{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T05:32:55Z","timestamp":1787031175224,"version":"build-2736575974"},"reference-count":54,"publisher":"American Society of Tropical Medicine and Hygiene","issue":"1","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,1,7]]},"abstract":"<jats:title>ABSTRACT.<\/jats:title>\n                  <jats:p>\n                    Although maternal influenza vaccination can prevent influenza morbidity and mortality, data are limited on vaccine efficacy\/effectiveness against severe disease in low- and middle-income countries (LMICs) at the community level. We evaluated the impact of maternal influenza vaccination on maternal influenza disease severity across seasons in a rural subtropical area in South Asia by analyzing data from a vaccine clinical trial conducted between 2011 and 2014 in Sarlahi District, Nepal. Participants were randomized 1:1 to trivalent seasonal influenza vaccine or saline placebo and followed through 180 days postpartum. Weekly household-based active respiratory surveillance was conducted; if participants reported fever and respiratory symptoms, a midnasal swab was collected and tested for influenza using reverse transcription polymerase chain reaction. Among 3,693 participants (\n                    <jats:italic>n<\/jats:italic>\n                    = 1,847 vaccine;\n                    <jats:italic>n<\/jats:italic>\n                    = 1,846 placebo), we detected 75 influenza illness episodes, including 40 with care seeking and 22 with fever for more than 3 days. Using proportional hazards regression, maternal influenza vaccination reduced the estimated hazard of influenza-associated care-seeking visits and fever for more than 3 days by 36% and 21%, respectively, compared with placebo; however, these differences were not statistically significant. The estimated numbers needed to vaccinate to prevent one influenza illness with care seeking and fever for more than 3 days were 224 and 785, respectively, at 270 days postvaccination. These findings suggest that maternal immunization may reduce the risk of moderate influenza illness among pregnant\/postpartum individuals in LMICs, particularly in rural areas where access to care is limited.\n                  <\/jats:p>","DOI":"10.4269\/ajtmh.25-0065","type":"journal-article","created":{"date-parts":[[2025,11,6]],"date-time":"2025-11-06T17:04:01Z","timestamp":1762448641000},"page":"92-100","source":"Crossref","is-referenced-by-count":1,"title":["Impact of Influenza Vaccination during Pregnancy on Maternal Influenza Disease Severity in Rural Nepal"],"prefix":"10.4269","volume":"114","author":[{"given":"Collrane","family":"Frivold","sequence":"first","affiliation":[{"name":"Department of Medicine, University of Washington, Seattle, Washington;"},{"name":"Department of Epidemiology, University of Washington, Seattle, Washington;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joanne","family":"Katz","sequence":"additional","affiliation":[{"name":"Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tsering Pema","family":"Lama","sequence":"additional","affiliation":[{"name":"Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland;"},{"name":"Nepal Nutrition Intervention Project\u2014Sarlahi, Kathmandu, Nepal;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"James M.","family":"Tielsch","sequence":"additional","affiliation":[{"name":"Department of Global Health, George Washington University, Washington, District of Columbia;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Subarna K.","family":"Khatry","sequence":"additional","affiliation":[{"name":"Nepal Nutrition Intervention Project\u2014Sarlahi, Kathmandu, Nepal;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Steven C.","family":"LeClerq","sequence":"additional","affiliation":[{"name":"Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland;"},{"name":"Nepal Nutrition Intervention Project\u2014Sarlahi, Kathmandu, Nepal;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marco","family":"Carone","sequence":"additional","affiliation":[{"name":"Department of Biostatistics, University of Washington, Seattle, Washington;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Grace","family":"John-Stewart","sequence":"additional","affiliation":[{"name":"Department of Medicine, University of Washington, Seattle, Washington;"},{"name":"Department of Epidemiology, University of Washington, Seattle, Washington;"},{"name":"Department of Global Health, University of Washington, Seattle, Washington;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christine