AstraZeneca is buying its first vaccine company in a $1.1 billion deal that will expand the vaccine and immune therapy business it set up during the COVID pandemic.

The Guardian reported that the U.K.’s biggest pharmaceutical firm has agreed to take over the Seattle-based company Icosavax, which is developing a potential vaccine for two common respiratory diseases – respiratory syncytial virus (RSV) and human metapneumovirus (hMPV) – that cause severe illness and hospitalization. 

It is a combination protein VLP (virus-like particles) vaccine, which AstraZeneca says may offer benefits over other vaccines. U.K. rival GSK and U.S. firm Pfizer launched RSV vaccines this year. The GSK shot, called Arexvy, which was approved in the U.S. in May and in the U.K. in July, is expected to bring in more than £1bn in revenues in its first year on the market, making it a “blockbuster drug.”

The Massachusetts-based Moderna is awaiting regulatory approval in the U.S. and EU for its RSV vaccine, which is based on the mRNA technology that it used for its COVID jab. It is also testing a combination and hopes to have a triple vaccine against flu, COVID and RSV ready for 2026.