Pfizer’s RSV Vaccine Shows Durable Protection for Older Adults Across Two Seasons, Boosting Market Share
Pfizer has announced that its vaccine against respiratory syncytial virus (RSV) has maintained protection for older adults across two full seasons of the disease in an ongoing late-stage clinical trial. While the shot’s efficacy declined slightly compared to the levels of protection after one RSV season, the new data suggests that the vaccine generally offers durable protection for adults aged 60 and above, who are more vulnerable to severe illness from RSV.
The launch of Pfizer’s vaccine, known as Abrysvo, and another RSV shot from GlaxoSmithKline (GSK) last year proved to be a boon for both companies, with the jabs accounting for hundreds of millions in just half a year on the market. Pfizer’s vaccine was 77.8% effective against more severe lower respiratory tract illness with three or more symptoms through a second season, down from the 88.9% efficacy following the end of one season. These symptoms include wheezing, shortness of breath, rapid and shallow breathing, and mucus production.
The initial data on over 37,000 participants in the Northern and Southern Hemispheres showed that Pfizer’s vaccine was approximately 55.7% effective against a less severe form of the condition with two or more symptoms after the end of season two. The jab demonstrated 66.7% efficacy against that condition after one RSV season. Pfizer noted that the vaccine showed consistent efficacy against RSV A and RSV B, which are the two major subtypes of the virus, after the second RSV season. The shot was specifically 80% or more effective against each type in patients with the more severe form of lower respiratory tract illness.
Importantly, no new adverse events were reported by patients after the two seasons. These positive results come ahead of a meeting of an advisory panel to the Centers for Disease Control and Prevention (CDC) on Thursday, which will consider whether seniors should take RSV shots annually or every other year. Analysts do not expect the committee to make a final recommendation until June, a decision that may have significant implications for Moderna, which is hoping to launch its own RSV jab this year.
Jefferies analyst Michael Yee believes there is a 50% to 70% likelihood that the panel will recommend annual vaccination, which would put Moderna in a position to achieve “at least equivalent market share” to Pfizer and GSK. However, a biennial recommendation based on data on GSK’s shot across two seasons would “reduce competitive positioning” for Moderna, Yee noted.
In older adults, GSK’s shot showed a cumulative efficacy of 67.2% against lower respiratory tract illness over two RSV seasons, compared to 82.6% after one season of the virus. GSK’s vaccine generated around £1.2 billion ($1.5 billion) in sales last year, while Pfizer’s shot, which is also approved for expectant mothers who can pass on protection to their children, recorded about $890 million in revenue in 2023.
RSV is a serious respiratory illness that kills 6,000 to 10,000 older adults and hospitalizes 60,000 to 160,000 of them every year, according to the CDC. The development of effective vaccines against RSV is crucial in reducing the burden of the disease and protecting vulnerable populations.
In conclusion, Pfizer’s RSV vaccine has demonstrated durable protection for older adults across two seasons of the disease. The vaccine’s efficacy remains high, offering significant protection against severe lower respiratory tract illness caused by RSV. These positive results have boosted Pfizer’s market share and have implications for Moderna’s upcoming RSV vaccine. The advisory panel’s decision on whether to recommend annual or biennial vaccination will shape the competitive landscape in the RSV vaccine market. Overall, the development of effective vaccines against RSV is a crucial step in reducing the impact of this respiratory illness on older adults.
