Risk of Adverse Fetal Outcomes Following Administration of a Pandemic Influenza A(H1N1) Vaccine During Pregnancy

Abstract

HE 2009 INFLUENZA A(H1N1) p a n d e m i c p u t p r e g n a n t women at increased risk of morbidity, mortality, and poor pregnancy outcomes. [1][2][3][4] Pregnant women were among the main target groups prioritized for vaccination against influenza A(H1N1)pdm09, 5 and an estimated 2.4 million women were vaccinated during pregnancy in the United States alone. 6 However, assessment of the fetal safety of H1N1 vaccination in pregnancy has been limited to a few pharmacovigilance reports and descriptive cohort studies. [6][7][8][9][10][11][12][13][14] In a registry-based cohort study, we investigated whether exposure to an AS03-adjuvanted influenza A(H1N1) pdm09 vaccine in pregnancy was associated with increased risk of major birth defects, preterm birth, and fetal growth restriction. METHODSWe conducted a nationwide registrybased cohort study of liveborn infants in Denmark. Individual-level data on H1N1 vaccination during pregnancy and potential confounders in cohort moth-

Prematurity and the burden of influenza and respiratory syncytial virus disease

“…[72] Receipt of different influenza vaccine during pregnancy was not associated with increased or decreased risk of preterm or SGA birth or congenital malformations. [73][74][75] These recent findings support the safety of vaccinating pregnant women against infl uenza during the fi rst, second, and third trimesters.…”

2009 A/H1N1 influenza vaccination in pregnancy: uptake and pregnancy outcomes – a historical cohort study

“…Influenza vaccination is not associated with adverse pregnancy outcomes including fetal death, preterm birth and congenital anomalies. (12)(13)(14)(15)(16)(17) Vaccination may have reduced the risk of influenza-related fetal death during the pandemic. (12) It is essential that extensive data are available on pregnancy outcomes after gestational vaccine exposure in order to inform decisions on vaccination by pregnant women and health professionals, particularly during a pandemic situation.…”

Vaccines and immunoglobulins

“…Over 110,000 vaccinated pregnancies have been documented in numerous publications from Europe, United States, Asia and South America. In these publications almost 41,000 women were vaccinated with non-adjuvanted vaccine (Chavant 2013, Fell 2012, Oppermann 2012, Huang 2011, over 60,000 women with AS03-adjuvanted 2009 H1N1 vaccine (Håberg 2013, Källén 2012, Oppermann 2012, Pasternak 2012, Sammon 2012, and more than 10,000 pregnancies with MF-59-adjuvanted 2009 H1N1 vaccine (Rubinstein 2013, Heikkinen 2012, Huang 2011. Only a small number of the women were vaccinated during the first trimester.…”

“…This could potentially result in placental dysfunction and a higher risk of preeclampsia, as a disturbed Th1/Th2 regulation has been discussed for some time as a cause of placental dysfunction (Mor 2010, Trowsdale 2006, Saito 2003. However, studies did not find any adverse effect of the AS03-or MF59-adjuvanted A/H1N1 vaccines on the ongoing pregnancy, or on the health of the mother, the fetus, or the newborn (Håberg 2013, Rubinstein 2013, Heikkinen 2012, Källén 2012, Oppermann 2012, Pasternak 2012, Sammon 2012, Huang 2011.…”