James Liu has always considered himself a patriot.

       With a lump in his throat, he watched a military parade on National Day, China’s birthday, that showed a once backward nation that had become strong and powerful. He got goose bumps watching “Wolf Warrior 2,” a “Rambo”-like Chinese blockbuster featuring a superhero veteran who single-handedly rescues his countrymen trapped abroad.

       When China came under attack online, Mr. Liu was one of the legions of Chinese students studying abroad who posted in its defense. He condemned the pro-democracy protests in Hong Kong, which he saw as an effort to split a uniting China. After President Trump called the coronavirus the “Chinese virus,” Mr. Liu turned to Twitter to correct those who used the term.

       “I was a real little pink,” he said, using a somewhat derogatory term for the young, Communist-red Chinese nationalists who use the internet as a patriotic battleground to fight those who disparage China.

       Then Mr. Liu, 21, discovered that the country he had long defended didn’t want him back.

       The fresh graduate from a Midwestern university had become one of an untold number of Chinese people stranded abroad by the coronavirus pandemic. Flights had vanished. Tickets home were outrageously expensive. The Chinese government, fearful that people like him would bring the virus with them, restricted international flights and told its expatriates to stay put.

       When overseas students went online to question why they couldn’t fly home, people in China told them to stay away. The students, they said, were spoiled brats who could jeopardize China’s success in containing the epidemic.

       Mr. Liu and many other countless Chinese people stranded overseas are, for the first time, running afoul of one of their country’s bedrock political principles: National interests come before an individual’s needs. That may sound reasonable, even logical, but it differs sharply from the sentiment in places, like the United States and elsewhere, where the rights of the minority are supposed to be protected.

       In this case, the stranded students and workers have become a minority group that is expected to sacrifice for the benefit of the majority. That puts them among the ranks of government critics and the Hong Kong pro-democracy protesters — people they have long battled online.

       Some of the little pinks are rethinking their relationship with the country — which, in the Chinese context, is the nation, the government and the Communist Party all in one.

       “My feelings are increasingly complicated,” Mr. Liu wrote on the social media platform Weibo in mid-May. “The country I loved doesn’t want me back.” Reading the many critical social media posts against overseas students like him, he felt as if he had been “beaten up badly,” he told me in a phone interview.

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       Their views could someday help shape China’s relationship with the world. Some will grow up to be leaders in business, academia or other institutions. They will most likely remain patriots, but they will have a more nuanced view of their country. And they may not be so quick to believe what they hear from their government.

       “Can you imagine what it was like when one day someone told you what you believed firmly wasn’t actually true?” Mr. Liu said.

       Daisy Leng, a third-year exchange student at Troy University in Alabama who finished her program but struggled to get a plane ticket home, wrote on Weibo that she truly loved her country and had fought against people who dared to smear China. But after four flight cancellations because of government restrictions, she was frustrated.

       “My heart had turned cold,” she wrote, adding a broken-heart emoticon.

       It isn’t clear how many are in a similar predicament. Mr. Liu and Ms. Leng are among more than 1.4 million Chinese students who were living in foreign countries as of April 2, with nearly one-third in the United States.

       Many didn’t rush home in February or March because the coronavirus situation looked worse at home. Others wanted to finish the semester rather than return home and take classes online with a punishing time difference. Some listened to the Chinese government, which told them to stay safe but stay put.

       Then the pandemic hit the rest of world. China’s aviation regulator began limiting how often foreign airlines could fly to the country. Chinese carriers flew abroad but with limited capacity. At the same time, less prosperous countries like India were organizing pickups for their stranded citizens.

       Many Chinese students went to the official Weibo account of China’s aviation regulator to plead and to protest canceled flights and high ticket prices. For them, China was like a beautiful but unattainable dream.

       “This is a time of prosperity, like you wished for,” said many, quoting a state media catchphrase urging Chinese people to feel grateful for living in a successful country.

       Many of the students belong to what might be the most nationalistic generation since China opened up to the world more than four decades ago. They grew up amid tightening censorship and increasingly strident propaganda. In school, they were taught incessantly that China was humiliated for a century by Western countries.

       Exposure to foreign cultures and languages has not made many of them more receptive to foreign ideas. Social media, especially WeChat, is so powerful that they mostly live in a China bubble in foreign lands.

