Is Trump contagious? How is Chris Christie? We're answering your questions about the president and COVID-19

Less than a week after President Donald Trump announced that he and the first lady had tested positive for COVID-19, Trump claimed Thursday that he was "not contagious at all."

While the duration of infectiousness for COVID-19 has yet to be confirmed, scientists believe that people with mild to moderate COVID-19 may shed the virus for up to 10 days after symptoms first appear, according to the Centers for Disease Control and Prevention.

The president announced on Twitter early Friday that he and first lady Melania Trump had tested positive for the coronavirus. Trump spent three days at Walter Reed National Military Medical Center, where he was treated for COVID-19. He returned to the White House on Monday and reentered the Oval Office on Wednesday.

What do you want to know about Trump's coronavirus diagnosis? Submit your questions via this form and we will continue to answer your questions here.

How is Chris Christie?

– Jennifer from Davis, California

The former New Jersey governor and Trump adviser entered Morristown Medical Center on Oct. 3 after testing positive for the virus; he was still there on Oct. 8. When he checked himself in, he said he had mild symptoms. NJ.com reported that Christie and his doctors have been publicly silent about his treatment and condition.

Christie initially reported his hospitalization, writing on Twitter: "In consultation with my doctors, I checked myself into Morristown Medical Center this afternoon. While I am feeling good and only have mild symptoms, due to my history of asthma we decided this is an important precautionary measure."

There is no evidence supporting some claims circulating online that Christie is on a ventilator.

Is Trump contagious at this point?

– Geoff from Cross Plains, Wisconsin

Trump told Fox Business' Maria Bartiromo on a call Thursday morning that "I don’t think I’m contagious at all."

The CDC recommends that people who have had COVID-19 can be around other people again if they meet three criteria: It has been 10 days since symptoms first appeared and at least 24 hours with no fever without the use of fever-reducing medications, and other symptoms are improving.

Trump — who appeared to have a relatively severe case of COVID-19, requiring supplemental oxygen and taking intravenous drugs — may even need to quarantine for longer, as the CDC says that patients with severe cases "likely remain infectious no longer than 20 days after symptom onset."

The virus comes on quickly, and it is most infectious during the day or two before symptoms appear as well as a day or two after someone feels sick, if they ever do. Most people don't test positive in the first day or two after exposure.

Dr. Ashish Jha, Dean of the Brown University School of Public Health, said on Twitter Thursday that because Trump was treated with steroids early on in his disease course, he could be infections for longer than two weeks.

"Steroids likely extend shedding of SARS-CoV2," Jha said. "We saw this with MERS (another coronavirus) and have some evidence with COVID."

An August study in the journal Frontiers in Pharmacology found that steroid use may be accompanied by increased use of antibiotics, longer hospitalization and prolonged viral shedding.

Is Trump isolating himself?

– David from Arcata, California

Trump, confined to the White House residence since returning home from the hospital, spent Wednesday afternoon in the Oval Office and taped a video near it, even as the West Wing has become a hot zone for the virus.

"I'm standing in front of the Oval Office at the White House, which is always an exciting place to be," Trump said in the video he tweeted out in the late afternoon.

Doctors had wanted Trump to stay in the White House residence.

The White House said in a statement Tuesday that residence staff in direct contact with the first family are tested daily, with support staff tested every 48 hours. The residence has hired independent health consultants to check on staff and their families. Staff wear full PPE and "continue to take all necessary precautions, which include updated procedures to protect against cross contamination," the White House said.

Meanwhile, the Trump campaign is exploring the prospect of an event on Monday in Pittsburgh, an aide told USA TODAY. The aide did not elaborate, saying only it would be an "event" and not a "rally" for the COVID-stricken president.

Will the drugs used to treat Trump's COVID be available to the rest of the nation?

– Bob from San Antonio, Texas

Trump's doctors said the president continues to take the steroid dexamethasone and he completed a five-day course of the antiviral drug remdesivir on Tuesday. He has also taken zinc, vitamin D, famotidine, melatonin and a daily aspirin, doctors said.

Trump's therapies have been similar to those available to most other hospitalized COVID-19 patients – with two major exceptions. The president received a dose of an experimental drug only tried so far in about 2,000 people as part of a research trial, and he's gotten everything far sooner than would a typical COVID-19 patient.

