COVID-19 wastewater levels rise three weeks in a row

Rowan Quinn for RNZ

There has been a small sting in the tail of the COVID-19 Christmas wave, with an apparent rise in cases this month.

The wave had been declining, but latest ESR data showed the level of the virus in wastewater has risen for three weeks in a row.

COVID-19 modeller Michael Plank said even though wastewater readings could bounce around a little, it appeared there had been a rise in actual cases, with those reported to Te Whatu Ora also trending upwards.

That was probably because more people had been returning to work and school after the holidays, he said.

But the current wave was still generally tracking down.

"It's quite possible we'll see some little peaks and troughs on the downward slope and we've seen this before - as schools go back you get a bit of a bump in numbers for two or three weeks or a maybe a little longer, but then it is relatively short lived and then it starts to come down again," he said.

The number of people currently hospitalised with the virus was 200 - about half the number at the peak in December.

"That peak was itself already much smaller than many of our previous waves," he said.

The Christmas wave was mainly driven by the JN1 variant, which now made up about 93 percent of all cases.