M.","family":"Khosropour","sequence":"additional","affiliation":[{"name":"Department of Epidemiology, University of Washington, Seattle, Washington;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Janet A.","family":"Englund","sequence":"additional","affiliation":[{"name":"Seattle Children\u2019s Research Institute, Seattle, Washington"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Helen Y.","family":"Chu","sequence":"additional","affiliation":[{"name":"Department of Medicine, University of Washington, Seattle, Washington;"},{"name":"Department of Epidemiology, University of Washington, Seattle, Washington;"},{"name":"Department of Global Health, University of Washington, Seattle, Washington;"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"2795","reference":[{"key":"b1","series-title":"Wkly Epidemiol Rec","first-page":"185","article-title":"Vaccines against influenza WHO position paper\u2014May 2022","volume":"97","year":"2022"},{"key":"b2","article-title":"Influenza (Seasonal).","year":"2022"},{"key":"b3","series-title":"BMC Infect Dis","first-page":"683","article-title":"Pregnancy as a risk factor for severe influenza infection: An individual participant data meta-analysis","volume":"19","author":"Mertz","year":"2019"},{"key":"b4","series-title":"PLoS Med","first-page":"e1000441","article-title":"Maternal influenza immunization and reduced likelihood of prematurity and small for gestational age births: A retrospective cohort study","volume":"8","author":"Omer","year":"2011"},{"key":"b5","series-title":"CMAJ","first-page":"645","article-title":"Neonatal outcomes after influenza immunization during pregnancy: A randomized controlled trial","volume":"184","author":"Steinhoff","year":"2012"},{"key":"b6","series-title":"Lancet Infect Dis","first-page":"981","article-title":"Year-round influenza immunisation during pregnancy in Nepal: A phase 4, randomised, placebo-controlled trial","volume":"17","author":"Steinhoff","year":"2017"},{"key":"b7","series-title":"J Glob Health","first-page":"020421","article-title":"Global mortality associated with seasonal influenza epidemics: New burden estimates and predictors from the GLaMOR Project","volume":"9","author":"Paget","year":"2022"},{"key":"b8","series-title":"Lancet","first-page":"1285","article-title":"Estimates of global seasonal influenza-associated respiratory mortality: A modelling study","volume":"391","author":"Iuliano","year":"2018"},{"key":"b9","series-title":"Vaccine","first-page":"521","article-title":"Pregnancy as a risk factor for severe outcomes from influenza virus infection: A systematic review and meta-analysis of observational studies","volume":"35","author":"Mertz","year":"2017"},{"key":"b10","article-title":"Final Annexes\u2013Vaccines against Influenza: WHO Position Paper\u2014May 2022.","year":"2022"},{"key":"b11","series-title":"Influenza Other Respir Viruses","first-page":"254","article-title":"Seasonal influenza vaccine policy, use and effectiveness in the tropics and subtropics\u2014A systematic literature review","volume":"10","author":"Hirve","year":"2016"},{"key":"b12","series-title":"Vaccine","first-page":"4568","article-title":"Maternal immunization in Malawi: A mixed methods study of community perceptions, programmatic considerations, and recommendations for future planning","volume":"37","author":"Fleming","year":"2019"},{"key":"b13","series-title":"BMC Pregnancy Childbirth","first-page":"155","article-title":"Incidence of influenza virus infection among pregnant women: A systematic review","volume":"17","author":"Katz","year":"2017"},{"key":"b14","series-title":"BMC Pregnancy Childbirth","first-page":"40","article-title":"Designs of two randomized, community-based trials to assess the impact of influenza immunization during pregnancy on respiratory illness among pregnant women and their infants and reproductive outcomes in rural Nepal","volume":"15","author":"Tielsch","year":"2015"},{"key":"b15","series-title":"Diagn Microbiol Infect Dis","first-page":"305","article-title":"Molecular characterization of influenza viruses from women and infants in Sarlahi, Nepal","volume":"93","author":"Kuypers","year":"2019"},{"key":"b16","series-title":"Stat Med","first-page":"1461","article-title":"A comparison of different methods to adjust survival curves for confounders","volume":"42","author":"Denz","year":"2023"},{"key":"b17","series-title":"J Chronic Dis","first-page":"669","article-title":"Corrected group prognostic curves and summary