Hokkaido, the northernmost Japanese main islands, has lifted its lockdown measures on March 19 so that businesses and schools could reopen. They decided to do so after their new cases fall to one or two per day.

However, the island was struck by a second wave of COVID-19 pandemic after 26 days of lifting its lockdown. Now, the island has re-enforced its lockdown after recording 135 new cases in just one week.

Regrets after the early lifting of the lockdown

"Now I regret it, we should not have lifted the first state of emergency," said Dr. Kiyoshi Nagase, the chairman of the Hokkaido Medical Association, in an interview with TIME.

He admitted that it might not be until next year that the lockdowns can be safely lifted because of the severity of the pandemic. Although the government has thought of and assessed how immigration could impact the spread of the coronavirus on the island, they have failed to consider the effects of domestic migration.

The lockdown lift was too early, and at the time, authorities do not have enough information and adequate understanding of the pandemic, said Yoko Tsumakoto, a professor of infection control at the Health Sciences University of Hokkaido.

More so, with the available information that time, those new cases were down to one or two a day, it looks like the governor's decision in lifting the state of emergency was the right choice. It is only now that they realize that the decision made was wrong, but then it seemed the best thing to do, she told The Telegraph.

Despite this, health officials learned a lesson on lifting lockdowns. Tsumakoto said that authorities should wait as long as possible to get accurate data on infection numbers and to be extremely cautious once the rules are relaxed. In time, the lockdowns and state of emergencies will be lifted.

Additionally, the government should be ready to move quickly and put restrictions back in place once the symptom of another surge begins.

On Tuesday, Hokkaido reported 38 new cases, making its total number of infections to 688, ranking as the sixth-highest number of cases in Japan. The island's death toll has also reached to 27 total cases after one person has died recently.

How did the infection start in Hokkaido?

Home to 5.3 million people, Hokkaido became the case study in virus-management before they lifted the lockdown. The experts now hope to learn lessons from lifting measures too quickly.

The island's coronavirus cases can be traced back to its Sapporo Snow Festival in February-before its initial lockdown- which attracted 2 million people. One Chinese tourist from Wuhan was being treated on the island for coronavirus during the festival.

By March 12, there are already 118 people being treated for the virus in Hokkaido, making it the worst-hit of all Japan's 47 prefectures.

In total, Japan is under lockdown until May 6, but the country has already recorded 13,576 cases and 376 deaths. Although the lockdown possibly is extended for another month, according to Nikkei Business Daily.