The superspreader event is thought to be the announcement for the Supreme Court nomination a week ago, although Trump and his advisers have been to several packed public events lately including the first presidential debate.
The First Lady, Trump's campaign manager, a former governor, White House aides, the chairwoman of the Republican National Committee, three US senators and three reporters have since tested positive.
It is a highly unfortunate turn of events for Trump and his family personally and hopefully most people, regardless of politics, would want the US leader to have a full recovery. The coronavirus is something no one should want to catch or want others to get. Symptoms can continue for weeks or months in survivors. The severest forms can damage different organs of the body.
But this year has developed into a timeless morality tale with Trump's mishandling of Covid-19, and the seeming disregard of senior Republicans for people's health, impossible to ignore.
For months, the President has also set an irresponsible tone and example on the virus.
Early on he downplayed the outbreak, saying it would go away, while telling author Bob Woodward it was deadly and airborne. He introduced ineffective travel bans that still allowed thousands of people back into the US from China and Europe.
Testing and PPE were slow to ramp up. Trump pushed unproven medicines. He railed against restrictions and urged reopenings.
He turned mask-wearing into a culture-war issue and set a bad example by avoiding wearing them himself. The Washington Post estimated that Trump was photographed in public wearing a mask only four times from the start of June to the end of September.
He has held indoor and outdoor rallies where thousands of mostly mask-less supporters were nevertheless in close proximity. At the White House, a Republican National Convention event and the Supreme Court announcement featured closely packed crowds and few masks.
The outdoors are safer than enclosed spaces for transmission but are not virus-proof. The amount of time spent near an infected person is important. In the US, where the virus is widespread, measures such as avoiding close contact and large crowds, wearing masks and washing hands need to be followed.
The President getting Covid-19 further pushes the US election campaign and political system onto untrod territory.
There are many questions, including what happens with campaigning, the debates, and the court. Will Democratic nominee Joe Biden and Vice-President Mike Pence continue to test negative for the virus in the coming days?
Mask-wearing has been rare among Trump's family, aides, secret service agents and military staff. At the debate, the Trump entourage walked in wearing masks but then took them off - flouting the rules.
"I don't wear a mask like him," Trump said of Biden in the debate. "Every time you see him, he's got a mask. He could be speaking 200 feet away from him and he shows up with the biggest mask I've ever seen."
On Friday Trump attended a fundraiser in New Jersey even though the White House knew he had been close to someone infected. He also attended events in Minnesota a day earlier.
It adds up to a pattern of Trump behaviour that appears arrogant, reckless and uncaring about the potential for harm to other people and even himself.