Soon after arriving at the hospital Friday evening, Trump was given the first of five doses of remdesivir. The drug, made by Gilead Sciences of California, was developed to treat Ebola but has been repurposed to use against COVID-19.

Less than 48 hours after his first symptoms, he had already received a dose of a monoclonal antibody made by Regeneron, a New York biotech company. The drug, REGN-COV2, is intended to mimic the natural process of the immune system, providing it with molecules called antibodies the body normally manufactures to fight off specific diseases.

Trump was able to get it under a "compassionate use" exemption, which the company said it has granted to fewer than 10 people so far, after requests from their doctors and approval by the U.S. Food and Drug Administration, a process that typically takes days to weeks.

The company estimates between 70,000 and 300,000 treatment doses will be available under an agreement with the U.S. government, which would provide the treatment for free to COVID-19 patients.

Trump released a nearly five-minute video Wednesday evening on Twitter to update supporters on his condition and said the antibody cocktail was "key" to his recovery.

The president said his administration was working to make the drug free for Americans: "I want everybody to be given the same treatment as your president, because I feel great. I feel like perfect," Trump said. "I want to get for you what I got and I'm going to make it free. You're not going to pay for it."

How expensive is each remdesivir treatment Trump receives?

— Geri from Horse Cave, Kentucky

For remdesivir, private insurance companies will pay $520 per vial or $3,120 for a five-day course of treatment, while the company will charge the U.S. government $390 per vial, or $2,340 per patient.

As for REGN-COV2, prices aren't set for drugs until they're approved by the FDA. But monoclonal antibodies are usually extremely expensive. Cancer-related monoclonal antibodies often cost nearly $100,000 a year, according to one 2018 study. For COVID-19, monoclonal antibodies are expected to be orders of magnitude cheaper, likely on the order of a few thousand dollars for a single-dose regimen.

Trump previously reported he earned capital gains from Regeneron Pharmaceuticals and Gilead Sciences Inc., both manufacturers of two medicines he's taken as part of his COVID-19 treatment.

Does Trump have a fever?

– Grace from New Haven, Connecticut

Conley said in a memo Wednesday that Trump had been fever-free for more than four days, symptom-free for over 24 hours, and had not needed nor received any supplemental oxygen since initial hospitalization.

Trump described catching the virus as a "blessing from God" in a video message Wednesday.

"I think this was a blessing from God that I caught it," he said, adding that it was a "blessing in disguise" so he could understand firsthand the benefits of Regeneron's experimental drug cocktail.

How many people were infected during the nomination event for Judge Amy Coney Barrett?

– Satish from Elk Grove, California

Trump and at least 11 other people who attended a White House ceremony unveiling Amy Coney Barrett's nomination to the Supreme Court have been infected, including two Republican members of the Judiciary Committee.

Though the activity was held outside at the Rose Garden, the majority of the 180-plus people in attendance sat close to each other for an extended period, and most people didn’t wear masks. There were smaller indoor gatherings as part of the occasion. That combination may have resulted in a super spreader event, the type that leads to a cluster of infections.

Help us ID them all: Here's everyone at the White House Rose Garden event

Others at the ceremony who tested positive for the virus include first lady Melania Trump; former White House counselor Kellyanne Conway; Kayleigh McEnany, White House press secretary; Trump adviser and former governor of New Jersey, Chris Christie; GOP Sens. Mike Lee of Utah and Thom Tillis of North Carolina; President of Notre Dame University John Jenkins; Pastor Greg Laurie, pastor of the Harvest Christian Fellowship; Karoline Leavitt and Chad Gilmartin, White House press staff; and a reporter covering the announcement.

How many in this administration have tested positive for COVID-19?

– Leah from Island City, Oregon

At least 26 administration officials, associates and other contacts have tested positive. See the full list here.

Most of the nation's top military leaders are quarantining after coming in contact with a senior officer with COVID-19. And the head of the White House security office is gravely ill with COVID-19 and has been hospitalized since September.

Several administration officials have tested positive before, including National Security Adviser Robert O'Brien, Vice President Mike Pence press secretary Katie Miller, and one of the president's personal valets.

When did the president begin to feel ill?

– Linda from New York City

It’s still unclear what day the president first began experiencing symptoms as mixed messaging from the White House continues to muddle the timeline. Trump first announced his diagnosis on Twitter early Friday morning but made no mention of symptoms.

