Beijing and New Zealand had both declared themselves Covid-19-free by mid-June, life returning to an enviable normality of schools and shops, work and human contact. It didn’t last long. Last week, parts of the Chinese capital went back on a “wartime” footing after a cluster of cases emerged linked to the city’s biggest wholesale food market. Movement restrictions are back and residents have already been warned against leaving the city. Schools are closed. In New Zealand, two British women who had flown in to see a dying relative tested positive after they had been released from quarantine for compassionate reasons. The outbreaks have brought home the stark choices facing leaders who have successfully stamped out the virus or contained its transmission. If they want to hold on to that coveted status, their countries face months, perhaps years, sealed off from the world in a way unprecedented in modern times. “They can maintain containment but doing so will probably require strict observance of quarantines by travellers,” said Prof Lindsay Wiley, director of the health law and policy program at American University Washington College of Law. “Testing of travellers upon entry may not be sufficient, given the incubation period and the risk of false negatives. But lengthy travellers’ quarantines are problematic for economies that depend on tourism and also interfere with business travel.” At present the borders of both China and New Zealand are only open to their citizens and a tiny number of foreigners granted special exemptions by authorities. Both require 14 days’ self-isolation for all arrivals so, even if restrictions on entry were eased, that effectively rules out most short-term visits for fun or work. Their citizens are largely cut off from the rest of the world; those willing to risk travel abroad must also be able to afford two weeks’ isolation on their return. Nor will vaccines necessarily provide a solution to these countries’ economic dilemmas, Wiley said. “If the protection a vaccine provides is imperfect, as is true for most vaccines, it also will depend on how widely distributed vaccines are and how many people are comfortable becoming vaccinated.” Both countries have launched exhaustive testing and tracing efforts to reach all possible contacts of those infected; New Zealand has also cancelled all compassionate exceptions to its quarantine measures. China had taken extra measures to protect its capital from the beginning of the outbreak months ago. The city is not just home to the country’s mostly elderly leadership, it also has huge symbolic importance. That sensitivity remains; within days of the outbreak emerging, there were troops around the wholesale market at its centre. Now over 100 cases have been confirmed by mass testing, the city government has described the situation as “extremely severe”, raised the emergency alert level, ordered all schools closed and a halt to all but urgent travel out of the city. Unlike with the cases in New Zealand, there is no clarity about where the outbreak originated, raising fresh concerns about how it has re-emerged – long after the 14-day quarantine period since the last known locally transmitted case. Initial reports said contaminated samples had been found on cutting boards used to handle imported salmon, sparking a panic that led to the fish being pulled from supermarket shelves, even though it cannot catch or transmit the disease. The new shutdown will be another blow to China’s economy, already devastated by Covid-19. The coronavirus shutdown brought an abrupt halt to decades of growth, that had continued even through Tiananmen, Sars and the global financial crash. Keeping borders closed could push foreign investors – some already concerned about supply chain vulnerability – to look to other countries for both factories to manufacture their products, or markets to sell them into. But not everything manufactured in China can easily be shifted abroad. “At the end of the day, there is a calculation, what are these foreigners really going to do?” said Prof Steve Tsang, director of the Soas China Institute. “China is still so much better a location for so many of them, I think the implicit threat is not being taken very seriously. You will need to see significant number of them relocating for it to be taken seriously.”