A participant in the Novavax vaccine trial at Howard University in Washington. Photograph: Kenny Holston/The New York Times

US biotech company Novavax announced a 90.4 per cent efficacy rate for its Covid-19 vaccine, boosting hopes that a new vaccine could come on stream th(...)

 An image from March 2012 of former US president George HW Bush in his office in Houston, Texas. File photograph: Larry W Smith/EPA

Former US President George HW Bush has been moved to an intensive-care unit at a Houston hospital with pneumonia and was stable and resting comfortabl(...)