There’s an uptick of Covid-19 in the Wellington region, specifically the Hutt Valley, but many cases are going unreported.

Local wastewater testing data from the Institute of Environmental Science and Research (ESR), New Zealand’s Crown research institute, shows the amount of viral material detected is similar to early April.

Back then, an average of 198 cases were reported a day, but as of September 24, just 52 cases a day were reported.

It comes as Prime Minister Chris Hipkins, who is also the MP for Remutaka, has tested positive for the virus.

He tested positive after experiencing “cold and flu symptoms” from Saturday.

Hipkins will be isolating for five days or until he returns a negative test, his spokesperson said.

ESR wastewater testing and reported Covid-19 cases in the Wellington region over the past six months.

ESR wastewater testing and reported Covid-19 cases nationally over the past six months.

ESR senior scientist Joane Hewitt said there has been no real change in test results from Moa Point or Porirua and the increase in viral material detected was coming from the Hutt Valley.

Hewitt stressed these results did not equate to a spike in Covid-19 when compared to peaks during the whole lifetime of the virus.

She said the number of reported cases has declined since Government isolation rules changed.

“There’s an expected decrease in reported cases and the wastewater will better reflect the amount of infections going around the community.”

The Government dropped the last of its Covid restrictions in August, meaning the last masking mandate and isolation requirements were lifted.

There is instead a recommendation to isolate for five days if someone has tested positive.

“While not mandated, the Ministry of Health guidance is to stay at home for five days if you’re unwell or have tested positive,” Health Minister Dr Ayesha Verrall said at the time.

This followed public health advice that the risk from Covid-19 was low and it was now safe to remove the final requirements, she said.

“While our case numbers will continue to fluctuate, we have not seen the dramatic peaks that characterised Covid-19 rates last year.”

ESR wastewater testing and reported Covid-19 cases in Wellington for all time.

Epidemiologist Michael Baker said there was less incentive for people to self-report after mandatory isolation was dropped, along with the associated financial compensation.

He said hospitalisations and wastewater testing provided reliable data.

Baker could not think of any obvious reason why Covid-19 has become more prominent in the Hutt Valley recently.

But he said it was information for action.

“If we see a significant tick-up like that, we should be more vigilant about managing the infections.”

This could include people working from home more, where possible, and wearing masks on public transport, he said.

Te Whatu Ora Capital and Coast has been approached for comment.

Georgina Campbell is a Wellington-based reporter who has a particular interest in local government, transport, and seismic issues. She joined the Herald in 2019 after working as a broadcast journalist.