The list just keeps getting longer.

Former New Jersey Gov. Chris Christie announced Saturday that he has tested positive for COVID-19, becoming the latest person in President Donald Trump's political orbit to contract the coronavirus as an outbreak spreads through the White House, Trump's campaign and Republican circles.

Hours later, Christie announced that he had checked himself into Morristown Medical Center in New Jersey.

“In consultation with my doctors, I checked myself into Morristown Medical Center this afternoon,” Christie said.

Christie said he was feeling good and experiencing only mild symptoms, but because of his history of asthma, he and his doctors decided hospitalization was an appropriate precaution.

His diagnosis is particularly significant because Christie spent several days in close proximity to Trump while helping the president prepare for Tuesday night's debate against Democratic presidential nominee Joe Biden.

And according to Christie, they weren't wearing masks.

“No One Was Wearing Masks”

Christie participated in Trump's debate-preparation sessions along with several of the president's advisers.

Speaking Friday morning, before announcing his own positive test, Christie described the conditions inside the room.

“No one was wearing masks in the room when we were prepping the president,” Christie said.

The group was small, he said — roughly five or six people.

But several people connected to those preparations have now tested positive.

Trump has COVID-19 and is hospitalized at Walter Reed National Military Medical Center.

Former White House counselor Kellyanne Conway has COVID-19.

Trump campaign manager Bill Stepien has COVID-19.

Top presidential adviser Hope Hicks has COVID-19.

And now Chris Christie has COVID-19.

The coronavirus is no longer something happening somewhere outside Trump's political operation.

It is spreading among the people closest to him.

Another Rose Garden Attendee

Christie was also among the guests at the September 26 White House ceremony announcing Judge Amy Coney Barrett as Trump's nominee to the Supreme Court.

That gathering is now under intense scrutiny.

Approximately 150 people attended the event, where guests sat close together in the Rose Garden and relatively few wore masks.

Christie was there.

So was Trump.

So was Conway.

Republican Sens. Mike Lee of Utah and Thom Tillis of North Carolina attended.

University of Notre Dame President John Jenkins attended.

All have now tested positive for the coronavirus.

It remains unclear whether they contracted the virus at the Barrett ceremony, at associated indoor gatherings or through other interactions.

But the growing number of infected attendees is putting renewed attention on an event where many of the precautions recommended to ordinary Americans were largely absent.

The Virus Moves Through Trump's Circle

The number of positive tests connected to Trump has grown with remarkable speed.

Hope Hicks developed symptoms Wednesday and subsequently tested positive.

Trump and First Lady Melania Trump announced early Friday morning that they had tested positive.

Trump campaign manager Bill Stepien tested positive.

Former White House counselor Kellyanne Conway tested positive.

Republican National Committee Chairwoman Ronna McDaniel tested positive.

Sens. Mike Lee and Thom Tillis tested positive.

Notre Dame President John Jenkins tested positive.

And now Christie has tested positive and entered a hospital.

The outbreak has thrown Trump's White House and reelection campaign into uncertainty only one month before Election Day.

Campaign events have been canceled.

People who recently spent time with the president are being tested.

Officials are attempting to determine who may have been exposed.

And the president himself remains hospitalized.

Months of Resistance to Masks

The outbreak is unfolding after months in which Trump has frequently resisted wearing a mask publicly and has continued holding large gatherings despite warnings from public-health officials.

Just Tuesday night, Trump mocked Biden during the presidential debate for frequently wearing a mask.

“I don't wear masks like him,” Trump said.

“Every time you see him, he's got a mask.”

Trump has repeatedly argued that the country is “rounding the corner” in its fight against the coronavirus.

Yet this week, COVID-19 has moved directly into the president's own circle.

The president is hospitalized.

His campaign manager is infected.

One of his closest aides is infected.

A former senior White House counselor is infected.

Two Republican senators are infected.

And one of the men who sat in a room helping Trump prepare for Tuesday's debate — without masks — is now hospitalized as well.

Christie Takes Precautions

Christie said his hospitalization Saturday was precautionary.

“While I am feeling good and only have mild symptoms, due to my history of asthma we decided this is an important precautionary measure,” he said.

There is no indication Saturday that Christie's condition is severe.

But his hospitalization adds another striking image to an extraordinary week.

Only days ago, Christie was sitting with the president and other advisers preparing for a nationally televised debate.

Today, Trump is at Walter Reed.

Christie is at Morristown Medical Center.

And health officials are trying to determine just how far the coronavirus has spread through the president's political world.

For months, Trump has urged the country to move forward despite the pandemic.

On October 3, the pandemic has moved straight through his front door.