       And the Communist Party has mastered the art of stirring their patriotism. One of its success stories is “Wolf Warrior 2,” the 2017 action movie that became China’s biggest hit and stirred people like Mr. Liu.

       Near the end of the movie, after a long shot of the Chinese veteran in an African nation waving his country’s flag, a sentence is typed out word by word on the back of a red Chinese passport: “Citizens of the People’s Republic of China, don’t give up when you encounter dangers abroad! Please remember, behind you stands a strong motherland!”

       For many of these students, these words sound empty now. “In the real world, there’s no wolf warrior coming to my rescue,” a Chinese student in Japan posted on Weibo.

       In early April, Mr. Liu bought a Delta Air Lines ticket for about $900 for a June flight to Shanghai. Then Delta’s flight was canceled when the Chinese authorities restricted U.S. carriers.

       The Coronavirus Outbreak

       Frequently Asked Questions and Advice Updated June 22, 2020

       Is it harder to exercise while wearing a mask?

       A commentary published this month on the website of the British Journal of Sports Medicine points out that covering your face during exercise “comes with issues of potential breathing restriction and discomfort” and requires “balancing benefits versus possible adverse events.” Masks do alter exercise, says Cedric X. Bryant, the president and chief science officer of the American Council on Exercise, a nonprofit organization that funds exercise research and certifies fitness professionals. “In my personal experience,” he says, “heart rates are higher at the same relative intensity when you wear a mask.” Some people also could experience lightheadedness during familiar workouts while masked, says Len Kravitz, a professor of exercise science at the University of New Mexico.

       I’ve heard about a treatment called dexamethasone. Does it work?

       The steroid, dexamethasone, is the first treatment shown to reduce mortality in severely ill patients, according to scientists in Britain. The drug appears to reduce inflammation caused by the immune system, protecting the tissues. In the study, dexamethasone reduced deaths of patients on ventilators by one-third, and deaths of patients on oxygen by one-fifth.

       What is pandemic paid leave?

       The coronavirus emergency relief package gives many American workers paid leave if they need to take time off because of the virus. It gives qualified workers two weeks of paid sick leave if they are ill, quarantined or seeking diagnosis or preventive care for coronavirus, or if they are caring for sick family members. It gives 12 weeks of paid leave to people caring for children whose schools are closed or whose child care provider is unavailable because of the coronavirus. It is the first time the United States has had widespread federally mandated paid leave, and includes people who don’t typically get such benefits, like part-time and gig economy workers. But the measure excludes at least half of private-sector workers, including those at the country’s largest employers, and gives small employers significant leeway to deny leave.

       Does asymptomatic transmission of Covid-19 happen?

       So far, the evidence seems to show it does. A widely cited paper published in April suggests that people are most infectious about two days before the onset of coronavirus symptoms and estimated that 44 percent of new infections were a result of transmission from people who were not yet showing symptoms. Recently, a top expert at the World Health Organization stated that transmission of the coronavirus by people who did not have symptoms was “very rare,” but she later walked back that statement.

       What’s the risk of catching coronavirus from a surface?

       Touching contaminated objects and then infecting ourselves with the germs is not typically how the virus spreads. But it can happen. A number of studies of flu, rhinovirus, coronavirus and other microbes have shown that respiratory illnesses, including the new coronavirus, can spread by touching contaminated surfaces, particularly in places like day care centers, offices and hospitals. But a long chain of events has to happen for the disease to spread that way. The best way to protect yourself from coronavirus — whether it’s surface transmission or close human contact — is still social distancing, washing your hands, not touching your face and wearing masks.

       How does blood type influence coronavirus?

       A study by European scientists is the first to document a strong statistical link between genetic variations and Covid-19, the illness caused by the coronavirus. Having Type A blood was linked to a 50 percent increase in the likelihood that a patient would need to get oxygen or to go on a ventilator, according to the new study.

       How many people have lost their jobs due to coronavirus in the U.S.?

