BOSTON (CBS) – President Donald Trump said early Friday morning that he has tested positive for coronavirus. The president has cleared his schedule, but it’s not clear yet how long he will quarantine.

WBZ-TV’s Dr. Mallika Marshall said the president will be watched closely for symptoms while he’s in quarantine.

Why is the president considered at higher risk?

President Trump is 74 years old. He’s overweight. We don’t know if he has other underlying risk factors because we don’t necessarily know as much about the health status of this president as we have with prior presidents. But, we know that he has at least two risk factors that put him at high risk.

Once someone tests positive how long are they considered contagious and how long should he quarantine?

If he develops symptoms certainly, for as long as he has symptoms. If he doesn’t develop symptoms, then we assume that someone could be contagious up until about 14 days, hence the 14-day isolation period.

How long does it typically take to start showing symptoms?

We have a general idea that usually when you’ve become exposed, if you’re going to develop symptoms, you usually do it between two and 14 days after exposure. But the average time to symptom onset is about five days. So depending on when he was exposed we’ll have a better sense as to whether he’s going to develop symptoms or not.

When is it safe to say someone infected is out of the woods in terms of their health?

If someone doesn’t develop symptoms then we generally say after about two weeks, then they’re probably not contagious and they probably aren’t going to develop symptoms. If someone develops symptoms then only time will tell. A lot of people develop symptoms and they’re chugging along and they’re doing just fine and then all of a sudden precipitously they get sicker.

I do have to say that the odds are in his favor, despite the risk factors that we know about, chances are he’ll recover.

The next debate is in less than two weeks, what would you need to make you feel comfortable with President Trump participating?

If he has symptoms, for sure the debate should not be held in person. If he doesn’t develop symptoms, I still think there’s a question mark there. So I think the certainty of the debate is definitely in question.

Dr. Mallika Marshall