THE US government has declared that H7N9 bird flu “poses a significant potential for a public health emergency”, and has given “emergency use authorisation” for diagnostic kits for the virus. This means tests can be used that haven’t gone through the usual lengthy approval process by the US Food and Drug Administration.
They are right to be concerned. H7N9 could be a tough adversary: New Scientist has learned that it provokes a weaker immune response than most flu, making vaccines hard to produce.