A whooping cough epidemic that killed a Christchurch newborn last year is still putting a strain on the nation's health system.
Canterbury recorded 1209 notifications of whooping cough, also known as pertussis, in 2012 - the highest for any health board area.
There were 5938 notifications across the country last year, compared to 1996 in 2011.
Last year's notifications included 2555 confirmed cases, 2944 probable cases, 292 suspected cases and 147 still under investigation.
About 7.1 per cent (427) of the 2012 cases were in infants aged under one year and 309 people were taken to hospital.
Two children died from the disease last year, including 6-week-old Christchurch girl Alaya-Reign Pamata Ma'anaima.
The baby died in Christchurch Hospital on November 10 after being diagnosed with the disease nine days earlier.
Canterbury medical officer of health Alistair Humphrey said the whooping cough epidemic, which began spreading across the country in May 2011, was "not abating", with another 96 cases reported in Canterbury in January.
Free vaccinations were available to women between 28 and 38 weeks of pregnancy from their GP until the pertussis outbreak ended.
"It's very distressing for parents when they see their children going through this," Humphrey said.
Whooping cough causes uncontrollable coughing and is commonly known as the 100-day cough.
It is highly infectious, but can be treated with antibiotics.
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