December 3, 2010 / 59(47);1541-1545

Because pregnant women are at increased risk for severe disease associated with influenza infection, the American College of Obstetricians and Gynecologists and the Advisory Committee on Immunization Practices have recommended seasonal influenza vaccination for women while pregnant, regardless of trimester (1,2). In 2009, a novel strain of influenza A (H1N1) virus was identified (3), and pregnant women also were found to be at greater risk for influenza-related complications from this new virus (4). As a result, during the 2009--10 influenza season, two separate influenza vaccines were recommended to pregnant women: inactivated trivalent 2009--10 seasonal vaccine and influenza A (H1N1) 2009 monovalent vaccine (2,5). To estimate influenza vaccination coverage among pregnant women during the 2009--10 influenza season, CDC analyzed data from 10 states from the Pregnancy Risk Assessment Monitoring System (PRAMS). This report summarizes the results of that analysis, which determined that vaccination coverage for pregnant women among the 10 states combined was 50.7% for seasonal influenza and 46.6% for 2009 H1N1. In addition, women to whom vaccination was offered or recommended by their health-care provider were significantly more likely to report being vaccinated against seasonal influenza (relative risk [RR] = 3.3) and 2009 H1N1 (RR = 10.1). These results indicate substantially higher influenza vaccination coverage among pregnant women than has been reported for previous influenza seasons (2,5,6) and support previous findings that receipt of influenza vaccination can be influenced greatly by health-care providers offering or recommending influenza vaccination (6,7).

CDC analyzed data from PRAMS, an ongoing, population-based surveillance system that collects information on a wide range of maternal behaviors and experiences before, during, and after pregnancy. PRAMS surveys currently are administered by 37 states and New York City. The surveys consist of monthly stratified random samples of 100--300 women with recent live births recorded in state birth certificate registries. Selected mothers are mailed a questionnaire 2--6 months after delivery, and those who do not respond by mail are contacted by telephone.*

To assess seasonal and 2009 H1N1 influenza vaccination coverage among pregnant women, supplemental questions were added to the PRAMS survey. During the 2009--10 influenza season, 30 states agreed to participate in the supplemental influenza assessment. For this analysis, 10 states? were selected that submitted their data to CDC by September 15 and had a response rate ≥65%. Included in this analysis were 6,225 women with non-missing data regarding seasonal influenza vaccination who had live births during September 1, 2009--March 12, 2010, and 5,112 women with non-missing data regarding 2009 H1N1 vaccination who had live births during October 1, 2009--March 12, 2010. In addition, to compare seasonal and 2009 H1N1 vaccination coverage within the same sample of women, data for the 5,052 women with complete data for both vaccinations who had live births during October 1, 2009--March 12, 2010, were analyzed. The 2009 H1N1 vaccination became available on October 5, 2009.

PRAMS data were analyzed to estimate seasonal and 2009 H1N1 influenza vaccination coverage; 95% confidence intervals (CIs) and Wald chi-square tests were used to assess statistically significant associations. In the seasonal influenza sample, participants were asked, "Since September 2009, did you get a seasonal flu shot?" and "At any time during your most recent pregnancy, did a doctor, nurse, or other health-care worker offer you a seasonal flu shot or tell you to get one?" Participants also were asked, "During your most recent pregnancy, did you get an H1N1 flu shot?" and "At any time during your most recent pregnancy, did a doctor, nurse, or other health-care worker offer you an H1N1 flu shot or tell you to get one?" Participants who did not receive seasonal or 2009 H1N1 vaccinations were asked to select any reasons that applied to them from a list of reasons for not receiving the vaccinations. The data were weighted to adjust for complex survey design and nonresponse. Nearly all (98.9%) PRAMS respondents who received the influenza supplement on the questionnaire also responded to the influenza questions.

Combining the data from all 10 states included in this analysis, 50.7% (state median: 50.7%; range: 36.6%--68.3%) of the 6,225 women in the seasonal influenza sample reported receiving the seasonal influenza vaccination since September 2009, and 46.6% (state median: 45.5%; range: 26.9%--72.4%) of the 5,112 women in the 2009 H1N1 sample reported receiving the 2009 H1N1 influenza vaccination while pregnant (Table). To compare seasonal and 2009 H1N1 vaccination coverage within the same sample, data for the 5,052 women with live births during October 1, 2009--March 12, 2010, and complete influenza vaccination data were analyzed; 66.0% received at least one of the vaccinations, and 34.0% received neither. Among the 5,052 women, 34.1% received both influenza vaccinations during their pregnancy, 19.7% received only the seasonal vaccination, and 12.2% received only the 2009 H1N1 vaccination (Table).

Large percentages of women reported that their health-care provider had offered or recommended the seasonal influenza vaccination (67.4%) and 2009 H1N1 vaccination (75.2%). Among those whose health-care provider offered or recommended the seasonal vaccination, larger proportions reported receiving the vaccination than among those whose health-care provider did not offer or recommend it (65.8% versus 19.6%) (RR = 3.3; CI = 2.9--3.9). Among those whose health-care provider offered or recommended the 2009 H1N1 vaccination, larger proportions reported receiving the vaccination than among those whose health-care provider did not offer or recommend it (60.1% versus 5.9%) (RR = 10.1; CI = 7.7--14.3).

Among 2,290 women who received the 2009 H1N1 vaccination, 50.9% reported receiving it at the office of their obstetrician/gynecologist, and 25.7% received it at a health department or community clinic (Table). Among 2,994 who did not receive the seasonal influenza vaccination, 47.7% cited safety concerns for their baby, and 45.2% cited safety concerns for themselves. Among 2,602 who did not receive the 2009 H1N1 vaccination, 63.6% cited safety concerns for their baby, and 61.4% cited safety concerns for themselves (Table).

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http://www.cdc.gov/mmwr/preview/mmwr...cid=mm5947a1_x