 1–28 days was 1.03 (95% confidence interval [CI] 0.55–1.93). Among the 147,294 live births and 1354 stillbirths, maternal H1N1 vaccine receipt at <14 weeks gestation was associated with significantly reduced likelihood of small for gestational age (SGA) birth (OR 0.72, 95% CI 0.61–0.84) and birth defect (OR 0.46, 95% CI 0.22–1.00), whereas receipt at ≥14 weeks gestation was associated with significantly reduced likelihood of stillbirth (OR 0.63, 95% CI 0.46–0.86), prematurity (OR 0.90, 95% CI 0.83–0.97), low birth weight (OR 0.81, 95% CI 0.74–0.88), and SGA birth (OR 0.90, 95% CI 0.84–0.97). H1N1 vaccination during pregnancy did not increase risk of SAB or adverse fetal outcomes.

• Publisher: Elsevier Ltd,Elsevier,Elsevier Limited
• Subject: Abortion, Spontaneous - epidemiology / Adjuvants, Immunologic - administration & dosage / Adult / Allergy and Immunology / Applied microbiology / Biological and medical sciences / Birth defects / Birth weight / Births / Case-Control Studies / confidence interval / congenital abnormalities / Female / fetal death / Fundamental and applied biological sciences. Psychology / H1N1 virus / Humans / Immunization / Influenza A Virus, H1N1 Subtype / Influenza Vaccines - adverse effects / Influenza Vaccines - therapeutic use / Influenza, Human - prevention & control / low birth weight / Male / MF59 adjuvant / Microbiology / Miscellaneous / Odds Ratio / pandemic / Pandemics / Population studies / Pregnancy / Pregnancy Complications, Infectious - prevention & control / Pregnancy Outcome / pregnant women / premature birth / Premature Birth - epidemiology / risk / small for gestational age / Taiwan / Taiwan - epidemiology / vaccination / Vaccine safety / Vaccines / Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies (general aspects) / Virology / Womens health / Young Adult