Parents are being warned to look out for signs of whooping cough in their children as an outbreak sweeps through Canterbury, Nelson and Marlborough.
Three babies have been hospitalised in Canterbury and 18 cases were reported in the Nelson-Marlborough region in February.
A spokesperson for Nelson GPs, Graham Loveridge, says many children have not been immunised because the disease has not had a high profile in recent years.
Dr Loveridge says whooping cough can be very severe and occasionally a child dies from it.
"Younger kids get very badly affected and some get hospitalised. A kid with a whooping cough affects the whole household and the best chance you can give your kid is to have the immunised - and the younger, the better."
He says says it is concerning that many cases of whooping cough are probably not being reported or treated.
