WASHINGTON (BLOOMBERG) - US President Donald Trump is 74 years old and overweight, putting him in a higher-risk category of Covid-19 patients and thrusting his health into the spotlight just a month before the US election.
The positive diagnosis for the world's most powerful man and First Lady Melania Trump threw a new wrench into the gears of a chaotic campaign that many see as a referendum on his handling of the virus.
Mr Trump's age, weight and gender all make him more susceptible to complications than his wife, who's 24 years younger. Even at his age, a majority of patients experience only mild or moderate symptoms, but researchers are still baffled as to why some go on to become seriously ill.
"Covid's like playing Russian roulette," said Associate Professor Brian Oliver, an expert in respiratory diseases at the University of Technology Sydney.
"It can affect anyone really badly, but we know that when people are older and when they've got more pre-existing co-morbidities, the chances of being affected and having a more severe reaction are much worse."
It's not clear whether the President has any symptoms. The First Lady said in a tweet that she and her husband "are feeling good".
Although Mr Trump has been dismissive of preventive measures such as mask-wearing, increasing the possibility of further transmission in Washington, he and the First Lady plan to remain at the White House "during their convalescence", the President's physician said.
People between ages 65 and 74 are five times more likely to be hospitalised and 90 times more likely to die than those 18 to 29, according to the Centres for Disease Control and Prevention. Men have accounted for 54 per cent of Covid-19 deaths in the United States, according to the CDC.
Mr Trump's body-mass index, a measure based on height and weight that doctors use to measure body fat, also creates potential hazards. At the time of his annual physical exam in June, the President stood at 1.9m tall and weighed 111kg, giving him a BMI of 30.5. A figure of 30 or greater is considered obese.
Though experts caution that the relationship between obesity and Covid mortality isn't well understood, one meta-analysis of global data published in August suggested that obese people were 48 per cent more likely to die from Covid-19, compared with people with BMIs in the normal range. Among nearly 17,000 patients hospitalised for coronavirus in the US, more than three-quarters were obese, according to a separate study.
"Men are more at risk, unhealthy men are more at risk and it's not necessarily just the obesity, but the other factors that go along with the obesity, particularly the cardiovascular disease and diabetes," said Professor Gary Wittert, a professor of medicine and director of the Freemasons Foundation Centre for Men's Health at Adelaide University.
Mr Trump will, of course, have access to top-flight medical monitoring and care, and with an annual salary that puts him in the top tier of Americans, he belongs to a demographic group that's fared relatively well during the pandemic.
The President also doesn't drink or smoke, which should improve his general health. Risk of serious illness or death grows sharply in older patients with pre-existing conditions such as heart disease or cancer.
Other world leaders who have caught the virus have had differing experiences. Brazilian President Jair Bolsonaro, 65, had only a mild illness in the summer.
British Prime Minister Boris Johnson, 56, became seriously ill and required treatment in intensive care after testing positive in March. Mr Johnson was taken to the hospital after failing to shake off a cough and fever he had experienced for 10 days and was put into intensive care the following day.
Mr Johnson spent about a month away from his duties at the peak of Britain's outbreak. Following reports of concern among his Conservative Party colleagues that he has still not fully recovered, the prime minister said this week that he is fitter than a "butcher's dog".
The US has reported about 7.3 million Covid cases, with roughly 208,000 deaths, the most of any country.
The World Health Organisation's technical lead on Covid-19, Dr Maria Van Kerkhove, has said a number of studies put the fatality rate of the disease at 0.6 per cent, though with a wide variance for age.
Treatment options are better now than they were last spring, when hospitals across Europe and the US were flooded with Covid patients. A few therapies such as the anti-inflammatory dexamethasone and the antiviral remdesivir have been shown to benefit patients, and doctors have a better sense of when to use ventilators - or when to use less invasive breathing assistance.