Conley said in a press briefing Saturday morning that Trump experienced a mild cough, nasal congestion and fatigue from COVID-19 on Thursday.

A visual guide: The timeline of President Donald Trump's COVID-19 treatment

What is First Lady Melania Trump's present condition?

– Danny from Savannah, Georgia

The first lady has been isolating at the White House after testing positive for the coronavirus. She did not leave the White House to visit the president in the hospital.

She's not saying anything on Twitter but her chief of staff says the first lady is good.

"She continues to feel well," Stephanie Grisham, told USA TODAY on Wednesday.

Grisham is also isolating because much of the White House staff, including all of the East Wing staff, are working from home for the time being.

Conley on Saturday said that the first lady "has no indication for hospitalization, advanced therapy."

How is their son, Barron Trump, doing?

– Monica from Thousand Oaks, California

Grisham told USA TODAY over the weekend that Barron, 14, had tested negative, and "all precautions are being taken to ensure he’s kept safe and healthy."

It was not clear if Barron was in the White House with his mother.

Is there any news regarding Hope Hicks' condition?

– Julia from Manassas, Virginia

It's unclear how Hope Hicks is faring. Trump announced on Twitter late Thursday that the longtime aide had tested positive for the coronavirus.

White House chief of staff Mark Meadows said the White House learned of Hicks' positive test as Marine One was lifting off the South Lawn on Thursday to take the president to a fundraiser in New Jersey. Questions later surfaced about why Trump attended the campaign event knowing he had been exposed to someone with a positive test result.

Trump went ahead with campaign events in: After Hope Hicks tested positive

Hicks is frequently in contact with the president and was with Trump as he traveled to and from the first presidential debate in Cleveland on Tuesday. She appears in a photo deplaning in Cleveland, not wearing a protective face mask. Hicks also traveled aboard Marine One, the presidential helicopter, for a Minnesota rally Wednesday.

New Jersey Gov. Phil Murphy blasted Trump as "reckless" on Monday for coming to the state last week even though Hicks had been diagnosed with COVID-19. He said his administration is investigating whether the Thursday fundraising event at Trump's golf club in Bedminster violated the governor's executive orders by exceeding capacity limits and providing a buffet meal to the 206 attendees.

When was Trump's last confirmed negative COVID-19 test?

– Lisa from Safety Harbor, Florida

It is unclear if Trump was tested prior to last Tuesday's presidential debate. Trump arrived at the debate venue late, and, according to Fox News anchor Chris Wallace, who moderated the debate on Sept. 29 in Ohio, the timing of Trump's arrival meant that there was insufficient time for Trump to get tested and receive a result.

A coronavirus test made by Abbott, a U.S. health care company, can deliver results in as little as 15 minutes. However, the test may return a high rate of false negatives. The White House did not return a request for comment on Wallace's allegation.

"I'm not going to get into all the testing going back, but he and all the staff routinely are tested," Conley said Saturday.

During a press briefing in May, Trump said he had been receiving "on average a test every two days, three days." Earlier that same day, White House Press Secretary Kayleigh McEnany, who announced Monday that she also had tested positive for the coronavirus, said Trump was tested "multiple times a day."

How much do Trump's existing risk factors impact his ability to fully recover?

– Jana from Salt Lake City, Utah

Trump has several risk factors that put him on the more worrisome end of the spectrum. His age, weight and gender all add to his vulnerability.

Trump turned 74 in June, putting him at five-times higher risk of hospitalization and 90-times higher risk of death than someone in their 20s, according to the CDC. Just a year older, and he'd be at eight-times higher risk of hospitalization and 220-times higher risk of death.

The president's weight-to-height ratio bumps him just over the boundaries of what's considered obese, putting him at three-times higher risk of a serious infection compared to someone at a healthier weight, according to the CDC.

Being male also puts Trump at higher risk. Just over 54% of Americans who have died of COVID-19 have been male, while 46% have been female; in Trump's age group, 61% of the deaths have been among men.

Contributing: Karen Weintraub, Elinor Aspegren, Jeanine Santucci, David Jackson, Jorge L. Ortiz, Savannah Behrmann and Maria Puente, USA TODAY

This article originally appeared on USA TODAY: Trump, COVID questions: Is he contagious? How is Chris Christie?