H5N1 avian influenza continues to spread amid commercial and backyard poultry, and additional cases have been reported in domestic cats

An avian flu outbreak in NSW has been eradicated, health authorities say, as the state joins Victoria in lifting restrictions on poultry and egg producers.

"The Chinese poultry lineage may have experienced more vaccine-driven selection compared to other lineages," the researchers wrote.

H5N1 vaccines have been previously licensed, and millions are in the national stockpile. But even with the news of the country’s first human death due to bird flu, vaccination isn’t yet recommended.