Six historical Covid-19 cases all linked to Waikato have been confirmed in New Zealand today, meaning the country's first confirmed Covid-19 coronavirus case dated back earlier than previously reported.
The historical cases include one confirmed case and five probable cases, none of which present a risk to the public, the Ministry of Health said this afternoon.
The infection occurred in late February following exposure to an infected person - a family member - visiting the country from Italy.
During their stay, the family member became ill with symptoms consistent with Covid-19, after which the wider household also became ill.
The confirmed case began showing symptoms of Covid-19 upon their arrival in the country on February 21, one week before the first confirmed case - a person in their 60s who had recently returned from Iran - was reported on February 28.
The other household cases would represent the first locally acquired cases of Covid-19 in New Zealand, given the onset of symptoms from February 29 for the confirmed case.
The household had not been tested as they did not meet the case definition for testing at the time, which was people with defined symptoms who had travelled from or transited through China. Italy had not at that point been identified as a country of concern.
Today’s historical confirmed case - a man - sought testing after he had recently developed a sore throat. The weak positive result, combined with serology test results and case history, is consistent with an old infection, the Health Ministry said.
Only today's case will be counted as a confirmed case at this stage after returning a weak positive result on the PCR test. The other family members will be recorded as probable cases.
Further investigation on the historical cases will continue.
Close contacts of the man during his recent mild illness have been tested as a precaution and have returned negative tests.
It's known some people can return a positive PCR test long after they have recovered from the illness and are no longer infectious.