On April 1, 2025, the European Commission (EC) approved Pfizer's respiratory syncytial virus (RSV) vaccine, Abrysvo, for use in individuals aged 18 to 59 years. This significant expansion makes Abrysvo the first and only RSV vaccine authorized in the European Union (EU) for non-pregnant adults within this age group, marking a crucial advancement in public health.
RSV is a highly contagious virus that typically causes mild, cold-like symptoms in most people. However, it can lead to severe illness among vulnerable populations, including older adults, infants, and individuals with chronic medical conditions. According to Pfizer, RSV results in approximately 158,000 adult hospital admissions each year due to the complications it can cause.
The recent approval from the EC follows a favorable recommendation from the European Medicines Agency (EMA) and is supported by positive results from the late-stage MONeT trial. This trial evaluated the effectiveness of Abrysvo in adults aged 18 to 59 who are at risk of RSV-associated lower respiratory tract disease (LRTD) due to specific chronic medical conditions.
The MONeT trial achieved its co-primary immunogenicity endpoints and primary safety endpoint. Participants demonstrated neutralizing responses to RSV-A and RSV-B that were non-inferior to those observed in the phase 3 RENOIR study, which focused on older adults. Additionally, trial participants exhibited at least a four-fold increase in serum neutralizing titres for both RSV subtypes one month after vaccination.
Alexandre de Germay, Chief International Commercial Officer and Executive Vice President at Pfizer, expressed enthusiasm about the approval, stating, "We are thrilled that Abrysvo is now approved in the EU to help prevent RSV in adults aged 18 and older. This expanded authorization signifies another step for public health by offering the potential to substantially reduce the burden of RSV in future seasons." He emphasized the importance of the vaccine for pregnant individuals as well, noting that it provides passive protection to infants from birth up to six months of age when administered during pregnancy.
The expanded indication for Abrysvo aligns with regulatory progress in the United States, where the U.S. Food and Drug Administration (FDA) had previously approved the vaccine for adults aged 18 to 59 at increased risk for RSV-related LRTD in October 2024. The FDA had initially granted approval for the vaccine in May 2023 for individuals aged 60 and older.
This regulatory approval comes at a time when both Pfizer and GSK, which produces a competing RSV vaccine named Arexvy, are vying for market share in the RSV vaccine sector. While GSK has secured approval for older adults, it has yet to gain authorization for the younger high-risk population, potentially giving Pfizer a competitive edge.
Despite the promising developments, recent sales figures indicate a decline for both companies. Pfizer reported a staggering 62% year-over-year drop in Abrysvo sales during the fourth quarter of 2024, attributing this decrease to lowered vaccination rates following changes in U.S. guidelines. GSK experienced an even steeper decline, with a 69% drop in sales for Arexvy.
In the UK, early data suggests that Pfizer's vaccine is making a positive impact. The UK Health Security Agency (UKHSA) reported a 30% reduction in hospital admissions among individuals aged 75 to 79 since the launch of the RSV vaccination program in September 2024. This program covers both older adults and pregnant women, and its impact is expected to grow as vaccine uptake increases.
In 2024, Pfizer secured a significant contract to supply around five million doses of its RSV vaccine for older adults and pregnant mothers in England and Northern Ireland over the next two years. This deal positions Pfizer favorably in the competitive landscape, even as long-term projections still favor GSK, with estimates suggesting that Arexvy could generate $2.4 billion in revenue by 2030, compared to $1.5 billion for Abrysvo.
Abrysvo is contraindicated for individuals with severe allergic reactions to any vaccine component. Clinical trials have indicated a potential increased risk of Guillain-Barré syndrome and fainting following vaccination. Additionally, individuals with weakened immune systems may experience a reduced immune response. Common side effects reported for adults aged 18 to 59 include pain at the injection site, muscle pain, joint pain, and nausea. For pregnant individuals, the most frequently reported adverse events include injection site pain, headache, muscle pain, and nausea, with some cases of low birth weight and jaundice observed in infants born to vaccinated mothers.
As the RSV vaccination landscape evolves, the expanded approval of Abrysvo represents a significant step forward in efforts to combat this common but potentially severe virus. The continued collaboration between regulatory bodies and pharmaceutical companies is crucial in addressing public health challenges posed by respiratory viruses.
