LONDON — Once again, the world shuddered at news about President Trump. This time, it wasn’t something Mr. Trump said or did, but rather the announcement that he had tested positive for the coronavirus.
Mr. Trump is not the first world leader to be infected. Prime Minister Boris Johnson of Britain and President Jair Bolsonaro of Brazil both tested positive. And Mr. Johnson suffered a serious bout of Covid-19, ending up in an intensive care unit where, he said later, “things could have gone either way.”
But Mr. Trump, 74, is older and at higher risks than either of those men. The news of an American president contracting a potentially lethal virus carried global repercussions beyond that of any other world leader. Financial markets fell in Asia and looked set to open lower in Europe and the United States.
Expression of concerns and good wishes for Mr. Trump’s speedy recovery — as well as that of first lady Melania Trump — poured in from leaders in India, Britain and other countries.
“Wishing my friend @POTUS @realDonaldTrump and @FLOTUS a quick recovery and good health,” the prime minister of India, Narendra Modi, said in a tweet.
Britain’s housing secretary, Robert Jenrick, said, “All of us want to send our best wishes to President Trump, the first lady and the Trump family and wish them a speedy recovery.”
“We know what it’s like to have, in our case a prime minister who tested positive for Covid and setting aside politics we all want to see him and his wife get better soon,” Mr. Jenrick said on Sky News.
Some foreign commentators, however, took note of Mr. Trump’s cavalier handling of the pandemic, saying it was a grim reminder of a virus that drew on distinctions between rich or poor, weak or powerful.
Others suggested a degree of justice in his diagnosis, given his record of diminishing the threat of the virus, refusing simple precautions like wearing a face mask and holding campaign rallies without social distancing.
“When the president of the United States, the most powerful person in the world, can catch this, the virus has no boundaries,” said Wang Huiyao, the founder and president of the Center for China and Globalization, an influential research group in Beijing.
Mr. Wang said that the president’s positive test result might become a global reminder of the value of wearing face masks, which are still widely worn in mainland China even though it has not reported a locally transmitted case in more than six weeks.
“He has also had large crowds, shaking hands and greeting people, and he seldom wears a mask,” Mr. Wang said. “He probably serves as a good reminder to the whole world that, as U.S. experts have said, it is important to wear a mask.”
Mark Landler reported from London, and Mike Ives from Hong Kong. Keith Bradsher contributed reporting form Beijing.