U.S. sales of RSV vaccines from GSK and Pfizer are down significantly after regulators narrowed the targeted age group and said it was a once-in-a-lifetime shot for now, excluding millions of people who got one last year.

The vaccine demonstrated efficacy across different respiratory syncytial virus (RSV) subtypes in older adults between the ages of 70 and 79 years.

Pfizer (PFE) has reportedly succeeded in getting a U.K. court to invalidate two of GSK’s (GSK) patents for its RSV vaccine. Read more here.

Pfizer on Monday won a bid in a London court to invalidate two of GSK's patents relating to a respiratory syncytial virus (RSV) vaccine. The two pharmaceutical giants are among a number of companies in competition for a vaccine for RSV,

Cumulatively, data showed the shot to be 63% effective across the three-year period. However, efficacy appeared to wane and GSK said it expects revaccination will eventually be needed.