The importance of maternal immunization

Almost 700,000 children under one month die each year due to infectious diseases, such as pneumonia or sepsis. These diseases contribute to approximately 28% of mortality in children under one year of age.

While routine infant vaccination has significantly decreased infection-related mortality in children, newborns are reliant on maternal antibodies during this period of greatest vulnerability. Infections may also be associated with stillbirths, preterm and intrapartum complications for the mother and the neonate; therefore, early prevention is key to making progress in this area.

Making way for maternal immunization

Maternal Immunization is increasingly being recognized as a unique approach to potentially confer protection via passive transfer of maternal antibodies across the placenta to protect infants during their first few months of life. The Bill & Melinda Gates Foundation launched an initiative to develop MI focused on five infectious diseases, three with vaccines already available—influenza, pertussis and tetanus—and two for which vaccines specifically designed for MI are currently in clinical development—respiratory syncytial virus (RSV) and group B Streptococcus (GBS).

Now it seems like development of these vaccines is a given. But that wasn’t always the case

Development and licensure of safe and effective interventions for use during pregnancy require extensive risk-benefit assessments, prior to regulatory approval for licensure. In the past, regulators have primarily focused on limiting inclusion of pregnant women in clinical trials to those who are at increased risk. With vaccines now being effectively used to protect pregnant women and young infants against infections such as tetanus, seasonal and pandemic influenza, and pertussis, the paradigm is shifting to explore the untapped potential of vaccination during pregnancy to confer protection for both mothers and babies.

FDA advisory meeting on the use of vaccines in pregnant women to protect newborn babies

A milestone Vaccines and Biological Products Advisory Committee meeting was convened by the Food and Drug Administration (FDA) advisory meeting (VRBPAC) on November 13, 2015. The FDA held this public discussion to review some of the general considerations for the development of vaccines with pregnancy indications, and to outline requirements for the path to licensure for vaccines intended for use in pregnancy to prevent diseases in infants. Key topics included the use of surrogate endpoints for diseases that require large efficacy studies, as well as licensure studies including data from low and middle-income countries (LMICs). The Bill & Melinda Gates Foundation was invited to set the stage for this discussion. The meeting reviewed the substantial progress that has been made across different populations to strengthen the benefit-risk assessment of MI, thereby advancing the global MI vaccine development and implementation agenda. Various stakeholders recognized the leadership role of the foundation in this area including advancing MI on the global health agenda to address child mortality in LMICs.

Why is this important?

The FDA is frequently referenced regarding global reference standards for path to licensure criteria for new interventions. It plays a critical role in enabling the clinical development of safe and effective interventions in various geographies, and in particular for pregnant women.

Shortly after the VRBPAC meeting the FDA for the first time approved the advancement of a Respiratory Syncytial Virus (RSV) vaccine to phase 3 clinical development. This could be the first vaccine advanced to seek an indication for use in pregnancy.