Public health officials are urgently trying to sequence a strain of whooping cough to see if it's unusually deadly.
The rush for clarification comes in the wake of what's now three deaths of babies from whooping cough.
Those three deaths come out of just eleven known cases.
On the other hand, it could be that it's far more widespread than those numbers suggest.
Te Whatu Ora's public health director Dr Nick Chamberlain spoke to Guyon Espiner.
