The new community case in New Zealand - the country's first for 67 days - marks the first time one of the new, more dangerous variants of COVID-19 has wriggled past our border.
The woman, who has visited at least 30 locations around Northland and northern Auckland since being released from managed isolation on January 13, has B.1.351, a South African strain of coronavirus.
The source of the new infection, which was confirmed on Monday, is believed to be a result of exposure to a fellow returnee staying at the Pullman Hotel earlier this month.
In a press conference on Monday afternoon, Dr Ashley Bloomfield revealed the woman had contracted the South African variant of the virus.
"There is limited epidemiological data available to date," the Director-General of Health said of the strain.
"What we know so far is that it may be more transmissible, but that's not as clear as the information about the variant first identified in the UK. There is some evidence that this variant may evade some aspects of the body's immune response."
Why the South African COVID-19 strain is worse than normal
The South African variant is one of three new strains causing concern for health authorities, alongside the B.1.1.207 variant in the UK and the B.1.1.248 variant in Brazil.
Researchers in South Africa have noted that the B.1.351 strain is more prevalent among young people with no underlying health conditions, and more often results in serious illnesses in these cases.
Some researchers - including epidemiologist Professor Salim Abdool Karim, co-chair of the health ministry's scientific committee - believe the variant may be as much as 50 percent more contagious than the original coronavirus.
The new variant, South Africa's health department believes, is behind a second wave of COVID-19 that has seen the daily average of new cases in the nation of 58 million surge from about 2000 a day in mid-November to more than 18,000 a day in mid-January.
And those aren't the only concerns. B.1.351 may also be less responsive to vaccines, UK's Health Secretary revealed in an online webinar with British travel agents last week.
"There is evidence in the public domain - although we are not sure of this data so I wouldn't say this in public - that the South African variant reduces by about 50 percent the vaccine efficacy," Matt Hancock said.
"If we vaccinated the population, and then you got in a new variant that evaded the vaccine, then we'd be back to square one."
The B.1.351 strain, first discovered in Nelson Mandela Bay in October 2020, is caused by a series of mutations of the virus's spike protein. Mutations occur when viruses replicate, and can be both advantageous and disadvantageous to the survival of the microorganism.
The UK, Brazilian and South African strains of COVID-19 are advantageous to its survival, as early research suggests they transmit from person to person more easily than the original strain.