University of Michigan and Centers for Disease Control and Prevention (CDC) investigators determined that both maternal respiratory syncytial virus (RSV) vaccination and the monoclonal antibody nirsevimab are likely cost effective in certain situations for RSV.
These findings, both published today in Pediatrics, were presented to the CDC's Advisory Committee on Immunization Practices (ACIP) and were instrumental in the recommendation of these products.
Both studies assessed the cost-effectiveness of these products for infants in their first RSV season; the maternal vaccine is administered during weeks 32 to 36 of pregnancy, with maternal antibodies passed through the placenta.
The monoclonal antibody is given as a one-time injection to infants under 8 months before their first RSV season if they did not benefit from maternal vaccination. Older babies at risk for severe RSV can also get nirsevimab during their second RSV season.
Fewer nirsevimab doses needed to protect
For the first study, which looked at the cost-effectiveness of maternal vaccination, the authors assumed a seasonal strategy with vaccination administered from September to January, aligning with the peak RSV season.
With an assumed cost of $295 per dose of vaccine plus administration costs, the incremental cost-effectiveness ratio (ICER) is calculated at $163,513 per quality-adjusted life year (QALY) saved. That compares with $396,280 per QALY for year-round vaccination.
The model projected that vaccinating about half of all US pregnant women in the US birth cohort would prevent 45,693 outpatient visits, 15,866 emergency department (ED) visits, and 7,571 hospitalizations related to RSV in infants annually.
For nirsevimab, the antibody proved highly effective in preventing RSV-related hospitalizations and other severe outcomes, resulting in an ICER of $153,517 per QALY saved, assuming a cost of $495 in the private sector and $395 through the Vaccines for Children program.
In order to prevent 1 infant hospitalization, the authors found that 234 pregnant women would need to be vaccinated. The number needed to administer for nirsevimab to prevent 1 RSV hospitalization was 128.
The researchers estimated that 107,253 outpatient visits, 38,204 ED visits, and 14,341 hospitalizations could be averted each year if half of eligible US babies receive nirsevimab.
Both vaccine, antibody injection expensive
Though both interventions prove cost-saving, the high market prices for the products, especially nirsevimab, mean the interventions come with significant societal costs. The cost of a single dose of maternal vaccine is $295, whereas the market cost of nirsevimab is $495. To compare, the annual flu vaccine ranges from $19 to $32 per dose.
In a commentary on the studies by Sean O'Leary, MD, MPH, University of Colorado School of Medicine, O'Leary said that, in the analysis for nirsevimab, if the cost per dose were $50, the drug would be cost saving.
It is conceivable that market forces will bring down the remarkably high costs of these products.
"Although it is unlikely we will see the costs drop to that extent in the coming years," he wrote, "with several other RSV-prevention products in the pipeline, it is conceivable that market forces will bring down the remarkably high costs of these products."
