American pharmaceutical giant Pfizer and German biotech firm BioNTech will pay Britain's GSK and Germany's CureVac US$740 million plus royalties to settle US legal disputes over Covid-19 vaccines, CureVac said on Friday.

The royalties would amount to a "single-digit" percentage on sales of Covid-19 vaccines in the United States, CureVac said.

The German firm added that it would grant Pfizer and BioNTech the non-exclusive licence to make and sell mRNA-based Covid and flu products in the United States.

GSK, which has worked with CureVac since 2020 to develop mRNA vaccines for infectious diseases, said that it would receive US$370 million as well as a 1 percent royalty on US sales of flu, Covid and "related combination mRNA vaccine products".

CureVac sued German rival BioNTech in 2022, arguing that it had infringed patents relating to mRNA technology in making its blockbuster Comirnaty coronavirus vaccine in collaboration with Pfizer.

Unlike traditional vaccines that contain some form of the dead or inactivated target virus, mRNA vaccines contain genetic materials that instruct human cells to make proteins typical of the targeted virus.

Since the virus need not be grown in the lab, mRNA vaccines can in theory be developed at scale more quickly than conventional vaccines.

The Pfizer-BioNTech vaccine was the first mRNA vaccine approved for use and the first Covid vaccine to receive approval in the West.

CureVac's own efforts to make an mRNA-based Covid vaccine during the pandemic did not come to fruition.

The deal brings the dispute between CureVac and BionNTech to an end ahead of the planned acquisition of CureVac by BioNTech, announced in June.

CureVac and BioNTech are still locked in legal disputes in Germany but CureVac said the deal "set a framework for resolving ongoing patent disputes outside the US".

In March, a German court sided with American pharmaceutical firm Moderna in its claim that BioNTech and Pfizer had broken one of its patents in making its Covid-19 vaccine. (AFP)