A universal vaccine has come a step closer after researchers carried out successful trials on mice.

The spray would target all types of normal influenza and would not require expensive annual reformulation and re-vaccinations as existing treatments do, according to the scientists.

The test vaccine provided mice with 100 per cent protection against a laboratory strain of virus and 20 per cent protection against bird flu.

These results offered the same protection achieved with commercially available anti-influenza drugs.

When specific peptides were inhaled through the mice’s noses, they triggered an immune  response to part of the virus which is present in all strains, the team found.

Reformulating vaccines every year was ‘time consuming, labour intensive and expensive’, said lead researcher Dr Darren Miller at the University of Adelaide.

‘A totally synthetic universal vaccine – one not derived from an influenza virus – would have clear advantages to control and prevent the spread of flu,’ he added.