statistics","volume":"35","author":"Chang","year":"1982"},{"key":"b18","series-title":"J Chronic Dis","first-page":"437","article-title":"Adjusted survival curve estimation using covariates","volume":"35","author":"Makuch","year":"1982"},{"key":"b19","series-title":"J Clin Epidemiol","first-page":"46","article-title":"Absolute risk reductions and numbers needed to treat can be obtained from adjusted survival models for time-to-event outcomes","volume":"63","author":"Austin","year":"2010"},{"key":"b20","series-title":"Lancet Reg Health Am","first-page":"100530","article-title":"Number needed to vaccinate with a COVID-19 booster to prevent a COVID-19-associated hospitalization during SARS-CoV-2 Omicron BA.1 variant predominance, December 2021\u2013February 2022, VISION Network: A retrospective cohort study","volume":"23","author":"Adams","year":"2023"},{"key":"b21","series-title":"BMJ","first-page":"1492","article-title":"Calculating the number needed to treat for trials where the outcome is time to an event","volume":"319","author":"Altman","year":"1999"},{"key":"b22","series-title":"RStudio: Integrated Development Environment for R","year":"2021"},{"key":"b23","article-title":"Global Influenza Programme: Respiratory Viruses.","year":"2025"},{"key":"b24","series-title":"Cochrane Database Syst Rev","first-page":"CD001269","article-title":"Vaccines for preventing influenza in healthy adults","volume":"2","author":"Demicheli","year":"2018"},{"key":"b25","series-title":"Pediatrics","first-page":"467","article-title":"Childhood influenza: Number needed to vaccinate to prevent 1 hospitalization or outpatient visit","volume":"120","author":"Lewis","year":"2007"},{"key":"b26","series-title":"Lancet Infect Dis","first-page":"1026","article-title":"Maternal immunisation with trivalent inactivated influenza vaccine for prevention of influenza in infants in Mali: A prospective, active-controlled, observer-blind, randomised phase 4 trial","volume":"16","author":"Tapia","year":"2016"},{"key":"b27","series-title":"N Engl J Med","first-page":"918","article-title":"Influenza vaccination of pregnant women and protection of their infants","volume":"371","author":"Madhi","year":"2014"},{"key":"b1","series-title":"Wkly Epidemiol Rec","first-page":"185","article-title":"Vaccines against influenza WHO position paper\u2014May 2022","volume":"97","year":"2022"},{"key":"b2","article-title":"Influenza (Seasonal).","year":"2022"},{"key":"b3","series-title":"BMC Infect Dis","first-page":"683","article-title":"Pregnancy as a risk factor for severe influenza infection: An individual participant data meta-analysis","volume":"19","author":"Mertz","year":"2019"},{"key":"b4","series-title":"PLoS Med","first-page":"e1000441","article-title":"Maternal influenza immunization and reduced likelihood of prematurity and small for gestational age births: A retrospective cohort study","volume":"8","author":"Omer","year":"2011"},{"key":"b5","series-title":"CMAJ","first-page":"645","article-title":"Neonatal outcomes after influenza immunization during pregnancy: A randomized controlled trial","volume":"184","author":"Steinhoff","year":"2012"},{"key":"b6","series-title":"Lancet Infect Dis","first-page":"981","article-title":"Year-round influenza immunisation during pregnancy in Nepal: A phase 4, randomised, placebo-controlled trial","volume":"17","author":"Steinhoff","year":"2017"},{"key":"b7","series-title":"J Glob Health","first-page":"020421","article-title":"Global mortality associated with seasonal influenza epidemics: New burden estimates and predictors from the GLaMOR Project","volume":"9","author":"Paget","year":"2022"},{"key":"b8","series-title":"Lancet","first-page":"1285","article-title":"Estimates of global seasonal influenza-associated respiratory mortality: A modelling study","volume":"391","author":"Iuliano","year":"2018"},{"key":"b9","series-title":"Vaccine","first-page":"521","article-title":"Pregnancy as a risk factor for severe outcomes from influenza virus infection: A systematic review and meta-analysis of observational studies","volume":"35","author":"Mertz","year":"2017"},{"key":"b10","article-title":"Final Annexes\u2013Vaccines against Influenza: WHO Position Paper\u2014May 2022.","year":"2022"},{"key":"b11","series-title":"Influenza Other Respir Viruses","first-page":"254","article-title":"Seasonal influenza vaccine policy, use and effectiveness in the tropics and subtropics\u2014A systematic literature review","volume":"10","author":"Hirve","year":"2016"},{"key":"b12","series-title":"Vaccine","first-page":"4568","article-title":"Maternal