The progression of the disease is usually charted from when a patient starts to manifest symptoms. At first — no matter what the eventual course the infection migt follow — it starts out gently, with symptoms that often include a low fever, cough, fatigue, muscle ache, and nausea. The White House reported today that Trump has “mild symptoms,” and Melania tweeted that she had “mild symptoms but feeling good.” Questions about the severity of the president’s condition were triggered, however, when Trump failed to take part in a call with state governors scheduled for 12:15 p.m. and was replaced without notice by Vice-President Pence.

The White House has announced that President Trump will be hospitalized at Walter Reed Medical Center, suggesting that his condition is on the moderate to severe end of things. It also said that he was given a dose of experimental Regeneron monoclonal antibody therapy, a treatment that has not been approved for use by the FDA. “He may be sicker that they let on,” says John Emy, a physician at New York University Langone Medical Center, while conceding that “he isn’t an average citizen, so they may be acting extremely conservatively.”

What to expect if Trump’s case is mild or moderate

According to CDC guidance, if the disease remains mild or moderate, patients will start to feel better after ten to 14 days, with a cough lasting an average of 19 days. But that does not mean that they will necessarily feel totally back to normal. A New York-area physician who came down with what she considers a moderate case had a fever for 14 straight days. “But it was a full month until I really felt back to normal,” said Peggy E. (who asked that her last name not be used). “A colleague who got sick at the same time still has periodic shortness of breath,” she said.

After patients recover, the CDC recommends that they remain isolated for at least ten days after the appearance of symptoms or three days after recovery — whichever comes later. In the scenario, the odds are small that Trump will be able to meet Joe Biden for their second debate on October 15.

What to expect if Trump’s case is severe

If Trump’s condition instead worsens and the infection rages, the critical turn for the worse would typically come around the end of the first week. The CDC reports that the time from onset of symptoms to acute-respiratory-distress syndrome — the buildup of fluid in the lungs that puts people in the ICU — is usually around eight to 15 days.

Atlas told Fox that Trump “is a very, very healthy guy and the overwhelming majority of people even at his age do fine with this. He is very healthy and so I anticipate the same for him.”

In reality, Trump suffers from three risk factors: In addition to being elderly, he is male and he is obese. While overall only 12.2 percent of people between 65 and 74 who come down with COVID-19 will wind up being hospitalized, men have twice the risk of women. Beyond that, obese people are 113 percent more likely to be hospitalized than those of normal weight.

There is little hospitals can do to cure the disease; drugs like remdesivir only offer a moderate reduction in recovery time. What medicine can do is mitigate the effects of complications like pneumonia, septic shock, heart arrhythmia, and secondary infections as the immune system fights the virus.

Take, for example, British prime minister Boris Johnson, who came down with COVID-19 on March 27. Like Trump, it started with a persistent cough and a fever. Ten days later, Johnson was hospitalized, and two days after that, moved to intensive care. In all, he spent seven nights in the hospital, followed by two weeks recovering at home, not working. If Trump follows a similar trajectory, he will be back on his feet around November 2.

But if his symptoms are severe, he could be in recovery for months. And for every thousand people in their mid-70s or older who get COVID-19, 116 will die.