A single nasal spray vaccine could protect against all coughs, colds and flus, as well as bacterial lung infections, and may even ease allergies, say US researchers. The team at Stanford University have tested their "universal vaccine" in animals and still need to do human clinical trials. Their approach marks a "radical departure" from the way vaccines have been designed for more than 200 years, they say. Experts in the field said the study was "really exciting" despite being at an early stage