Abstract
BackgroundTo better understand the impact of seasonal influenza in pregnant women we analyzed data collected during four seasons at a hospital for acute respiratory infection that specializes in treating pregnant women.MethodsThis was a single-center active surveillance study of women 15–44 years of age hospitalized for acute respiratory diseases between 2012/2013 and 2015/2016 in Moscow, Russian Federation. Women had to have been hospitalized within 7 days of the onset of symptoms. Swabs were taken within 48 h of admission, and influenza was detected by reverse transcription-polymerase chain reaction.ResultsDuring the four seasons, of the 1992 hospitalized women 1748 were pregnant. Laboratory-confirmed influenza was detected more frequently in pregnant women (825/1748; 47.2%) than non-pregnant women (58/244; 23.8%) (OR for influenza = 2.87 [95% CI, 2.10–3.92]; p < 0.001). This pattern was homogenous across seasons (p = 0.112 by test of homogeneity of equal odds). Influenza A(H1N1)pdm09 was the dominant strain in 2012/2013, A(H3N2) in 2013/2014, B/Yamagata lineage and A(H3N2) in 2014/2015, and A(H1N1)pdm09 in 2015/2016. Influenza-positive pregnant admissions went to the hospital sooner than influenza-negative pregnant admissions (p < 0.001). The risk of influenza increased by 2% with each year of age and was higher in women with underlying conditions (OR = 1.52 [95% CI, 1.16 to 1.99]). Pregnant women positive for influenza were homogeneously distributed by trimester (p = 0.37 for homogeneity; p = 0.49 for trend). Frequencies of stillbirth, delivery, preterm delivery, and caesarean delivery did not significantly differ between influenza-positive and influenza-negative hospitalized pregnant women or between subtypes/lineages.ConclusionsPregnant women are at increased risk for hospitalization due to influenza irrespective of season, circulating viruses, or trimester.
Highlights
To better understand the impact of seasonal influenza in pregnant women we analyzed data collected during four seasons at a hospital for acute respiratory infection that specializes in treating pregnant women
In 2012, the World Health Organization expanded its recommendations for seasonal influenza vaccination to all pregnant women [8]
Many of the severe cases of influenza analyzed occurred during the 2009 A(H1N1)pdm09 pandemic, when women may have been hospitalized for precautionary reasons [4]
Summary
To better understand the impact of seasonal influenza in pregnant women we analyzed data collected during four seasons at a hospital for acute respiratory infection that specializes in treating pregnant women. Pregnant women are at increased risk of severe influenza illness and influenza-related death [1,2,3] and, during all trimesters, are at increased risk of hospital admission due to influenza infection [4]. Influenza illness during pregnancy appears to be associated with increased rates of stillbirth, neonatal death, preterm delivery, and low birth weight [5,6,7]. Many of the severe cases of influenza analyzed occurred during the 2009 A(H1N1)pdm pandemic, when women may have been hospitalized for precautionary reasons [4]. Additional data are needed to evaluate and support vaccination policies for pregnant women
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
