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       In this image made from video, New Zealand Prime Minister Jacinda Ardern speaks during a news conference in Wellington, on Aug. 17.

       The Associated Press

       Four new cases of COVID-19 have been confirmed in the country including one Auckland hospital worker, New Zealand’s Prime Minister Jacinda Ardern told Radio New Zealand on Wednesday.

       That takes the total number of confirmed cases in the country to five. Ms. Ardern said all cases are have now been confirmed as Delta variant.

       New Zealand’s government took drastic action Tuesday by putting the entire country in strict lockdown for at least three days after finding a single case of coronavirus infection in the community.

       Ms. Ardern, in announcing the measures, invoked some of the stirring rhetoric she used early in the pandemic by urging the “team of five million” – New Zealand’s population – to go hard and early in trying to eliminate the latest outbreak.

       “We have seen what happens elsewhere if we fail to get on top of it,” Ms. Ardern said. “We only get one chance.”

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       She said Auckland, where the infected man lives, and Coromandel, where he had visited, would go into a full lockdown for seven days and the remainder of the country for three days while health experts tried to find the source of his infection.

       The developments on Tuesday prompted people to line up outside supermarkets to stock up on essential items and sparked a sharp drop in the value of the New Zealand dollar.

       New Zealand had managed to stamp out the virus, and the last outbreak was in February. But Ms. Ardern had been warning that the contagiousness of the Delta variant would likely require more drastic action than previous outbreaks.

       New Zealand has also been slower than other developed countries to inoculate its population, leaving it vulnerable to outbreaks. Only 32 per cent of people have had at least one shot and 18 per cent are fully vaccinated.

       And officials have been viewing a growing outbreak in nearby Sydney with alarm, saying they don’t want to make the same mistakes by waiting too long to impose strict measures.

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       Health officials said genome testing would not verify until Wednesday whether the infected 58-year-old man had the Delta variant, although they were working under the assumption he does.

       Officials said they could not immediately find a connection between the man and the handful of people who have tested positive while isolating in quarantine after arriving from abroad. The border is seen as the most likely source of any outbreaks.

       The move into the strictest lockdown underscored the vastly different approach New Zealand has taken to the virus than most other countries, which are attempting to suppress its spread rather than eliminate it entirely.

       New Zealand has reported just 26 virus deaths since the pandemic began.

       The lockdown takes effect from just before midnight Tuesday. It requires people to remain at home and avoid others. Most people can leave only to buy groceries or exercise. The country’s vaccination program had been accelerating but has been suspended for two days because of the outbreak.

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