Photo: 123rf.com / Composite Image - RNZ
A long-awaited survey of Covid-19 infections has been delayed until next year.
In a statement, the deputy director of health Andrew Old admitted to RNZ the work "has taken longer than expected".
The ministry had originally planned to launch two surveys after the March peak of cases. An infection survey would randomly sample people to assess the prevalence of Covid-19 in the community.
The second survey, a seroprevalence survey, would assess the number of people with antibodies to Covid-19 from infection, vaccination, or a combination of both.
Former director-general of public health Ashley Bloomfield said in July he expected the surveys to start shortly.
At the time, he said the infection survey would be run over a six-month period and test 1000 people a week. The second survey would be a blood test.
"Both are well developed and nearly ready to start rolling out in the next few weeks."
But Old today told RNZ the survey is now delayed again from the final quarter of this year until 2023. A second phase is not expected to start until July, a full year after it was initially expected to launch.
Old said the survey had taken longer to implement because of the "Covid-19 and winter illness surge on our health sector, as well as the resetting of roles and responsibilities, governance, priorities and budgets prompted by the health sector reforms."
This had a greater impact on the survey than expected, he said.
New Zealand relies on people reporting infections, and on wastewater testing to assess the spread of Covid-19 in communities. Recent wastewater results have suggested only 35 percent of cases are reported.
The United Kingdom has had a prevalence survey in place since 2020.
Old said the surveys are helpful studies, "but not critical to our response".
Part of the delay was caused by an additional stage to the survey being added. "This additional stage has a strong Maori and Pasifika component, which has been shaped in consultation with our sector partners, and will further enhance understanding of the impact of Covid-19 on specific communities and inform the ongoing public health response."
In August, University of Auckland Covid-19 modeller Dr Dion O'Neale said prevalence surveys were one of the best ways to get an estimate of the true number of infections in a community.