US CDC advisers weigh use of GSK, Pfizer RSV vaccines in older adults

The expert panel is expected to discuss exactly who should receive the vaccines as well as how frequently. Pfizer is expected to present data on the efficacy of its vaccine over a second year at the meeting, while GSK said that a single dose of its RSV shot was 67.2% effective in preventing lower respiratory tract disease over two RSV seasons in older adults.

A panel of advisers to the U.S. Centers for Disease Control and Prevention (CDC) on Wednesday will vote on whether to recommend the use of recently approved vaccines from Pfizer and GSK to prevent severe respiratory syncytial virus (RSV) infections in older adults.

If the CDC's Advisory Committee on Immunization Practices backs the vaccines and the agency's director formally signs off on their use as expected, the shots can be rolled out ahead of the RSV season this fall. The expert panel is expected to discuss exactly who should receive the vaccines as well as how frequently.

Pfizer is expected to present data on the efficacy of its vaccine over a second year at the meeting, while GSK said that a single dose of its RSV shot was 67.2% effective in preventing lower respiratory tract disease over two RSV seasons in older adults. The GSK shot was 78.8% effective against severe disease over that time period, the company said.

The U.S. Food and Drug Administration last month approved the first RSV shot from GSK, branded as Arexvy, and later Pfizer's Abrysvo for people aged 60 and older to protect them from lower respiratory tract disease caused by the virus. Scientists have long sought a vaccine for RSV, which usually causes mild, cold-like symptoms but can also lead to serious illness and hospitalization. It is estimated to be responsible for 14,000 deaths in adults aged 65 and older in the United States annually, according to government data.

Pfizer and GSK have said they expect RSV vaccines to eventually become multibillion-dollar sellers. GSK has said it expects the U.S. market to be in the range of 10 million to 15 million people this year, a fraction of the size of the expected flu or COVID-19 market for 2023.

In its late-stage study, Pfizer's vaccine was nearly 67% effective among participants aged 60 and above with two or more symptoms, and 85.7% effective in preventing severe disease defined by three or more symptoms. GSK's vaccine showed overall efficacy of 82.6% and was about 94% effective against severe lower respiratory tract disease associated with an RSV infection.