title: Three randomized trials of maternal influenza immunization in Mali, Nepal, and South Africa: Methods and expectations.
abstract: Influenza infection in pregnancy can have adverse impacts on maternal, fetal, and infant outcomes. Influenza vaccination in pregnancy is an appealing strategy to protect pregnant women and their infants. The Bill & Melinda Gates Foundation is supporting three large, randomized trials in Nepal, Mali, and South Africa evaluating the efficacy and safety of maternal immunization to prevent influenza disease in pregnant women and their infants <6 months of age. Results from these individual studies are expected in 2014 and 2015. While the results from the three maternal immunization trials are likely to strengthen the evidence base regarding the impact of influenza immunization in pregnancy, expectations for these results should be realistic. For example, evidence from previous influenza vaccine studies - conducted in general, non-pregnant populations - suggests substantial geographic and year-to-year variability in influenza incidence and vaccine efficacy/effectiveness. Since the evidence generated from the three maternal influenza immunization trials will be complementary, in this paper we present a side-by-side description of the three studies as well as the similarities and differences between these trials in terms of study location, design, outcome evaluation, and laboratory and epidemiological methods. We also describe the likely remaining knowledge gap after the results from these trials become available along with a description of the analyses that will be conducted when the results from these individual data are pooled. Moreover, we highlight that additional research on logistics of seasonal influenza vaccine supply, surveillance and strain matching, and optimal delivery strategies for pregnant women will be important for informing global policy related to maternal influenza immunization.
authors.affiliation: Hubert Department of Global Health, Emory University Rollins School of Public Health, Atlanta, GA, USA; Department of Epidemiology, Emory University Rollins School of Public Health, Atlanta, GA, USA; Emory Vaccine Center, Atlanta, GA, USA; Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA, USA. Electronic address: somer@emory.edu.
authors.forename: Saad B
authors.initials: SB
authors.lastname: Omer
authors.affiliation: Department of Epidemiology, Emory University Rollins School of Public Health, Atlanta, GA, USA.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Richards
authors.affiliation: Medical Research Council, Respiratory and Meningeal Pathogens Research Unit, Swindon, UK; Department of Science and Technology-National Research Foundation, Vaccine-Preventable Diseases, Johannesburg, South Africa; National Institute for Communicable Diseases, The National Health Laboratory Service, Centre for Vaccines and Immunology, Johannesburg, South Africa.
authors.forename: Shabir A
authors.initials: SA
authors.lastname: Madhi
authors.affiliation: Centre pour le Développement des Vaccins, Bamako, Mali; University of Maryland School of Medicine, Center for Vaccine Development, Baltimore, MD, USA.
authors.forename: Milagritos D
authors.initials: MD
authors.lastname: Tapia
authors.affiliation: Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA; Cincinnati Children's Hospital Global Health Center, Cincinnati, OH, USA.
authors.forename: Mark C
authors.initials: MC
authors.lastname: Steinhoff
authors.affiliation: Hubert Department of Global Health, Emory University Rollins School of Public Health, Atlanta, GA, USA.
authors.forename: Anushka R
authors.initials: AR
authors.lastname: Aqil
authors.affiliation: Bill & Melinda Gates Foundation, Seattle, WA, USA.
authors.forename: Niteen
authors.initials: N
authors.lastname: Wairagkar
mesh_terms: D005260:Female; D006801:Humans; D007114:Immunization / Q000379:methods*; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D007251:Influenza, Human / Q000517:prevention & control*; D008302:Mali; D009390:Nepal; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000517:prevention & control*; D016032:Randomized Controlled Trials as Topic; D013019:South Africa
chemical_list: D007252:Influenza Vaccines
keywords: Influenza; Mali; Maternal immunization; Nepal; Pooled analyses; South Africa