An Australian start-up developing a vaccine against one of the world’s most prolific bacterial pathogens – one which is responsible for causing a wide range of illnesses from middle ear infections to life-threatening pneumonia – has scored a $300 million valuation as part of its latest funding round.

GPN Vaccines has raised $US12 million ($18 million) in a round led by New York-based Forepont Capital, San Francisco’s Kern Capital and the founding partner of local fund Shearwater Capital, Mike Gregg.