Global Courant
Respiratory syncytial virus – viral vaccine under investigation
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PfizerThe vaccine that protects adults age 60 and older against respiratory syncytial virus was slightly less effective after 18 months, according to clinical trial results the company announced Wednesday.
The data comes from New York-based Pfizer’s clinical trial in more than 34,000 older adults over two RSV seasons, or 24 months. The latest data specifically pertains to Northern Hemisphere contestants in “midway through season two”. the lawsuitthat is about 18 months after vaccination.
The injection was 78.6% effective at 18 months against more severe lower respiratory tract disease with three or more symptoms, slightly less than 85.7% on a year. Those symptoms include wheezing, shortness of breath, rapid and shallow breathing, and mucus production.
According to Pfizer, after 18 months, the vaccine was about 49% effective against the same condition with two or more symptoms. That is a sharper decrease from the 66.7% efficacy of the injection after one year.
The vaccine was generally well tolerated, with no side effects reported by the participants at 18 months.
Pfizer presented the results an advisory committee from the Centers for Disease Control and Prevention on Wednesday. The committee will make a recommendation on when and how often to administer the company’s RSV shot in the US now that the Food and Drug Administration has approved the jab.
Pfizer’s RSV vaccine is the second to receive approval following an injection of GlaxoSmithKlinewhich will present similar long-term data on Wednesday.
Pfizer’s results are a first glimpse of the vaccine’s durability against RSV, which causes mild symptoms similar to the common cold in most people, but more severe infections in older adults and children.
The data suggests that the protection afforded by the vaccine is slowly declining over time, similar to what is seen with vaccines for Covid and the flu.
But the 18-month data also suggests that Pfizer’s injection is generally still protective against RSV after a year.
It is still unclear what the effectiveness of the vaccine looks like after 24 months. Pfizer expects to release that data later this year, which will provide a better picture of the shot’s durability.
Annaliesa Anderson, head of Pfizer’s vaccine research and development, told CNBC the company is “very encouraged” by data from the phase three clinical trial.
She noted that the vaccine maintained high efficacy against lower respiratory illnesses with three or more symptoms, which is more severe than the same illness with two or more symptoms.
“As with most vaccines, you’re really looking for an effect against a more serious disease that causes higher levels of mortality, morbidity and health care contact,” Anderson told CNBC. “It’s very important for us to see high efficacy, and we think it will bring comfort to people as they take the vaccine.”
Pfizer has not released data on the effectiveness of its vaccine against severe RSV illness, defined as a patient requiring hospitalization, oxygen support or a mechanical ventilator.
Anderson said studies are ongoing, as well as research evaluating the effectiveness of the shot in older adults with weak immune systems.
RSV kills 6,000 to 10,000 older adults each year and hospitalizes 60,000 to 160,000 of them, according to the CDC.
The risk of hospitalization increases with age, and adults age 70 and older are more vulnerable.
Pfizer estimates that if 50% of people age 60 and older receive its shot for older adults, the vaccine could prevent more than 5,000 deaths, 68,000 hospitalizations, 51,000 emergency room visits, and more than 422,000 outpatient visits.
