There are four new Covid-19 cases today in managed isolation.

• One case is an international mariner staying at the Sudima Christchurch Airport, detected at day 15 testing as a close contact of a day 6 case. The person is now in quarantine.

• One case arrived on 19 October from Milan via Singapore and tested positive to routine testing at around day 12. The person is now in the Auckland quarantine facility.

• One case arrived on 28 October from London via Singapore and tested positive to routine testing at around day 3. The person is now in the Auckland quarantine facility.

• One case was detected in managed isolation in Auckland, after being given permission to join a family member recently arrived from overseas. The family member has previously been recorded in our positive case totals. Today's case will be recorded as an import-related case.

Director-general of health Dr Ashley Bloomfield. Photo / NZ Herald

There were two new cases of Covid-19 in New Zealand yesterday, both in managed isolation.

Yesterday marked 10 days since there had been a community case and the Christchurch rubbish bin cluster also closed.

The latest cases were detected during routine isolation and testing processes and were now at the Auckland quarantine facility, the Ministry of Health said.

They were a person who arrived from Amsterdam via Singapore on October 23 and another who arrived from the UK via Dubai and Malaysia on October 19.

New Zealand's total number of active cases is 77 - there have been 1603 cases overall.

The ministry also announced yesterday the Christchurch returnee cluster had been closed.

"It has been more than 28 days since the last case – the length of two infection cycles – and the cluster is now officially closed," the ministry said.

This cluster began with the report on September 19 of a person who developed symptoms and was tested after finishing 14 days in managed isolation and returning two negative tests on days 3 and 12.

Elsewhere, British Prime Minister Boris Johnson announced yesterday morning England would be returning to a national lockdown until December 1.

Vitamin C can help severe Covid-19 cases, NZ-led review finds

Vitamin C can help treat patients with severe cases of Covid-19, a Kiwi-led review has found.

But the Otago University researcher behind the study, just published in scientific journal Nutrients, stresses larger studies are needed to give more certainty - and that vitamin C shouldn't be seen as something that can prevent or cure coronavirus.

Here in New Zealand, sales of oranges, kiwifruit and supplements have surged - something the citrus industry has put down to Kiwis trying to stay healthy amid the Covid-19 crisis.