Pregnant women & vaccines against emerging epidemic threats: Ethics guidance for preparedness, research, and response

Zika virus, influenza, and Ebola have called attention to the ways in which infectious disease outbreaks can severely – and at times uniquely – affect the health interests of pregnant women and their offspring. These examples also highlight the critical need to proactively consider pregnant women and their offspring in vaccine research and response efforts to combat emerging and re-emerging infectious diseases. Historically, pregnant women and their offspring have been largely excluded from research agendas and investment strategies for vaccines against epidemic threats, which in turn can lead to exclusion from future vaccine campaigns amidst outbreaks. This state of affairs is profoundly unjust to pregnant women and their offspring, and deeply problematic from the standpoint of public health. To ensure that the needs of pregnant women and their offspring are fairly addressed, new approaches to public health preparedness, vaccine research and development, and vaccine delivery are required. This Guidance offers 22 concrete recommendations that provide a roadmap for the ethically responsible, socially just, and respectful inclusion of the interests of pregnant women in the development and deployment of vaccines against emerging pathogens. The Guidance was developed by the Pregnancy Research Ethics for Vaccines, Epidemics, and New Technologies (PREVENT) Working Group – a multidisciplinary, international team of 17 experts specializing in bioethics, maternal immunization, maternal-fetal medicine, obstetrics, pediatrics, philosophy, public health, and vaccine research and policy – in consultation with a variety of external experts and stakeholders.Fil: Krubiner, Carleigh B.. University Johns Hopkins; Estados UnidosFil: Faden, Ruth R.. University Johns Hopkins; Estados UnidosFil: Karron, Ruth A.. University Johns Hopkins; Estados UnidosFil: Little, Margaret O.. University Of Georgetown; Estados UnidosFil: Lyerly, Anne D.. University of North Carolina; Estados UnidosFil: Abramson, Jon S.. University Wake Forest; Estados UnidosFil: Beigi, Richard H.. Magee-Womens Hospital of University of Pittsburgh Medical Center; Estados UnidosFil: Cravioto, Alejandro R.. Universidad Nacional Autónoma de México; MéxicoFil: Durbin, Anna P.. University Johns Hopkins; Estados UnidosFil: Gellin, Bruce G.. Sabin Vaccine Institute; Estados UnidosFil: Gupta, Swati B.. IAVI; Estados UnidosFil: Kaslow, David C.. PATH; Estados UnidosFil: Kochhar, Sonali. Global Healthcare Consulting; IndiaFil: Luna, Florencia. Facultad Latinoamericana de Ciencias Sociales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Saenz, Carla. Pan American Health Organization; Estados UnidosFil: Sheffield, Jeanne S.. University Johns Hopkins; Estados UnidosFil: Tindana, Paulina O.. Navrongo Health Research Centre; GhanaFil: The Prevent Working Group. No especifíca

Informing randomized clinical trials of respiratory syncytial virus vaccination during pregnancy to prevent recurrent childhood wheezing : A sample size analysis

Background: Early RSV illness is associated with wheeze-associated disorders in childhood. Candidate respiratory syncytial virus (RSV) vaccines may prevent acute RSV illness in infants. We investigated the feasibility of maternal RSV vaccine trials to demonstrate reductions in recurrent childhood wheezing in general paediatric populations. Methods: We calculated vaccine trial effect sizes that depended on vaccine efficacy, allocation ratio, rate of early severe RSV illness, risk of recurrent wheezing at age 3, and increased risk of RSV infection on recurrent wheezing. Model inputs came from systematic reviews and meta-analyses. For each combination of inputs, we estimated the sample size required to detect the effect of vaccination on recurrent wheezing. Results: There were 81 scenarios with 1:1 allocation ratio. Risk ratios between vaccination and recurrent wheezing ranged from 0.9 to 1.0 for 70% of the scenarios. Among the 57 more plausible scenarios, the lowest sample size required to detect significant reductions in recurrent wheezing was 6196 mother-infant pairs per trial arm; however, 75% and 47% of plausible scenarios required >31,060 and >100,000 mother-infant pairs per trial arm, respectively. Studies with asthma endpoints at age 5 will likely need to be larger. Discussion: Clinical efficacy trials of candidate maternal RSV vaccines undertaken for licensure are unlikely to demonstrate an effect on recurrent wheezing illness due to the large sample sizes likely needed to demonstrate a significant effect. Further efforts are needed to plan for alternative study designs to estimate the impact of maternal RSV vaccine programs on recurrent childhood wheezing in general populations