Researchers accused of scaremongering over campylobacter hospitalisation, death rates

Otago Daily Times

6 days ago

Too many people are still ending up sick and in hospital from contaminated fresh chicken meat, public health professionals say.
New analysis released by the Public Health Communication Centre (PHCC) on Thursday shows hospitalisation rates for campylobacter infection have increased by almost 70% in 17 years. The study found contaminated fresh chicken meat remained the dominant source, causing an estimated 77% of infections.
But the Ministry for Primary Industries (MPI) has disputed the figures and is accusing the researchers of scaremongering.
The PHCC study noted that, in 2007, regulatory measures were introduced to reduce contamination levels in fresh chicken meat tested in processing plants. Rates of both hospitalisation and notification halved in just a few months as a result.
But since 2008, contaminated chicken in New Zealand caused more than 600,000 symptomatic illnesses, over 9000 hospitalisations, at least 60 deaths and around $1.4 billion in economic costs.
Lead author, University of Otago professor Michael Baker, said that in 2023, the year with the most recent data, there were nearly a thousand hospitalisations.
"By any means this is a very consequential health problem and we feel it needs a much more vigorous response."
Government agencies were "too complacent" about the increasing rates of campylobacter infection caused by contaminated chicken, he added.
"If you saw a 70% rise in our most common foodborne disease surely you'd be putting a lot of effort into investigating that to figure out what's going on, and I'm not aware of any effort going into that. One of the major problems that we're seeing is our agencies have become very complacent about this infection."
The government should consider a formal inquiry into this serious, long-term regulatory failure, Baker said.
"The large Havelock North waterborne outbreak of campylobacter infection [in 2016] resulted in an exhaustive inquiry and a complete reorganisation of the drinking water supply sector. That common source outbreak caused about 7570 cases. By comparison, the 'common source' epidemic caused by contaminated chicken meat results in the equivalent of a Havelock North-sized outbreak every three months in NZ, or 80 such outbreaks since 2008."
But Food Safety's deputy director-general Vincent Arbuckle disagreed with the PHCC's analysis, arguing that between 2006 and 2020 reported rates of foodborne campylobacter infections had halved. These figures were based on public notifications of infections provided by the health system, he said.
"In 2020 New Zealand Food Safety set the target of reducing the rate by a further 20%. This milestone was reached at the end of 2024, when rates of foodborne campylobacter infections acquired in New Zealand fell to 70 cases per 100,000.
The drop in infection was thanks to a "concerted effort over many years" from government, scientists and industry throughout the supply chain, he said.
"New Zealand has made considerable reductions in campylobacter infections. We keep an open mind about changes that can further reduce campylobacteria infection, which is a serious foodborne illness, but will not consider changes that are not founded on good evidence."
Arbuckle accepted more people were ending up in hospital with campylobacter but says that was partly because they had put off going to the GP and got sicker, he said.
He also agreed that campylobacteriosis was "the most common, significant foodborne illness in New Zealand".
But he said data suggested "a continued downward reduction due to the sustained efforts between industry, health authorities, the regulator and other parts of the sector such as retail".
"The prevalence [of campylobacteriosis] is reducing, it's not where people would like it to be, but some of the content in this report is simply erroneous and alarmist, particularly the comments about deaths attributed - the simple fact is that ... since 2007 we've had three recorded cases of death where campylobacteriosis was the principle single contributing factor, not 60 as he [Baker] suggests.
"If New Zealand was experiencing the level of deaths directly attributable to campylobacteriosis at the numbers that the authors suggest, there would be an outcry."
But Baker said that deaths from campylobacter infection were generally poorly diagnosed and recorded.
By looking at hospital discharge data, however, the researchers were able to get an indication of deaths in hospital with 60 reported deaths for patients with a discharge diagnosis of campylobacter infection as the principal or additional diagnosis over the 14-year period from 2008 to 2021, an average of 4.3 per year.
An additional estimated 12 deaths from Guillain-Barré syndrome (GBS) from this source took the total to 68 in the 17-year period, or four per year.
In a statement, Poultry Industry Association executive director Michael Brooks said he agreed the paper was "unnecessarily alarmist".
"The poultry industry works closely with NZ Food Safety and met their set targets to further reduce campylobacter by 20% by 2024," he said.
"We have also met the standards of the National Microbial Database. NZ Food Safety assesses that Michael Baker's paper has significant limitations and relies on several incorrect assumptions and unsupported estimates to reach its conclusions."
The study's co-author, University of Otago Professor Nick Wilson defended their research on Morning Report, saying hospitalisation data is the most reliable source to understand what's happening with this "epidemic".
"They're [MPI] focusing on the wrong data. You need to take a broad comprehensive picture that includes looking at the hospitalisations and deaths. Hospitalisations are far more reliable then the data sources that they're focusing on," he said.
"They're just not taking a proper health perspective. You'd expect that a watchdog that's meant to be protecting public health and protecting food safety, it [MPI] just doesn't have a health focus."
MPI looks like they are protecting their own reputation, Prof Wilson said.
"This is a health problem... You need health experts. It's out of their ballpark."