RSV vaccine approval should be a top priority for the FDA

The calamity of March 2020 arrived two years later for pediatric units. In the fall of 2022, a tidal wave of respiratory viral illnesses sent children to emergency rooms in droves when enterovirus, respiratory syncytial virus (RSV), and influenza peaked in close succession, bombarding young children who had remained mostly unexposed to these viruses during the most acute years of the Covid pandemic.

The result was scores of infants and toddlers in need of hospitalization, greatly exceeding the capacities of our nation’s hospitals. A significant burden was placed on an already beleaguered pediatric workforce of nurses, respiratory therapists, and clinicians, and sick children were left waiting in hallways or were transported across state lines for beds. Even after the RSV and flu viral surges subsided, capacity issues have continued in pediatric hospitals, due to the ongoing pediatric behavioral health crisis, a financially driven 20% contraction of pediatric beds across the nation in the last decade, and other viral outbreaks in children, such as norovirus, whose 2023 positivity rates are already surpassing 2022’s.

Yet even in typical respiratory virus seasons, RSV is viral enemy No. 1 for children. It results in more pediatric hospitalization than any other single cause. For decades, pediatricians have remained helpless to stem the tide of newborns who are at particularly high risk for landing in the hospital while fighting this virus, often teetering on the edge of needing a breathing tube for weeks on end. Nearly 1 in 50 newborns will be hospitalized due to RSV in developed countries. Globally, RSV is the second leading cause of death during the first year of a child’s life, after malaria.

If we could wave a magic wand to ameliorate the all-but-certain confluence of a high-volume respiratory virus season, ongoing behavioral health patient needs, staffing shortages, and dwindling pediatric capacity, we would all run — not walk — to deliver this to children, families, and providers.

In fact, vaccine science has already delivered that magic wand: two highly effective RSV vaccines demonstrated to safely reduce the considerable RSV disease in the first year of life. Both are currently under review by regulators.

The first game-changing RSV vaccine is one that builds on the long-established success of Synagis, an anti-RSV monoclonal antibody. Synagis successfully reduces RSV disease in preterm and other high-risk infants, but insurance companies strictly limit eligibility because the required monthly doses are prohibitively expensive: It costs up to $1,500 per dose and requires five doses in each respiratory season. The new monoclonal antibody, Nirsevimab, already approved for use in Europe, is a more potent and longer-lasting product that can be administered once a season, making payment models more feasible for routine use.

The second RSV vaccine breakthrough was the design of an RSV surface protein in a stabilized shape that elicits the most potent neutralizing antibodies, side-stepping the issues that arose with an original RSV vaccine in the 1960s that led to more severe disease in children upon infection.

This vaccine, termed RSVpreF, takes advantage of the natural transfer of mature antibodies from the mother to the infant. The vaccine is administered to pregnant individuals in the third trimester of pregnancy, which eliminates the few weeks needed for an infant to mount an appropriate response to a vaccine at a time when they are most vulnerable.

The development of both RSV vaccines was led by pediatric researchers who understood the burden of disease for children caused by RSV.

When effective vaccines for Covid-19 were in hand and disease raged on in adult populations, the FDA and the CDC approval processes were prioritized and rapid. A completely novel Covid-19 vaccine was approved in less than a year from its inception.

But the approval processes for crucial interventions for RSV have been lumbering, even as the next respiratory viral season looms. Pfizer’s RSVpreF was discussed by the Food and Drug Administration’s Vaccines and Related Biological Products Advisory Committee on March 1 for use in older people, but the review for pregnant women is not planned until August. Nirsevimab, a product developed by AstraZenica and Sanofi, was discussed by the Advisory Committee on Immunization Practices on Feb. 23, but the result was only a statement reading, “it may not be available before October 2023.”

When we watched the panel discussions, we got the sense that the committee did not see these RSV vaccines as urgent because the virus is not a new threat. Yet, that sentiment is short-sighted given the magnitude of RSV’s impact on infants, families, pediatric providers, and the quality of care that can be delivered in our steadily declining pediatric hospital capacity. Plus, there is a long history of regulatory approvals for pediatric products being slow to materialize. (Disclosure: One of us, S.P., has provided consulting services on cytomegalovirus vaccine programs for Pfizer and Sanofi, among other vaccine companies.)

The proposed approval dates are not soon enough to ebb the next RSV wave. Last year’s surge of RSV started in late August and increased to an unprecedented high peak of cases in November. Very few pediatricians will forget the heroic efforts to care for the scores of children that needed us during that time.

Pfizer’s RSV vaccine RSVpreF was just given a positive review toward FDA authorization for use in elderly by May. The products that are designed to protect infants should follow suit, with the pending RSV season and the strained pediatric capacity across the nation in mind.

Pediatricians often have to be the voice for children. So we are asking on their behalf now: Make the life-saving RSV vaccines for newborns available without delay and before they fill up pediatric emergency rooms and hospitals across the country, literally holding their breath waiting to see if the care they need will come in time.

Sallie Permar is pediatrician-in-chief at NewYork-Presbyterian Komansky Children’s Hospital and department chair of pediatrics at Weill Cornell Medicine. Karen Acker is hospital epidemiologist at NewYork-Presbyterian Komansky Children’s Hospital and assistant professor of clinical pediatrics at Weill Cornell Medicine.