The Centre for Health Protection has found the same mutation in three human swine influenza virus samples as the one detected in Norway recently, bringing the total number of them in Hong Kong to eight.

Among these cases, three of the patients died and one is still receiving intensive care treatment. The other four recovered. These viruses are still sensitive to antiviral drugs, oseltamivir and zanamivir.

Scientists in the World Health Organisation network of influenza laboratories are assessing the mutation's significance.