It should not have come as a surprise. Life had already been upended in China. Iran and Italy have been reeling for a month. And yet it still felt sudden, this week, when walls were raised across the world, entire societies were quarantined and billions of people realised they had crossed a dividing line: from life before coronavirus to after.

After weeks of governments prevaricating over whether to ban mass gatherings, close businesses or seal borders, restrictions came in a flurry. “We are at war,” announced the French president, Emmanuel Macron. But without adequate weapons to fight the virus, let alone enough hospital beds or ventilators, this was the week the world beat a tactical retreat.

Spain’s 46 million citizens were in lockdown by Sunday morning. Its death toll would double by the end of the day to 288. People had partied in Dublin’s Temple Bar on Saturday night. It was a last hurrah: the neighbourhood’s water holes were indefinitely closed the following day.

The same day, Germany closed its borders to France, Switzerland and Austria, whose chancellor, Sebastian Kurz, warned the country the next weeks would be “challenging, difficult and painful”. More than 1,400 people had died in Italy.

In Mafraq, a small city in Jordan, a Syrian girl, Reem Ahmed, missed school for the first time since September. Though aged 11, the past six months were the only time she had ever spent in a classroom, part of a humanitarian programme to steer refugee children out of work and into education. But classes across Jordan had been suspended to prevent the spread of the coronavirus.

Reem spent the first Sunday at home crying, her father said. “I had friends at school and learned from my teachers there,” she said.

Facebook Twitter Pinterest Cars are sanitised on the streets of Amman in Jordan. Photograph: Andre Pain/EPA

In Las Vegas, Rocky Jedick, an emergency room doctor, got off his sixth shift in a row. The last had included a patient with serious lung issues. “Based on the way they were presenting I thought it was a 99% chance, if not higher, that this person had it,” he said.

The patient’s results would not be known for a few days. In his head, Jedick went over every moment of contact he had had with the person. “I knew I needed to be really, really careful. I double-checked myself, made sure everything was 100%.”

On Monday, the worldwide death toll crossed 7,000. Canada closed its borders to all foreigners except for Americans. Boris Johnson and Donald Trump struck newly urgent tones, asking people to avoid going to bars or theatres, and to self-isolate for two weeks if they felt sick. “Now is the time for everyone to stop non-essential contact with others and to stop all unnecessary travel,” Johnson said.

A research team at Imperial College released a report that is said to have contributed to the policy shifts. Without significant changes in people’s behaviour, it said, the British death toll could cross half a million, with 2.2 million dead in the US. Social distancing measures would need to continue until a vaccine was found, it added. That would be at least 18 months away.

In the Bangladeshi capital, Dhaka, a jeans factory owner named Mostafiz Uddin received an email from a western buyer. Stop all shipments immediately, it said. “I got very upset,” Uddin said. “I had four trucks of goods which were on their way to being shipped. I brought them back to the factory. When the buyer says they can’t ship it, we can’t do anything. Everything is in their hands.”

In Tabriz, a city in north-western Iran, a young medical researcher named Sara Amiri asked a colleague to test her for coronavirus. “I had had a headache for days and one of my colleagues, a doctor who used to visit patients, had tested positive for the virus,” she said.

Quick guide What to do if you have coronavirus symptoms in the UK Show Hide Symptoms are defined by the NHS as either: a high temperature - you feel hot to touch on your chest or back

a new continuous cough - this means you've started coughing repeatedly NHS advice is that anyone with symptoms should stay at home for at least 7 days.

If you live with other people, they should stay at home for at least 14 days, to avoid spreading the infection outside the home. After 14 days, anyone you live with who does not have symptoms can return to their normal routine. But, if anyone in your home gets symptoms, they should stay at home for 7 days from the day their symptoms start. Even if it means they're at home for longer than 14 days. If you live with someone who is 70 or over, has a long-term condition, is pregnant or has a weakened immune system, try to find somewhere else for them to stay for 14 days. If you have to stay at home together, try to keep away from each other as much as possible. After 7 days, if you no longer have a high temperature you can return to your normal routine. If you still have a high temperature, stay at home until your temperature returns to normal. If you still have a cough after 7 days, but your temperature is normal, you do not need to continue staying at home. A cough can last for several weeks after the infection has gone.

Staying at home means you should: not go to work, school or public areas

not use public transport or taxis

not have visitors, such as friends and family, in your home

not go out to buy food or collect medicine – order them by phone or online, or ask someone else to drop them off at your home You can use your garden, if you have one. You can also leave the house to exercise – but stay at least 2 metres away from other people. If you have symptoms of coronavirus, use the NHS 111 coronavirus service to find out what to do. Source: NHS England on 23 March 2020

By Tuesday, Idris Elba had the virus. Tom Hanks and his wife, Rita Wilson, were discharged from hospital. Australia put out an unprecedented call for its citizens to return home. Iran freed tens of thousands of prisoners including the British national Nazanin Zaghari-Ratcliffe. More than 1,000 prisoners in Brazil escaped. West Virginia recorded its first case of the virus, meaning all 50 American states were infected. The Taj Mahal in India was indefinitely closed.

