(Reuters) - 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.

RSV vaccines have reportedly fallen since U.S. regulators narrowed the targeted age range for the shots and indicated they may only be needed once in a lifetime. According to Reuters, some pharmacists are reporting a drop in demand of as much as two-thirds this year over last year,

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,

The UK High Court has ruled that two GSK respiratory syncytial virus (RSV) vaccine patents are invalid in an action involving Pfizer, as both companies battle to become the first to launch an RSV vaccine on the UK market.

On Monday, Pfizer Inc. (NYSE:PFE) stock is trading higher with a session volume of 31.16 million as per data from Benzinga Pro. Activist investor Starboard Value has invested approximately $1 billion in Pfizer as the pharmaceutical giant grapples with a downturn in demand for COVID-19 vaccines and treatments.

Pfizer and its German partner BioNTech on Tuesday won their attempt to invalidate two of rival CureVac's patents at London's High Court.

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.