tetano
Editor, Senior Moderator
Clin Infect Dis. (2013) doi: 10.1093/cid/cit750 First published online: November 26, 2013
Effectiveness of seasonal trivalent influenza vaccine for preventing influenza virus illness among pregnant women: a population-based case-control study during the 2010-2011 and 2011-2012 influenza seasons
Mark G. Thompson1,
De-Kun Li2,3,
Pat Shifflett4,
Leslie Z. Sokolow1,5,
Jeannette R. Ferber2,
Samantha Kurosky6,
Sam Bozeman4,
Sue B. Reynolds1,
Roxana Odouli2,
Michelle L. Henninger6,
Tia L. Kauffman6,
Lyndsay A. Avalos2,
Sarah Ball4,
Jennifer L. Williams7,
Stephanie A. Irving6,
David K. Shay1,
Allison L. Naleway6,
for The Pregnancy and Influenza Project Workgroup
+ Author Affiliations
1Influenza Division, Centers for Disease Control and Prevention (CDC), Atlanta, GA
2Division of Research, Kaiser Foundation Research Institute, Oakland, CA
3Department of Health Research and Policy, School of Medicine, Stanford University
4Abt Associates, Inc., Cambridge, MA
5Battelle Memorial Institute, Atlanta, GA
6Center for Health Research, Kaiser Permanente Northwest, Portland, OR
7National Center on Birth Defects and Developmental Disabilities, CDC, Atlanta, GA
Correspondence: isq8@cdc.gov
Abstract
Background. Although vaccination with trivalent inactivated influenza vaccine (TIV) is recommended for all pregnant women, no vaccine effectiveness (VE) studies of TIV in pregnant women have assessed laboratory-confirmed influenza outcomes.
Methods. We conducted a case-control study over two influenza seasons (2010-2011 and 2011-2012) among Kaiser Permanente health plan members in two metropolitan areas in California and Oregon. We compared the proportion vaccinated among 100 influenza cases (confirmed by RT-PCR) with the proportions vaccinated among 192 controls with acute respiratory illness (ARI) who tested negative for influenza and 200 controls without ARI (matched by season, site, and trimester).
Results. Among influenza cases, 42% were vaccinated during the study season compared to 58% and 63% vaccinated among influenza-negative controls and matched ARI-negative controls, respectively. The adjusted VE (95% confidence interval [CI]) of the current season vaccine against influenza A and B was 44% (5%-67%) using the influenza-negative controls and 53% (24%-72%) using the ARI-negative controls. Receipt of the prior season's vaccine, however, had an effect similar to receipt of the current season's vaccine. As such, vaccination in either or both seasons had statistically similar adjusted VE using influenza-negative controls (VE point estimates range=51%-76%) and ARI-negative controls (48%-76%).
Conclusions. Influenza vaccination reduced the risk of ARI associated with laboratory-confirmed influenza among pregnant women by over one-half, similar to VE observed among all adults during these seasons.
Received August 30, 2013.
Accepted November 4, 2013.
http://cid.oxfordjournals.org/content/early/2013/11/25/cid.cit750.short?rss=1
Effectiveness of seasonal trivalent influenza vaccine for preventing influenza virus illness among pregnant women: a population-based case-control study during the 2010-2011 and 2011-2012 influenza seasons
Mark G. Thompson1,
De-Kun Li2,3,
Pat Shifflett4,
Leslie Z. Sokolow1,5,
Jeannette R. Ferber2,
Samantha Kurosky6,
Sam Bozeman4,
Sue B. Reynolds1,
Roxana Odouli2,
Michelle L. Henninger6,
Tia L. Kauffman6,
Lyndsay A. Avalos2,
Sarah Ball4,
Jennifer L. Williams7,
Stephanie A. Irving6,
David K. Shay1,
Allison L. Naleway6,
for The Pregnancy and Influenza Project Workgroup
+ Author Affiliations
1Influenza Division, Centers for Disease Control and Prevention (CDC), Atlanta, GA
2Division of Research, Kaiser Foundation Research Institute, Oakland, CA
3Department of Health Research and Policy, School of Medicine, Stanford University
4Abt Associates, Inc., Cambridge, MA
5Battelle Memorial Institute, Atlanta, GA
6Center for Health Research, Kaiser Permanente Northwest, Portland, OR
7National Center on Birth Defects and Developmental Disabilities, CDC, Atlanta, GA
Correspondence: isq8@cdc.gov
Abstract
Background. Although vaccination with trivalent inactivated influenza vaccine (TIV) is recommended for all pregnant women, no vaccine effectiveness (VE) studies of TIV in pregnant women have assessed laboratory-confirmed influenza outcomes.
Methods. We conducted a case-control study over two influenza seasons (2010-2011 and 2011-2012) among Kaiser Permanente health plan members in two metropolitan areas in California and Oregon. We compared the proportion vaccinated among 100 influenza cases (confirmed by RT-PCR) with the proportions vaccinated among 192 controls with acute respiratory illness (ARI) who tested negative for influenza and 200 controls without ARI (matched by season, site, and trimester).
Results. Among influenza cases, 42% were vaccinated during the study season compared to 58% and 63% vaccinated among influenza-negative controls and matched ARI-negative controls, respectively. The adjusted VE (95% confidence interval [CI]) of the current season vaccine against influenza A and B was 44% (5%-67%) using the influenza-negative controls and 53% (24%-72%) using the ARI-negative controls. Receipt of the prior season's vaccine, however, had an effect similar to receipt of the current season's vaccine. As such, vaccination in either or both seasons had statistically similar adjusted VE using influenza-negative controls (VE point estimates range=51%-76%) and ARI-negative controls (48%-76%).
Conclusions. Influenza vaccination reduced the risk of ARI associated with laboratory-confirmed influenza among pregnant women by over one-half, similar to VE observed among all adults during these seasons.
Received August 30, 2013.
Accepted November 4, 2013.
http://cid.oxfordjournals.org/content/early/2013/11/25/cid.cit750.short?rss=1