Covid 19 Omicron outbreak: Could the Delta variant return?

Toi Te Ora Public Health is not aware of any confirmed Delta cases in the Lakes district in the past month. Photo / Andrew Warner

Omicron has "overwhelmed" Delta but other Covid variants may arrive once the borders open, a public health expert says.

It comes as Toi Te Ora Public Health said Covid-19 cases in the Lakes district have been "100 per cent Omicron" in the past month.

Meanwhile, the Ministry of Health today reported that one person died with Covid-19 in the Lakes District Health Board region. Nationally, the ministry reported 34 Covid-related deaths.

There were nine patients with Covid in Lakes District Health Board hospitals.

There were 479 new cases of Covid-19 in the region, which included both PCR and RAT tests. Nationally, there were 17,148 new cases.

University of Waikato professor of public health Ross Lawrenson. Photo / Supplied

University of Waikato professor of public health Ross Lawrenson said it was more likely a new variant would arrive rather than Delta coming back.

"We are worried as the borders open that there may be other variants that come in."

Currently, people were getting either the sub-type of BA.1 or BA.2 Omicron, he said.

"We're assuming that that's overwhelmed Delta.

"We may be wrong - there may be some cases out there of Delta that we just haven't identified.

"Generally, I don't think that's likely because the Delta cases tend to get sicker. And if they're sicker then they will be more likely in hospital and we are testing those in hospital.

"We're not seeing Delta and we're not expecting a resurgence of Delta."

Lawrenson said the most infectious variants became dominant "quite quickly" and the less infectious variants "die out" because they were not being transmitted in the same way.

"Hopefully if there are future variants, they will remain relatively mild or even milder which would be great."

He said the "large numbers" of people getting Omicron would get "some protection" against future variants.

Toi Te Ora Public Health medical officer of health Dr Phil Shoemack. Photo / NZME

Toi Te Ora Public Health medical officer of health Dr Phil Shoemack said it was not aware of any confirmed cases of the Delta strain of Covid-19 in the Lakes district in the past month.

"All whole-genome sequencing results in the Lakes district in the past month have confirmed the Omicron variant."

When asked about "Deltacron", Shoemack said it was a "recently identified new variant" of the Covid-19 virus.

"All viruses have the capacity to mutate and Covid-19 is no different in that regard."

He said the Ministry of Health was "constantly in touch" with the World Health Organisation to monitor any new viral strains and the potential threat they may pose.

"At this stage, 'Deltacron' is not thought to pose any additional concern."