What are the healthcare cost savings possible with an RSV vaccine given to pregnant mothers to protect their newborn children? In an oral abstract presented at IDWeek 2023, titled Potential Public Health Impact of Bivalent Respiratory Syncytial Virus Prefusion F Maternal Vaccine for Prevention of RSV among US Infants, Amy W. Law, PharmD, director, global value & evidence, Pfizer, Inc., made the case that a medication currently in FDA review would result in substantial economic and clinical outcome benefits.

Dr. Law said that RSV is a leading cause of lower respiratory tract illness (LRTI) among young children. A bivalent stabilized prefusion F subunit vaccine (RSVpreF) for pregnant people to protect their infants against RSV-LRTI is currently under review by the FDA. “We evaluated the potential public health impact, measured as the reduction in clinical outcomes and economic costs, of maternal vaccination with RSVpreF for the prevention of RSV-LRTI among U.S. infants,” she said.

To carry out the analysis, Dr. Law explained, a cohort model was employed to depict clinical outcomes and economic costs of RSV-LRTI from birth to age 1 year, lifetime consequences of premature death, and impact of maternal vaccination with RSVpreF among infants. Clinical outcomes were projected (monthly) based on infant age, gestational age in weeks (wGA) at birth, RSV disease and fatality rates, and mother’s vaccination status, and included cases of medically attended RSV-LRTI and RSV-LRTI deaths.

Vaccine effectiveness, she said, was derived from interim trial analyses and was assumed to vary by clinical presentation (hospital vs. ambulatory), timing of vaccine administration relative to birth, and wGA at birth. Economic costs were generated based on cases and corresponding unit costs. The public health impact of RSVpreF was evaluated assuming year-round use and 100% uptake.

Summarizing the results, without use of maternal RSVpreF vaccine, 48,246 hospitalizations, 144,495 emergency department encounters, and 399,313 outpatient clinic visits are projected to occur annually among the U.S. birth cohort of 3.7 million infants aged younger than 12 months, Dr. Law said. Maternal vaccination with RSVpreF resulted in a reduction of 24,520 hospitalizations, 45,957 emergency encounters, and 128,745 outpatient clinic visits, corresponding with a decrease in direct medical costs equal to $691.8 million and indirect (nonmedical) costs equal to $110.0 million.

Dr. Law concluded, “Results from this evaluation indicate that maternal vaccination with RSVpreF would substantially reduce the clinical and economic burden of RSV-LRTI in infants.” These results may be conservative, she added, “as we did not include potential for reductions in outcomes such as maternal RSV disease, household transmission, and long-term sequelae, such as asthma.”