Impact of Maternal Influenza Vaccination During Pregnancy on the Incidence of Acute Respiratory Illness Visits Among Infants | Geriatrics | JAMA Pediatrics | JAMA Network
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December 2006

Impact of Maternal Influenza Vaccination During Pregnancy on the Incidence of Acute Respiratory Illness Visits Among Infants

Author Affiliations

Author Affiliations: Department of Preventive Medicine (Dr France) and Clinical Research Unit (Ms Smith-Ray and Drs McClure, Hambidge, Xu, and Yamasaki), Kaiser Permanente Colorado, Denver; The National Immunization Program, Influenza Branch (Dr Shay), Vaccine Safety Branch (Mr Weintraub), and Respiratory and Enteric Viruses Branch (Dr Fry), Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Ga; Kaiser Permanente Vaccine Study Center, Oakland, Calif (Drs Black and Shinefield); Center for Health Research, Kaiser Permanente Northwest, Portland, Ore (Dr Mullooly); and The Center for Health Studies, Group Health Cooperative, Seattle, Wash (Dr Jackson). The Vaccine Safety Branch has been transferred to the Office of the Chief Science Officer, Office of the Director, Centers for Disease Control and Prevention. Ms Smith-Ray is now with Human Cognitive Neuroscience at the University of Edinburgh, Edinburgh, Scotland.

Arch Pediatr Adolesc Med. 2006;160(12):1277-1283. doi:10.1001/archpedi.160.12.1277

Objective  To determine whether influenza vaccination of pregnant women prevents visits for respiratory illness in their infants born during the influenza season.

Design  Retrospective matched cohort study.

Setting  Four managed care organizations in the United States.

Patients  A total of 41 129 infants (3160 and 37 969 born to vaccinated and unvaccinated mothers, respectively) born between 1995 and 2001.

Main Exposure  Maternal influenza vaccination. Infants were considered exposed if their gestational age at birth was at least 30 weeks, if the time from maternal vaccination to birth was at least 28 days, and if they were exposed to at least 14 days of the influenza season.

Main Outcome Measures  Incidence of acute respiratory illnesses (outpatient, emergency department, and inpatient settings combined) and incident rate ratios (IRRs) for infants exposed and unexposed to maternal vaccination during the following 4 periods: peak influenza, respiratory syncytial virus predominant, periseasonal, and summer weeks. The time to the first acute respiratory illness during peak influenza weeks was also assessed.

Results  During the peak influenza weeks, infant visit rates were 15.4 and 17.1 per 100 person-months for exposed and unexposed infants, respectively (IRR, 0.90; 95% confidence interval, 0.80-1.02). Adjusted IRRs for the 4 periods found a protective effect of infant female sex, whereas Medicaid status and maternal high-risk status increased infant visit rates. Maternal influenza vaccination did not reduce visit rates during any of the 4 time periods (IRR for peak influenza season, 0.96; 95% confidence interval, 0.86-1.07) and did not delay the onset of first respiratory illness.

Conclusion  We were unable to demonstrate that maternal influenza vaccination reduces respiratory illness visit rates among their infants.