Pfizer’s (NYSE:PFE) vaccine against respiratory syncytial virus maintained protection for older adults across two full seasons of the disease in an ongoing late-stage clinical trial, the company announced Thursday.
The shot’s efficacy declined slightly compared with the levels of protection after one RSV season, but the new data suggests that the jab generally offers durable protection for adults ages 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 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.
A single dose of 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. Those symptoms include wheezing, shortness of breath, rapid and shallow breathing, and mucus production.
The shot was roughly 55.7% effective against a less severe form of that condition with two or more symptoms after the end of season two, according to the initial data on more than 37,000 participants in the Northern and Southern Hemispheres. The jab showed 66.7% efficacy against that condition after one RSV season.
PFE shares eked up seven cents to $27.11.
