An infectious disease expert says the relatively mild cases of avian influenza detected so far among dairy workers don’t warrant making a vaccine available to them, even as they work to contain and prevent spread of the contagious virus among herds.

"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.