Immunogenicity and efficacy of influenza immunization during pregnancy: recent and ongoing studies.

Pregnant women and young infants are at increased risk from influenza. The World Health Organization and public health guidelines from Australia, Canada, and the United States recommend immunizing pregnant women with trivalent inactivated influenza vaccine. However, there are multiple barriers to the uptake of this recommendation. Additionally, current vaccines are not licensed for infants <6 months of age. Immunizing pregnant women would provide protection to both mothers and infants. The Bill & Melinda Gates Foundation (BMGF) and the National Institute of Allergy and Infectious Diseases (NIAID) are trying to address some of the issues associated with maternal immunization, which could be an effective intervention in both high- and low-resource settings to combat the significant maternal and infant morbidity and mortality due to influenza. BMGF and NIAID efforts are complementary to each other, focusing on evaluating the immunogenicity, efficacy, and safety of influenza vaccines during pregnancy; and the potential effect of maternal immunization on outcomes in infants in low-resource populations.

Adegbola R ，Nesin M ，Wairagkar N 《-》

Translating vaccine policy into action: a report from the Bill & Melinda Gates Foundation Consultation on the prevention of maternal and early infant influenza in resource-limited settings.

Immunization of pregnant women against influenza is a promising strategy to protect the mother, fetus, and young infant from influenza-related diseases. The burden of influenza during pregnancy, the vaccine immunogenicity during this period, and the robust influenza vaccine safety database underpin recommendations that all pregnant women receive the vaccine to decrease complications of influenza disease during their pregnancies. Recent data also support maternal immunization for the additional purpose of preventing disease in the infant during the first six months of life. In April 2012, the WHO Strategic Advisory Group of Experts (SAGE) on Immunization recommended revisions to the WHO position paper on influenza vaccines. For the first time, SAGE recommended pregnant women should be made the highest priority for inactivated seasonal influenza vaccination. However, the variable maternal influenza vaccination coverage in countries with pre-existing maternal influenza vaccine recommendations underscores the need to understand and to address the discrepancy between recommendations and implementation success. We present the outcome of a multi-stakeholder expert consultation on inactivated influenza vaccination in pregnancy. The creation and implementation of vaccine policies and regulations require substantial resources and capacity. As with all public health interventions, the existence of perceived and real risks of vaccination will necessitate effective and transparent risk communication. Potential risk allocation and sharing mechanisms should be addressed by governments, vaccine manufacturers, and other stakeholders. In resource-limited settings, vaccine-related issues concerning supply, formulation, regulation, evidence evaluation, distribution, cost-utility, and post-marketing safety surveillance need to be addressed. Lessons can be learned from the Maternal and Neonatal Tetanus Elimination Initiative as well as efforts to increase vaccine coverage among pregnant women during the 2009 influenza pandemic. We conclude with an analysis of data gaps and necessary activities to facilitate implementation of maternal influenza immunization programs in resource-limited settings.

Ortiz JR ，Neuzil KM ，Ahonkhai VI ，Gellin BG ，Salisbury DM ，Read JS ，Adegbola RA ，Abramson JS ... -  《-》

Influenza immunization during pregnancy: US regulatory perspective.

Maternal immunization with inactivated influenza vaccines is an important public health strategy to protect mothers and young infants from the serious complications of influenza. Although not contraindicated in pregnant women, currently US-licensed influenza vaccines are not specifically labeled for use during pregnancy. Several postmarketing initiatives are ongoing to obtain maternal and infant safety and immunogenicity data on US-licensed inactivated influenza vaccines used in pregnant women. The Food and Drug Administration is revising its pregnancy labeling regulations to improve the characterization and communication of risks of drugs and biologics used during pregnancy. To obtain a specifically labeled indication for use of an influenza vaccine during pregnancy, adequate and well-controlled prelicensure studies are needed to obtain data on the product's safety and effectiveness and to demonstrate protection of the mother and/or infant against influenza illness.

Marshall V ，Gruber M 《-》

Safety of influenza vaccines in pregnant women.

Prevention of influenza in pregnant women and their newborns through maternal immunization is a safe and effective intervention during seasonal epidemics and a priority during a pandemic. While influenza vaccination of pregnant women has been routine in the United States since the 1950s, coverage rates increased significantly only after the 2009 H1N1 influenza pandemic. Epidemiologic and clinical studies support the safety of inactivated influenza vaccines in pregnant women and their infants. Safety barriers to the use of vaccines during pregnancy can be addressed through research, active surveillance, and education.

Munoz FM 《-》

Safety of influenza immunization during pregnancy for the fetus and the neonate.

Since the 1960s, pregnant women in the United States have been recommended to receive influenza vaccine. A maternal concern about the possibility of adverse fetal and neonatal outcomes after the vaccination of pregnant women has been cited as a reason for low maternal influenza vaccination coverage. Recent research has identified benefits to the fetus and neonate after maternal influenza vaccination that have prompted efforts to increase coverage in pregnant women. There is a long history of research findings that highlight the safety of vaccinating pregnant women. This review summarizes nearly 40 years of research on influenza vaccination of pregnant women and the lack of association with adverse fetal or neonatal outcomes. Future research should focus on vaccinations that are given in the first trimester of pregnancy and on product-specific analyses to account for differences in manufacturing processes.

Bednarczyk RA ，Adjaye-Gbewonyo D ，Omer SB 《-》