Epidemiologist Michael Baker says there’s a small chance of a Covid-19 outbreak in Auckland due to the likelihood of a missing case linking two border workers.
Baker says the length of time between Case A, a Grand Millennium MIQ cleaner, and Case B, a Grand Millennium MIQ security worker, being infected means there is likely another case which has been missed.
Case A tested positive on March 21, while Case B tested positive 18 days later.
"I think given the time delay there almost has to be another case in between these cases because the time interval is so long it would suggest an undetected case there," Baker told 1 NEWS.
He added many cases don’t go on to cause outbreaks, but there is still cause for concern.
"If there is an undetected case then it can’t be contact traced, so there is that slight possibility that this missing case could’ve infected others and there may be a small outbreak that is still undetected in the community."
The warning comes as last night Case C was announced in the Grand Millennium cluster, another security worker who is a close contact of Case B.
All three cases - A,B and C - have been genomically linked to a returnee who tested positive on March 13 in managed isolation.
It was also revealed today that Case B had not been tested for Covid-19 since at least mid-March, sparking an investigation into the lack of testing.
Director-General of Health Dr Bloomfield said the testing history of Case B was being investigated.
"What we do know is that since the middle of March ... that Case B hadn't had a test until this one last week which showed the positive result."
MIQ's Brigadier Jim Bliss was not able to tell media when Case B's last test prior to April 6 took place.
"We are concerned it wasn't in accordance with our 14 day testing regime."
Both Case B and Case C had also not received vaccinations.