By Rowan Quinn of RNZ
Public health officials are urgently trying to sequence a strain of whooping cough to see if it is unusually deadly.
Te Whatu Ora has set up an expert taskforce to investigate after three babies died from the disease, also known as pertussis, this year.
Te Whatu Ora public health director Nick Chamberlain said it was unusual to have had three deaths when there had only been 11 cases officially reported.