GSK, Pfizer ready to launch RSV vaccines for older adults in US

Neither company would say how many doses of their vaccines they intended to have ready for their respective launches.

The U.S. Food and Drug Administration (FDA) is expected to approve both vaccines for people aged 60 and above by May, while an FDA decision on the use of Pfizer's vaccine for pregnant women is due in August. The EU's decision, which could pave the way for the vaccines to be introduced in the UK as well, are due in the second half of the year.

Annaliesa Anderson, Pfizer head of vaccines research & development, told the same briefing that the company anticipates a population of about 4 million pregnant women annually in the United States who could eventually receive its RSV vaccine, though the market will take time to shape.

She later told Reuters that the so-called "tripledemic" that hit the northern hemisphere this winter may have at least temporarily raised awareness of RSV, which despite its dangers for the very old and very young is not well known by the public.

"In the U.S. (this winter), the pediatric hospitals were full of babies all with RSV..., it certainly hit the news and people were much more aware," she said.

Given how contagious the virus is, the best way to protect infants from contracting the virus and becoming severely ill is by vaccinating their mothers during pregnancy, Anderson said.

GSK last year voluntarily stopped its clinical trial of its own RSV vaccine on pregnant women and is currently only pursuing the use of its vaccine on older adults, a company spokesperson told Reuters on Thursday.