Whooping cough cases down but epidemic ongoing – Michael Baker

“Not only is our coverage continuing to fall, the inequalities and inequities are very large.”

Whooping cough cases have decreased, with 91 across the motu for the week ending 17 January, according to ESR data.

However, University of Otago professor in public health Michael Baker says the epidemic – declared by Health New Zealand Te Whatu Ora in a media release in November 2024 – will likely take the country through to 2026.

“[Outbreaks of whooping cough] can be quite prolonged,” Professor Baker says.

The current epidemic could also last longer, he says, due to the lowest vaccination coverage Aotearoa has seen in 15 years.

“For children under the age of two, [whooping cough vaccination] is now down to 75 per cent overall.

“Not only is our coverage continuing to fall, the inequalities and inequities are very large.”

Professor Baker says antenatal vaccination is still the “number one measure” to combat the spread of whooping cough, also known as pertussis.

Cases of the disease hit the highest in this epidemic so far towards the end of last year, with ESR reporting 168 cases in the week ending 6 December.

The first three weeks of 2025 have seen fluctuating case numbers, beginning with 73 at the end of the first, to 109 in the second and 91 in the third.

Of those 91 cases, Canterbury had the most at 23. Capital, Coast and Hutt Valley, and the Southern region, each reported 10 cases.

Last year ended with 1768 reported cases of whooping cough in total. This year has seen 273 so far.

Of these cases:

• 22 have been hospitalised, with 0 to five months and 15 to 64-year-olds most affected.

• 179 were not hospitalised.

• 27 are unknown.

Since New Zealand Doctor Rata Aotearoa last reported on pertussis figures, the most affected age has shifted from 15 to 64-year-olds, to five to 14-year-olds. Fifty-three of the latest cases fall into this age group.

However, babies and infants are particularly at risk. Te Whatu Ora reported the death of a child from whooping cough over the Christmas period.

National Immunisation Taskforce chair Owen Sinclair (Te Rarawa) told New Zealand Doctor (online 17 January) this death, which occurred in a rural area, could be attributed to systemic failures in the health system.

The mother struggled to get immunised against pertussis during her pregnancy, which Dr Sinclair says demonstrates the acute accessibility issues for healthcare services in many rural areas.