A health expert believes an Omicron case in Palmerston North could have laid dormant for the duration of the person's MIQ stay and five negative tests.
After the negative tests, the person was released from the MIQ facility in Christchurch on Sunday, January 16. They got another Covid-19 test after becoming symptomatic and on Wednesday, January 19 received a positive result.
The Health Ministry yesterday said the case - who has had two doses of the Pfizer Covid-19 vaccine - was considered to be infectious from January 17 and there were multiple exposure events.
The person is now isolating at home.
University of Canterbury Associate Professor of epidemiology Dr Arindam Basu said Omicron was a peculiar variant so there were a few ways the person could have caught it.
They could have become "reinfected" after an earlier infection, caught it from someone else in MIQ, or their body could have incubated the virus at low enough levels to evade detection, he said.
Health officials said no further positive Covid-19 cases were detected in Palmerston North today.
The MidCentral District Health Board, which covers the greater Manawatū area, said as of 9am today yesterday's case remained the region's sole one.
There were 297 tests processed in the region yesterday, and 216 on Wednesday.
Ninety-three per cent of people in the MidCentral region are fully vaccinated.
There are 14 locations of interest in Palmerston North.
People at Cafe 116 in Terrace End from 10.10am to 11.30am on January 19 are considered close contacts of the case and should isolate and test immediately. Those at other listed locations are asked to self-monitor for 10 days and get a test if symptoms develop.
The Ministry of Health today reported 23 new community Covid cases and 44 at the border.
Full list of locations:
• Cafe 116 Terrace End (116 Napier Rd, Terrace End) Wednesday January 19, 10.10am-11.30am (close contact).
• eSANZ Milson (73 Milson Line) Tuesday January 18, 2.15pm-2.30pm.
• Postie Palmerston North (Shop 1A 210-246 Rangitikei St) Wednesday January 19, 11.15am-11.45am.
• Bunnings Warehouse Palmerston North (Corner Tremaine Ave & Railway Rd) Monday January 17, 4.54pm-5.05pm; Tuesday January 18, 10.30am-10.48am.
• Amare Safety Palmerston North (661 Tremaine Ave) Monday January 17, 3pm-3.10pm; Wednesday January 19, 11.45am-11.50am.
• Repco Tremaine Ave Palmerston North (915 Tremaine Ave, Roslyn) Monday January 17, 3.55pm-4.35pm; Tuesday January 18, 10.20am-10.30am; Wednesday January 19, 1.55pm-2.05pm.
• Steelmasters Palmerston North (676 Tremaine Ave, Papaioea) Monday January 17, 3.10pm-3.28pm; Wednesday January 19, 11.59am-12.04pm.
• Manawatū Locksmith Palmerston North (50A Princess St) Wednesday January 19, 11.07am-11.12am