This season’s uptake of RSV vaccines in the US has been slower than expected, according to Wall Street analysts tracking prescriptions, and appears to be missing even modest projections for growth compared with 2023.
The RSV, or respiratory syncytial virus, space is dominated by GSK’s first-to-market vaccine Arexvy, which has around 60% retail market share, according to Jefferies analysts, who put out an analysis of the market on Friday. Almost all of the rest has gone to Pfizer’s Abrysvo, with Moderna’s mRESVIA taking only a small slice, they said.
Last year at this time, 1.5 million prescriptions had been issued for the vaccines. But this year, only 900,000 have, according to Jefferies. That represents a 40% drop compared to last year. The RSV vaccination season runs from August to October.
GSK has been hit especially hard — weekly Arexvy prescriptions are down more than half versus last year, Barclays analysts said in a separate note issued Tuesday. The product is a major part of GSK’s strategy targeting infectious diseases, and last year sales reached about £1.2 billion ($1.6 billion) in 2023 in what the company described as an “exceptional launch” after FDA approval in early May.
There are some signs of growth. In the final week of September, Arexvy prescriptions were up 11% week-over-week, according to Jefferies, and prescriptions of Pfizer’s Abrysvo are growing 15% week-over-week. Abrysvo was cleared by the FDA in late May last year, and is the only one of the three vaccines recommended for use in pregnant women.
In July when the company shared quarterly results, CEO Emma Walmsley said that “with a best-in-class data profile, we are confident Arexvy will return to growth next year and longer term can achieve more than £3 billion in peak year sales.” A GSK spokesperson told Endpoints News that the company’s projections have not changed.
The Barclays analysts said they have reduced their Arexvy forecasts for the year “given the uncertainty around revaccination” frequency, adding that higher rates of Covid-19 vaccinations are also likely to “have a dampening effect on RSV.” GSK recently released details of a clinical study of the shot which is assessing the efficacy of dosing every three to four years.
In June, the CDC’s Advisory Committee on Immunization Practices declined to make a recommendation for Arexvy for people aged 50 to 59 years — a key age group for which GSK had been hoping to expand coverage. The following month, Walmsley described the committee’s delay as “surprising,” but said the drugmaker remains “confident” that Arexvy’s benefit to these patients will be recognized.
Meanwhile, Moderna’s mRESVIA prescriptions are growing every week but remain “incremental,” Jefferies analysts said.
“We are waiting for an inflection point as [the company] works on securing contracting which likely won’t have an impact until the following season,” they said in their report to investors. Moderna’s shot secured approval in May, roughly a year after the two other vaccines.