Despite testing positive for COVID-19, New Zealand Prime Minister Jacinda Ardern said she still plans to visit the United States later this month for a trade trip and to deliver the commencement speech at Harvard University.

Ms. Ardern said she was disappointed to miss several important political announcements over the coming week, including the release of the government’s annual budget and a plan to reduce greenhouse gas emissions, in an Instagram post on Saturday.

“I’m gutted to miss being there in person,” she wrote, “but will be keeping in touch with the team and sharing some reckons from here.”

Ms. Ardern, who has been fully vaccinated, has been quarantined at her Wellington home since her fiancé Clarke Gayford tested positive for the virus on Sunday. People in New Zealand must isolate for seven days if someone in their household tests positive for HIV.

Ms. Ardern said she had a weak positive rapid antigen test on Friday night and a strong positive test the next morning.

She also revealed that on Wednesday, the couple’s three-year-old daughter, Neve, tested positive for the virus.

Ms. Ardern wrote, “Despite my best efforts, I’ve unfortunately joined the rest of my family and have tested positive for COVID 19.”

“To anyone else isolating or dealing with COVID, I hope you take good care of yourselves!” she said.

Ms. Ardern did not mention her symptoms in her post, though her office said in a statement that she began experiencing them on Friday.

Ms. Ardern joins a long list of world leaders who have caught the virus. British Prime Minister Boris Johnson was one of the first and most serious cases, being hospitalised for a week in April 2020 before vaccines were available.

When the pandemic first broke out, New Zealand closed its borders and imposed strict lockdowns, allowing it to completely eradicate several outbreaks of the virus while keeping life as normal as possible. However, as outbreaks became more difficult to contain and the majority of the population was vaccinated, the country’s COVID-zero policy was eventually abandoned.

The Omicron variant has rapidly spread throughout New Zealand, resulting in the country’s first major outbreak this year.