The panelists seemed significantly more confident about the demographic profile used during the GSK study in comparison to Pfizer's (PFE.N) RSV vaccine, which was recommended by the FDA panel on Tuesday.
Pfizer and GSK are running a tight race to tap into the RSV vaccine market, which is estimated to be over $5 billion and could exceed $10 billion by 2030, according to analysts.
There is currently no approved vaccine to prevent lower respiratory tract disease caused by RSV in older adults, which causes death of 14,000 adults aged 65 and older annually in the United States.
In October, late-stage data of GSK's RSV vaccine showed it to be 82.6% effective in preventing lower respiratory tract disease in people aged 60 and over, while Pfizer's vaccine was 66.7% effective.
If approved, we estimate peak sales for GSK vaccine to be about $2.8 billion globally, said Evan Wang, Guggenheim Securities analyst, ahead of the panel vote.