Regeneron Pharmaceuticals corporate headquarters.

The White House in Washington DC on October 2nd. Saul Loeb / AFP / Getty Images

With President Donald Trump’s hospitalization for Covid-19, more and more cases are appearing in the White House and in its close circles.

Here’s what you need to know:

Who was infected: Trump, First Lady Melania Trump, top advisor Hope Hicks, former White House advisor Kellyanne Conway, Trump campaign manager Bill Stepien and Republican Sens. Thom Tillis and Mike Lee all tested positive.

The timeline: Hicks first felt symptoms on Wednesday night and tested positive on Thursday morning. Trump was tested Thursday evening and announced his results early Friday morning. Tillis, Lee, Stepien and Conway announced their results on Friday. On Friday afternoon, Trump was hospitalized in Walter Reed.

Trump’s treatment: According to Trump’s doctor, the president received the Regeneron antibody cocktail, an experimental drug that has not yet been approved by the Food and Drug Administration. He’s also been given the antiviral drug Remdesivir, which is FDA approved for emergency use, and has been shown to reduce the recovery time of some coronavirus patients.

Trump also takes zinc, vitamin D, famotidine, melatonin, and a daily aspirin.

Questions that arise: As the White House scrambles to respond to the cluster, experts and doctors are also raising questions about the timing of Trump’s infection and how we got here in the first place.

If he was tested every day, how could no one tell that Trump had been exposed earlier? If officials knew of Hick’s diagnosis by Thursday morning, why wasn’t Trump tested that night? And what exactly is Trump’s condition given that the White House has published mixed messages – first saying that he was energetic and stayed in the White House, then later that day saying that he was tired and went to the hospital?

“These are critical questions that need to be answered – that should have been answered,” said Don Lemon of CNN on Friday evening.