immunization in Malawi: A mixed methods study of community perceptions, programmatic considerations, and recommendations for future planning","volume":"37","author":"Fleming","year":"2019"},{"key":"b13","series-title":"BMC Pregnancy Childbirth","first-page":"155","article-title":"Incidence of influenza virus infection among pregnant women: A systematic review","volume":"17","author":"Katz","year":"2017"},{"key":"b14","series-title":"BMC Pregnancy Childbirth","first-page":"40","article-title":"Designs of two randomized, community-based trials to assess the impact of influenza immunization during pregnancy on respiratory illness among pregnant women and their infants and reproductive outcomes in rural Nepal","volume":"15","author":"Tielsch","year":"2015"},{"key":"b15","series-title":"Diagn Microbiol Infect Dis","first-page":"305","article-title":"Molecular characterization of influenza viruses from women and infants in Sarlahi, Nepal","volume":"93","author":"Kuypers","year":"2019"},{"key":"b16","series-title":"Stat Med","first-page":"1461","article-title":"A comparison of different methods to adjust survival curves for confounders","volume":"42","author":"Denz","year":"2023"},{"key":"b17","series-title":"J Chronic Dis","first-page":"669","article-title":"Corrected group prognostic curves and summary statistics","volume":"35","author":"Chang","year":"1982"},{"key":"b18","series-title":"J Chronic Dis","first-page":"437","article-title":"Adjusted survival curve estimation using covariates","volume":"35","author":"Makuch","year":"1982"},{"key":"b19","series-title":"J Clin Epidemiol","first-page":"46","article-title":"Absolute risk reductions and numbers needed to treat can be obtained from adjusted survival models for time-to-event outcomes","volume":"63","author":"Austin","year":"2010"},{"key":"b20","series-title":"Lancet Reg Health Am","first-page":"100530","article-title":"Number needed to vaccinate with a COVID-19 booster to prevent a COVID-19-associated hospitalization during SARS-CoV-2 Omicron BA.1 variant predominance, December 2021\u2013February 2022, VISION Network: A retrospective cohort study","volume":"23","author":"Adams","year":"2023"},{"key":"b21","series-title":"BMJ","first-page":"1492","article-title":"Calculating the number needed to treat for trials where the outcome is time to an event","volume":"319","author":"Altman","year":"1999"},{"key":"b22","series-title":"RStudio: Integrated Development Environment for R","year":"2021"},{"key":"b23","article-title":"Global Influenza Programme: Respiratory Viruses.","year":"2025"},{"key":"b24","series-title":"Cochrane Database Syst Rev","first-page":"CD001269","article-title":"Vaccines for preventing influenza in healthy adults","volume":"2","author":"Demicheli","year":"2018"},{"key":"b25","series-title":"Pediatrics","first-page":"467","article-title":"Childhood influenza: Number needed to vaccinate to prevent 1 hospitalization or outpatient visit","volume":"120","author":"Lewis","year":"2007"},{"key":"b26","series-title":"Lancet Infect Dis","first-page":"1026","article-title":"Maternal immunisation with trivalent inactivated influenza vaccine for prevention of influenza in infants in Mali: A prospective, active-controlled, observer-blind, randomised phase 4 trial","volume":"16","author":"Tapia","year":"2016"},{"key":"b27","series-title":"N Engl J Med","first-page":"918","article-title":"Influenza vaccination of pregnant women and protection of their infants","volume":"371","author":"Madhi","year":"2014"}],"container-title":["The American Journal of Tropical Medicine and Hygiene"],"original-title":[],"link":[{"URL":"https:\/\/www.ajtmh.org\/view\/journals\/tpmd\/114\/1\/article-p92.xml","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.ajtmh.org\/downloadpdf\/journals\/tpmd\/114\/1\/article-p92.xml","content-type":"text\/html","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/www.ajtmh.org\/downloadpdf\/journals\/tpmd\/114\/1\/article-p92.xml","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,1,7]],"date-time":"2026-01-07T13:53:25Z","timestamp":1767794005000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.ajtmh.org\/view\/journals\/tpmd\/114\/1\/article-p92.xml"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,1,7]]},"references-count":54,"journal-issue":{"issue":"1"},"URL":"https:\/\/doi.org\/10.4269\/ajtmh.25-0065","relation":{},"ISSN":["0002-9637","1476-1645"],"issn-type":[{"value":"0002-9637","type":"print"},{"value":"1476-1645","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,1,7]]}}}