       The unemployment rate fell to 13.3 percent in May, the Labor Department said on June 5, an unexpected improvement in the nation’s job market as hiring rebounded faster than economists expected. Economists had forecast the unemployment rate to increase to as much as 20 percent, after it hit 14.7 percent in April, which was the highest since the government began keeping official statistics after World War II. But the unemployment rate dipped instead, with employers adding 2.5 million jobs, after more than 20 million jobs were lost in April.

       My state is reopening. Is it safe to go out?

       States are reopening bit by bit. This means that more public spaces are available for use and more and more businesses are being allowed to open again. The federal government is largely leaving the decision up to states, and some state leaders are leaving the decision up to local authorities. Even if you aren’t being told to stay at home, it’s still a good idea to limit trips outside and your interaction with other people.

       What are the symptoms of coronavirus?

       Common symptoms include fever, a dry cough, fatigue and difficulty breathing or shortness of breath. Some of these symptoms overlap with those of the flu, making detection difficult, but runny noses and stuffy sinuses are less common. The C.D.C. has also added chills, muscle pain, sore throat, headache and a new loss of the sense of taste or smell as symptoms to look out for. Most people fall ill five to seven days after exposure, but symptoms may appear in as few as two days or as many as 14 days.

       How can I protect myself while flying?

       If air travel is unavoidable, there are some steps you can take to protect yourself. Most important: Wash your hands often, and stop touching your face. If possible, choose a window seat. A study from Emory University found that during flu season, the safest place to sit on a plane is by a window, as people sitting in window seats had less contact with potentially sick people. Disinfect hard surfaces. When you get to your seat and your hands are clean, use disinfecting wipes to clean the hard surfaces at your seat like the head and arm rest, the seatbelt buckle, the remote, screen, seat back pocket and the tray table. If the seat is hard and nonporous or leather or pleather, you can wipe that down, too. (Using wipes on upholstered seats could lead to a wet seat and spreading of germs rather than killing them.)

       What should I do if I feel sick?

       If you’ve been exposed to the coronavirus or think you have, and have a fever or symptoms like a cough or difficulty breathing, call a doctor. They should give you advice on whether you should be tested, how to get tested, and how to seek medical treatment without potentially infecting or exposing others.

       How do I get tested?

       If you’re sick and you think you’ve been exposed to the new coronavirus, the C.D.C. recommends that you call your healthcare provider and explain your symptoms and fears. They will decide if you need to be tested. Keep in mind that there’s a chance — because of a lack of testing kits or because you’re asymptomatic, for instance — you won’t be able to get tested.

       Prices rose. One of his friends paid $10,000 for a seat in coach. Mr. Liu expects his first job will pay him a little over $1,000 a month. Studying in the United States had cost his parents a lot of money.

       In the following weeks, Mr. Liu didn’t sleep well, getting by with five or six hours a night. He joined chat groups that exchanged information about flights. He found one ticket for $4,000 — a reasonable price by then — that would take him through New York, Mexico City and Tokyo. His mother vetoed the plan. Too many transfers would increase his exposure to the virus.

       Finally, he booked a flight through Los Angeles and Seoul, South Korea, to the Chinese city of Xiamen, 370 miles from his hometown. Cost: $2,500.

       “I felt much better now that I got the ticket,” he said. “I almost started questioning the meaning of life.”

       While the students were outspoken in their anonymous social media comments, they were more reserved in interviews. Mr. Liu, for example, focused his frustration on China’s aviation regulator, which recently backed down after U.S. officials challenged its limits on foreign airlines. Ms. Leng, of Troy University, said she understood the regulator’s motivations.

       But some admitted to what might be a new feeling: fear. The student from Japan who invoked “Wolf Warrior 2” said she feared retribution by the Chinese government if she spoke to me.

       Then she invited me into a WeChat group of nearly 500 Chinese students exchanging information about flights, visas, schools and frustrations. They told one another not to give news interviews, not even to the Chinese media, for fear of government punishment.

       When they sometimes couldn’t help curse the government or the policy, someone would quickly warn that they had better shut up or risk losing their WeChat accounts or even being invited for a chat once they’re back in China.

       One student, after being warned, posted an emoticon of the 12 core socialist values that every Chinese citizen is supposed to live by, posting it five times in a row, as if pledging his loyalty to the surveillance state.

       “I grew up under the red flag and received the red education,” Mr. Liu said to me. “But what can I say now?”