title: Surveillance of Adverse Events After Seasonal Influenza Vaccination in Pregnant Women and Their Infants in the Vaccine Adverse Event Reporting System, July 2010-May 2016.
abstract: Routine immunization of pregnant women with seasonal inactivated influenza vaccines (IIVs) is recommended in all trimesters of pregnancy. A review of the Vaccine Adverse Event Reporting System (VAERS) during 1990-2009 did not find any unexpected patterns of pregnancy complications or fetal outcomes after administration of IIV or live attenuated influenza vaccines (LAIVs). During the 2009-2010 pandemic influenza A (H1N1) vaccination campaign, a study noted that the number of VAERS reports from pregnant women who received the H1N1 2009 inactivated monovalent vaccine (n = 288) increased compared with 1990-2009 seasonal IIV pregnancy reports (n = 148).
  
  
  
  The objective of this study was to assess the safety of seasonal influenza vaccines in pregnant women and their infants whose reports were submitted to VAERS during 2010-2016.
  
  
  
  We searched VAERS for US reports of adverse events (AEs) in pregnant women who received IIV or LAIV from 1 July 2010 through 6 May 2016. Clinicians reviewed reports and available medical records and assigned a primary clinical category for each report. Reports were coded as serious based on the Code of Federal Regulations.
  
  
  
  We identified 671 reports after seasonal influenza vaccines administered to pregnant women: 544 after IIV and 127 after LAIV. Serious events occurred among 61 (11.2%) reports following IIV and one (0.8%) report following LAIV. No deaths were reported. Among reports with trimester information (n = 296), IIV was administered during the first trimester in 116 (39.2%). Among IIV reports, the most frequent pregnancy-specific AE was spontaneous abortion in 62 (11.4%) reports, followed by stillbirth in ten (1.8%) and preterm delivery in six (1.1%). The most common non-pregnancy-specific AEs were injection-site reactions (55 [10.1%]). Neonatal or infant outcomes were reported in 22 (4.0%) reports, seven of which had major birth defects of different types and no neonatal deaths.
  
  
  
  As in 2009-2010, no new or unexpected patterns in maternal or fetal outcomes were observed during 2010-2016.
authors.affiliation: Immunization Safety Office, Division of Healthcare Quality Promotion, National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Centers for Disease Control and Prevention (CDC), 1600 Clifton Rd, MS D26, Atlanta, GA, 30329, USA. pmoro@cdc.gov.
authors.forename: Pedro
authors.initials: P
authors.lastname: Moro
authors.affiliation: Division of Epidemiology, Office of Biostatistics and Epidemiology, Center for Biologics Evaluation and Research, US Food and Drug Administration (FDA), Silver Spring, MD, USA.
authors.forename: Jane
authors.initials: J
authors.lastname: Baumblatt
authors.affiliation: Immunization Safety Office, Division of Healthcare Quality Promotion, National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Centers for Disease Control and Prevention (CDC), 1600 Clifton Rd, MS D26, Atlanta, GA, 30329, USA.
authors.forename: Paige
authors.initials: P
authors.lastname: Lewis
authors.affiliation: Birth Defects Branch, Division of Congenital and Developmental Disabilities, National Center on Birth Defects and Developmental Disabilities (NCBDDD), CDC, Atlanta, GA, USA.
authors.forename: Janet
authors.initials: J
authors.lastname: Cragan
authors.affiliation: Women's Health and Fertility Branch, Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP), CDC, Atlanta, GA, USA.
authors.forename: Naomi
authors.initials: N
authors.lastname: Tepper
authors.affiliation: Immunization Safety Office, Division of Healthcare Quality Promotion, National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Centers for Disease Control and Prevention (CDC), 1600 Clifton Rd, MS D26, Atlanta, GA, 30329, USA.
authors.forename: Maria
authors.initials: M
authors.lastname: Cano
mesh_terms: D000293:Adolescent; D000328:Adult; D016907:Adverse Drug Reaction Reporting Systems; D002648:Child; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000009:adverse effects*; D007251:Influenza, Human / Q000517:prevention & control*; D008875:Middle Aged; D011247:Pregnancy; D011256:Pregnancy Outcome; D012621:Seasons; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000009:adverse effects; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000009:adverse effects; D055815:Young Adult
chemical_list: D007252:Influenza Vaccines; D014613:Vaccines, Attenuated; D015164:Vaccines, Inactivated