SİNGAPUR – Aşıların pandemiden çıkış bileti olması gerekiyordu. Ancak Singapur’da işler plana göre gitmedi.

Güneydoğu Asya şehir devleti, koronavirüsle ilk mücadelesinde yaygın olarak bir başarı öyküsü olarak kabul edildi. Sınırlarını kapattı, agresif bir şekilde test edildi ve izlendi ve Asya’da aşı siparişi veren ilk ülkelerden biriydi.

Üst düzey bir politikacı halka, aşamalı bir yeniden açma için kriterin yüzde 80 aşılama oranı olduğunu söyledi. Singapur şu anda nüfusunun yüzde 83’ünü tamamen aşıladı, ancak açılmak yerine tam tersini yapıyor.

Eylül ayında, vakaların her sekiz ila 10 günde bir ikiye katlanmasıyla hükümet, toplantılara kısıtlamalar getirdi. ABD, vatandaşlarının ülkeye seyahat etmeyi yeniden gözden geçirmesi gerektiğini söyledi. Birçok hastanenin acil servislerinde uzun kuyruklar oluşmaya başladı. İnsanlara bir kez daha evden çalışmaları gerektiği söylendi.

Ülkenin deneyimi, pandemideki büyük salgınlarla uğraşmak zorunda kalmadan yeniden açılma stratejileri izleyen diğer ülkeler için ayık bir vaka çalışması haline geldi. Şehir devletinin aşılanma oranı belirli bir seviyeye ulaştığında yeniden açılacağına inanan Singapur sakinleri için, aşılar yeterli olmazsa yeniden açmak için ne yapılması gerektiği konusunda bir kamçılanma ve dırdırcı sorular vardı.

“In a way, we are a victim of our own success, because we’ve achieved as close to zero Covid as we can get and a very, very low death rate,” said Dr. Paul Tambyah, an infectious diseases specialist at National University Hospital. “So we want to keep the position at the top of the class, and it’s very hard to do.”

Singapore’s careful, some say overly cautious, approach to reopening contrasts with that of the United States and Europe, where vaccinated people are already gathering at concerts, festivals and other large events. But unlike Singapore, both of those places had to manage substantial outbreaks early in the pandemic.

Lawrence Wong, Singapore’s finance minister and a chair of the country’s Covid-19 task force, said the lesson for “Covid-naive societies” like Singapore, New Zealand and Australia is to be ready for large waves of infections, “regardless of the vaccine coverage.”

“Once you open up, more social interactions will happen,” he said. “And given the inherently highly transmissible nature of the Delta variant, you will get big clusters emerging.”

The vaccines have worked to keep most of the population out of the hospital, with 98.4 percent of cases presenting mild or no symptoms. The deaths have occurred mostly in seniors, usually with comorbidities, and account for 0.2 percent of the cases over the past 28 days. But the shots cannot protect against infection, especially when up against the Delta variant, Mr. Wong said.

“In Singapore, we think that you cannot just rely on vaccines alone during this intermediate phase,” he said. “And that’s why we do not plan an approach where we reopen in a big bang manner, and just declare freedom.”

The country is set to review its restrictions on Monday, two weeks after they were put into place, and to make adjustments depending on the situation in the community. In Mr. Wong’s vision of how the pandemic will play out in Singapore, people will continue to wear face masks. Travel is unlikely to be entirely free.Social distancing will remain, perhaps until 2024.

He stressed that Singapore was still on a path toward living with Covid and said he recognized that any form of tightening, no matter how small, would be met with anger and frustration because people are anxious to move on. “But we have to adjust based on the realities, based on the situation we are facing,” he said.

Last month, officials scrambled to set up community treatment facilities equipped with oxygen tanks and asked those with mild or no symptoms to recover at home. Many Singaporeans said there was confusion about what to do and that the government appeared ill prepared.

“If the health care system gets overwhelmed, that’s when we know from experience everywhere that doctors are unable to cope and you have death rates start to go up,” Mr. Wong said. “So we are trying very hard to avoid that.”

Several doctors have disputed the government’s claim that the health care system is under immense strain. Dr. Tambyah, who is also chairman of an opposition party that recently drew up an alternative strategy for dealing with the pandemic, said there was enough of a buffer in hospitals because Singapore had canceled all elective surgeries.

The problem for Singapore’s leaders, he said, is that they are “essentially doing a transition from zero Covid toward living with the virus.”

For many, the repeated tweaks to the restrictions have taken a toll. The number of suicides in 2020 was the highest since 2012, a trend that some mental health experts have attributed to the pandemic. People have called on the government to consider the mental health concerns caused by the restrictions.

“It’s just economically, sociologically, emotionally and mentally unsustainable,” said Devadas Krishnadas, chief executive at Future-Moves Group, a consultancy in Singapore. Mr. Krishnadas said the decision to reintroduce restrictions after reaching such a high vaccination rate made the country a global outlier.

“And, importantly, it moves Singapore in a complete 180 degrees, opposite direction from where the rest of the world is headed,” he said. “That brings us to the strategic question of where will this leave Singapore — if we don’t get off what I call the hamster wheel of opening and closing.”

Angeline Ng,a marketing manager,said this year was tougher than the last. Before her father died in May, she had to navigate the strict visitor limits in the hospital, which was emotionally taxing. In July, the government’s announcement that it would once again tighten social restrictions added to her weariness.

“I think a lot of times we are so focused on wanting to get good results that we just have tunnel vision,” she said.

Ms. Ng lives across from a testing center. Almost daily, she watched a constant stream of people go in for tests, a strategy that many public health experts say is a waste of resources in such a highly vaccinated country.

“Freedom Day — as our ministers have said — is not the Singapore style,” said Jeremy Lim, an associate professor at the National University of Singapore and an expert on health policy, referring to England’s reopening in the summer. But moving too cautiously over the potential disadvantages of restrictions is a “bad public health” strategy, he said.

The government should not wait for perfect conditions to reopen, “because the world will never be perfect. It’s so frustrating that the politicians are almost like waiting for better circumstances,” Dr. Lim said.

Sarah Chan, a deputy director at Singapore’s Agency for Science, Technology and Research, said she had a fleeting taste of what normal life was like when she arrived in Italy last month to visit her husband’s family.

No masks were required outdoors, vaccinated people could gather in groups, and Dr. Chan and her son could bop their heads to music in restaurants. In Singapore, music inside restaurants has been banned based on the notion that it could encourage the spread of the virus.

Dr. Chan said she was so moved by her time in Italy that she cried.

“It’s almost normal. You forget what that’s like,” she said. “I really miss that.”