As Hillary Clinton’s health moves from the fringes to the center of the 2016 presidential campaign, there’s a lot we still don’t know about her scare this weekend.

Here’s what we do know: Clinton was diagnosed with pneumonia on Friday. During a Sept. 11 memorial event on Sunday at Ground Zero, she was unsteady and clearly needed help getting into a van after becoming "overheated and dehydrated." And Clinton canceled a planned to trip to California for Monday while she rests at home.

Hillary Clinton leaves an apartment building Sunday. Andrew Harnik / AP

Clinton’s campaign has been tight-lipped about the Sunday incident, releasing only two short statements throughout the day. Many lingering questions could be easily cleared up by the campaign, while others will take time. Here are nine big questions we still have:

1.) Why hide the pneumonia diagnosis?

Clinton suffered a coughing attack last week during an appearance in Cleveland, which she dismissed as seasonal allergies. She received her pneumonia diagnosis on Friday, but the public was not told about it until hours after the incident at the memorial, raising questions about whether Clinton had any plans to ever inform the public. Between the diagnosis and the near-collapse, Clinton appeared at two fundraisers, ran a national security working session, and held a press conference.

Related: Does Hillary Clinton Have Walking Pneumonia?

Clinton’s campaign appears to have, at best, withheld information from the public and — at worst — misled them by aggressively batting down "conspiracy theories" that her coughing fit was anything more than allergies. Opponents are already seeing the incident as proof of their claims that Clinton has been hiding health issues. And others may now be more incredulous of the campaign’s statements on her health.

2.) Has Clinton been otherwise ill in recent days?

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Has she had pneumonia in the past? Pneumonia is common, but still a potentially dangerous disease that sends about 1 million people to the hospital every year and kills about 50,000, according to the Centers for Disease Control and Prevention.

3.) Who made the call not to go to the hospital and when?

And did Clinton lose consciousness at all? After leaving the memorial, Clinton went to her daughter Chelsea’s apartment and was later examined by her doctor at her own home in Chappaqua, New York. Why was it decided not to visit a hospital immediately?

4.) What is the campaign’s position on the protective press pool?

Presidents and presidential candidates have traditionally traveled with a small, rotating group of journalists so the American public can get real-time updates about unexpected incidents — exactly like the one on Sunday. But Clinton left her press pool behind at the Sept. 11 event and kept them in the dark for 90 minutes before providing any information on her whereabouts or health. Clinton has yet to agree to full "protective pool" coverage, which would allow reporters to follow her door-to-door. Will she now? (Trump, so far, has not allowed for full time "protective" pool coverage, and reporters do not fly on his plane with him to his campaign to events.)

5.) Will Clinton allow a true protective pool if elected president?

Clinton’s health scare is already expected to potentially affect financial markets, but the impact would be far more dramatic if she were president. A 90-minute window with no news about a missing president could lead people to assume the worst. Clinton's, or her campaign's, choice to leave the press pool behind broke with precedent on access—will that change if she's in the White House? Meanwhile, because Clinton has so far not agreed to full coverage, reporters have no way of knowing if she made other stops Sunday.

6.) Does Clinton accept the obligation to inform the public about her health?

Bill Clinton faced questions about his health too, and while he was unforthcoming in 1992, he sat for a detailed interview with the New York Times in 1996. "[T]he public has a right to know the condition of the president's health," Clinton said at the time.

7.) How will this change her schedule going forward?

After canceling plans Monday and Tuesday, Clinton's schedule the rest of week remains up in the air. She is scheduled to appear in Las Vegas on Wednesday and Washington, D.C. Thursday.

8.) Will Clinton’s health affect the first debate?

Clinton’s first debate with Donald Trump is just over two weeks away, on September 26, so she’ll want to be fully recovered by then.

9.) How will voters respond?

Clinton’s core vulnerability is that most Americans don’t find her honest or trustworthy. Will voters now feel like they’ve been misled about her health? Or will the vulnerability of the illness make Americans empathize more with someone who often has difficulty connecting.

To be sure, we know vastly more about Clinton’s health than we do about Donald Trump's. Not only is the information released by her campaign more comprehensive than that released by his, but Clinton has lived her life in the national spotlight for 25 years.

We have intimate details about her 2012 hospitalization, for instance, because she was secretary of state at the time. Trump has not been subjected to the same kind of scrutiny and has been less forthcoming during his presidential campaign.

Clinton may also face a different standard because of her gender, her defenders say. Many presidential candidates have had health issues, but Clinton defenders say that while enduring health issues can be seen as a sign of persistence in male candidates, it’s viewed as a sign of weakness in women.