In Melbourne, Australia, a retiree named Andrew Cameron went to the supermarket. He went early, during a specially designated shopping time reserved for older people and those with disabilities.

“The shelves were bare, no toilet paper, no paper towels, pasta’s gone, a lot of frozen food was gone,” he said. “A lot of vegetarian food, interestingly. Even the hard tofu, can you imagine?”

He took two bottles of hand sanitiser to the self-checkout, but encountered a problem. “The machine said no, you’re only allowed one,” he said.

Neither the checkout attendant nor the store manager could overrule the machine. Cameron, 76, argued his case anyway, while his wife Ursula stood behind him, trying to make sure he maintained the recommended 1.5-metre distance from other people. “She was saying, step back Andy, step back.”

Ursula has since banned him from the supermarket. “Which is sad for me, because I like to shop,” he said.

Facebook Twitter Pinterest A near-empty shopping mall in Melbourne, Australia. Photograph: Asanka Ratnayake/Getty Images

On Wednesday evening, Angela Merkel told Germans they were facing their biggest crisis since the second world war and reunification. “The situation is serious,” she said. “Take it seriously.”

Europe had already closed its external borders to most of the world. Italy announced its highest single-day death toll: 475. Parisians gathered on their balconies to applaud the efforts of medical staff. The first deaths were recorded in Pakistan, Bangladesh and Burkina Faso. The World Health Organization warned Africa to “wake up” and expect the worst.

Uddin, in Bangladesh, received another email. “Please cancel any new orders,” it said. It did not say for how long. Shift lengths at his factory are already being cut from 10 hours to eight. Four million people, mostly women, work in Bangladesh’s garment industry.

“This uncertainty will kill us,” he said. “I will be able to pay my workers for the first month – I’ll arrange something. But the next month, and the one after? No, there is no solution.”

In Iran, Amiri started working from home. “I’m fine, I just have asthma and a headache, and yesterday I couldn’t eat anything,” she said.

She was more worried about shortages of masks and protective material at hospitals and pharmacies. “I’m not sure how much is the result of sanctions, and how much is weakness from our government,” she said.

On Thursday, deaths in Italy crossed 3,400, exceeding China’s toll. Beijing said it had recorded no new cases among its population for the first time. Confirmed cases in Spain had more than doubled since the beginning of the week to at least 17,000.

India’s Narendra Modi urged his country’s 1.3 billion citizens to observe a national curfew on Sunday, while the UN warned it was only a matter of time until the virus reached Idlib, where nearly 1 million refugees were living in makeshift accommodation and overcrowded tents.

In Jordan, Reem spent the day watching the sports channel on television, which had been repurposed to broadcast school lessons. Her sister Malaka, 12, had never been to school; she spent the day as usual, picking fruit at a nearby farm for about £5 a day. “We need the money to live off,” Fawaz, her father, said. “Life is hard otherwise.”

If school did not resume soon, he added, Reem would have to join her. “If things don’t improve, she’ll have to go,” he said.

In Las Vegas, Jedick worked on flow charts to help the hospital deal with a glut of patients. “We have a bit of a panic where anybody with respiratory symptoms or a fever is coming in and flooding the ER,” he said.

Facebook Twitter Pinterest Santa Monica Pier in Los Angeles has shut down after California issued an emergency order. Photograph: AaronP/Bauer-Griffin/GC Images

His facility was planning to set up tents outside where incoming patients could be triaged and treated if necessary. “We’re looking at the numbers coming out of Italy and China and assuming we could see an exponential growth of this thing.”

The results were in: the patient he had treated on Sunday had coronavirus. Jedick would be back in the ward at the weekend. “Healthcare workers are, for many reasons, at higher risk,” he said. “Someone has to get it. I could be that person. But my mind doesn’t work like that. I’m optimistic and I don’t think it’ll be me.”

On Friday, the official death toll passed 10,000. Argentina went into lockdown, Haiti closed its borders and California’s 40 million residents were told to stay in their homes. The US state’s governor estimated 56% of Californians would contract the virus within the next eight weeks.

France banned cycling and said people could only walk up to 2km from their homes. Cirque du Soleil, the entertainment company, said it would temporarily lay off 95% of its staff. The number of infected people around the world had increased by 50% since Monday.

In Tabriz, Amiri received a phone call. “I was informed that I’m positive,” she said. “I don’t feel anything right now, I’m just worried about my family, even though I avoided them these last few days.”

Her husband was isolating with her and keeping her spirits high, she said. “He tells me: ‘You are so strong, coronavirus is going to regret getting anywhere near you’.”

Additional reporting by Akhtar Mohammad Makoii and Jassar Al-Tahat