During Ministry of Health press conferences, you may have heard COVID-19 Response Minister Chris Hipkins refer to the different levels of contacts - close, casual and casual-plus.
But what do they actually mean?
A close contact is someone who is more likely to be at higher risk of being infected because they have spent time in close proximity to a confirmed case during the case's infectious period.
"Close contacts are the ones that we focus more urgently on," Hipkins said at a press conference on Tuesday.
There's also a difference between a casual and casual-plus contact. Due to the risk of the more transmittable South African variant, casual contacts are being referred to as 'casual-plus'.
"A casual or casual-plus contact is someone who has had only limited exposure to a confirmed case, usually by being in the same location of interest either at the same time or soon after a confirmed case," a Ministry of Health spokesperson told Newshub on Wednesday.
"In some specific situations, we will ask casual contacts to take additional steps where there may have been a higher risk of transmission - that's what we refer to as casual-plus."
So far 154 people have been identified as casual-plus contacts to the Northland woman who tested positive for COVID-19.
The Northland community case marks the first time South African strain B.1.351 has passed our border.
Researchers in South Africa have noted that the B.1.351 strain is more prevalent among young people with no underlying health conditions.
Epidemiologist Professor Salim Abdool Karim believes the variant may be as much as 50 percent more contagious than the original coronavirus.