TY - JOUR
T1 - The effect of influenza vaccination on birth outcomes in a cohort of pregnant women in Lao PDR, 2014-2015
AU - Olsen, Sonja J.
AU - Mirza, Sara A.
AU - Vonglokham, Phouvanh
AU - Khanthamaly, Viengphone
AU - Chitry, Bounlap
AU - Pholsena, Vathsana
AU - Chitranonh, Visith
AU - Omer, Saad B.
AU - Moen, Ann
AU - Bresee, Joseph S.
AU - Corwin, Andrew
AU - Xeuatvongsa, Anonh
N1 - Publisher Copyright:
© 2016 Published by Oxford University Press for the Infectious Diseases Society of America 2016.
PY - 2016/8/15
Y1 - 2016/8/15
N2 - Background. Some studies suggest that maternal influenza vaccination can improve birth outcomes. However, there are limited data from tropical settings, particularly Southeast Asia. We conducted an observational study in Laos to assess the effect of influenza vaccination in pregnant women on birth outcomes. Methods. We consented and enrolled a cohort of pregnant woman who delivered babies at 3 hospitals during April 2014-February 2015. We collected demographic and clinical information on mother and child. Influenza vaccination status was ascertained by vaccine card. Primary outcomes were the proportion of live births born small for gestational age (SGA) or preterm and mean birth weight. Multivariate models controlled for differences between vaccinated and unvaccinated women and influenza virus circulation. Results. We enrolled 5103 women (2172 [43%] were vaccinated). Among the 4854 who had a live birth, vaccinated women were statistically significantly less likely than unvaccinated women to have an infant born preterm during the period of high influenza virus circulation (risk ratio [RR] = 0.56, 95% confidence interval [CI],. 45-.70), and the effect remained after adjusting for covariates (adjusted RR, 0.69; 95% CI,. 55-.87). There was no effect of vaccine on SGA or mean birth weight. The population-prevented fraction was 18.0%. Conclusions. In this observational study, we found indirect evidence of influenza vaccine safety during pregnancy, and women who received vaccine had a reduced risk of delivering a preterm infant during times of high influenza virus circulation. Vaccination may prevent 1 in 5 preterm births that occur during periods of high influenza circulation.
AB - Background. Some studies suggest that maternal influenza vaccination can improve birth outcomes. However, there are limited data from tropical settings, particularly Southeast Asia. We conducted an observational study in Laos to assess the effect of influenza vaccination in pregnant women on birth outcomes. Methods. We consented and enrolled a cohort of pregnant woman who delivered babies at 3 hospitals during April 2014-February 2015. We collected demographic and clinical information on mother and child. Influenza vaccination status was ascertained by vaccine card. Primary outcomes were the proportion of live births born small for gestational age (SGA) or preterm and mean birth weight. Multivariate models controlled for differences between vaccinated and unvaccinated women and influenza virus circulation. Results. We enrolled 5103 women (2172 [43%] were vaccinated). Among the 4854 who had a live birth, vaccinated women were statistically significantly less likely than unvaccinated women to have an infant born preterm during the period of high influenza virus circulation (risk ratio [RR] = 0.56, 95% confidence interval [CI],. 45-.70), and the effect remained after adjusting for covariates (adjusted RR, 0.69; 95% CI,. 55-.87). There was no effect of vaccine on SGA or mean birth weight. The population-prevented fraction was 18.0%. Conclusions. In this observational study, we found indirect evidence of influenza vaccine safety during pregnancy, and women who received vaccine had a reduced risk of delivering a preterm infant during times of high influenza virus circulation. Vaccination may prevent 1 in 5 preterm births that occur during periods of high influenza circulation.
KW - Laos
UR - http://www.scopus.com/inward/record.url?scp=84982182160&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84982182160&partnerID=8YFLogxK
U2 - 10.1093/cid/ciw290
DO - 10.1093/cid/ciw290
M3 - Review article
C2 - 27143672
AN - SCOPUS:84982182160
SN - 1058-4838
VL - 63
SP - 487
EP - 494
JO - Clinical Infectious Diseases
JF - Clinical Infectious Diseases
IS - 4
ER -