President Trump officially has his new national security adviser.

A week after announcing the exit of John Bolton, Trump said Wednesday his new national security adviser is Robert O'Brien, who currently serves as U.S. hostage envoy. Trump in July sent O'Brien to Sweden amid rapper A$AP Rocky's assault trial.

Trump last week said he asked for Bolton's the resignation because he "disagreed strongly with many of his suggestions," although Bolton disputed Trump's characterization of his exit and said he offered his resignation. O'Brien, who now replaces Bolton, will be Trump's fourth national security adviser in fewer than three years.

In his tweet announcing the news, Trump said he has "worked long & hard with Robert," although The New York Times' Maggie Haberman reports Trump "didn't really know him" but "liked his portfolio." The Wall Street Journal previously reported that Trump "liked the look of" O'Brien, which the Journal wrote is a "key condition for many Trump appointments."

Trump himself, however, has downplayed the importance of the national security adviser job.

"It's a lot of fun to work with Donald Trump," Trump said last week. "And it's very easy, actually, to work with me. You know why it’s easy? Because I make all the decisions. They don't have to work." Brendan Morrow

An alarming new report by The Wall Street Journal suggests that nearly one in three patients who are infected with COVID-19 receive incorrectly negative test results. "A false negative is problematic because it tells the patient they don't have the virus," Dr. Craig Deligdish explained to the paper.

The estimate about the incorrect results is based on limited data, but the implication that tests may be far from accurate is worrisome. As Deligdish observed, it means that people who've been reassured they are not contagious are likely going forth and spreading the disease to others.

Health care experts additionally told The Wall Street Journal that part of the problem with the tests is how fast they've been approved. "The thing that is different this time is most of these tests are going through a really rapid validation process," said Ohio State University epidemiologist Bill Miller. "As a result, we can't be completely confident in how they will perform." Other doctors have already picked up on the faulty results; in New York City, the center of the U.S. outbreak, "a negative is not clearing anybody who is symptomatic," one emergency room doctor said.

New guidelines to sick Americans asks that if you have coronavirus symptoms, assume you have COVID-19. "Research coming out of China indicates that the false-negative rate may be around 30 percent," writes The New York Times' Harlan M. Krumholz. "Some of my colleagues, experts in laboratory medicine, express concerns the false-negative rate in this country could be even higher."

Curiously, it doesn't seem to go the other way. The Times adds, "the tests appear to be highly specific: If your test comes back positive, it is almost certain you have the infection." Jeva Lange

Elon Musk's ventilator giveaway may do more harm than good.

After weeks of brushing off the COVID-19 pandemic as "dumb," the billionaire Tesla founder earlier this week announced he had 1,000 "FDA-approved ventilators" and ended up donating 40 to New York City's hospital system. Except the devices Musk gave away aren't powerful enough to use in the ICU, and health officials have actually warned against using them on COVID-19 patients because they could spread the virus further.

When Musk purchased and gave to New York's hospitals were Bi-PAP machines made by ResMed, a photo shared by the hospital system reveals. RedMed CEO Mick Farrell later confirmed Musk's purchase of 1,000 5-year-old "bi-level, non-invasive ventilators" known as BiPAPs to CNBC, and said it was "fantastic" that Tesla could transport ResMed's product like it did.

But hospitals are far more desperate for invasive ventilators than BiPAP and CPAP machines, which are usually used to treat sleep apnea — many doctors don't even call them "ventilators," the Los Angeles Times' Russ Mitchell reports. In fact, CPAP machines may have only helped spread COVID-19 through the nursing home outside Seattle that was the epicenter of the U.S.'s initial coronavirus outbreak, NPR reports. These machines can "possibly increase the spread of infectious disease by aerosolizing the virus," NPR writes. Health officials in King County, Washington, have since warned against using CPAP machines on coronavirus patients, as did the American Society of Anesthesiologists back in February.

What would actually help, Farrell added to CNBC, is if Musk's Tesla could produce and donate lithium ion batteries — ResMed can use them to make invasive ventilators that hospitals actually need. Kathryn Krawczyk

Actress Ali Wentworth, ABC News anchor George Stephanopoulos' wife, has tested positive for COVID-19.

Wentworth revealed her diagnosis on Instagram, saying she has "never been sicker" and calling the illness "pure misery." She appeared in a video message on Good Morning America on Thursday, describing feeling "very winded" before she tested positive and experiencing tightness in her chest, as well as a fever.

"It feels like a really, really horrible flu," she explained, saying some of the things that have helped have been Tylenol, chicken soup, and hot baths.

Stephanopoulos on GMA said Wentworth was "doing ok" early this morning and that her fever was slightly down last night, although the symptoms have been going "in cycles" for her. Stephanopoulos also said he personally doesn't have symptoms and is "definitely being careful" while taking care of Wentworth, although he speculated about the potential that he, and many other New Yorkers, could have already contracted the coronavirus.

"At this point, it's just so hard to know," Stephanopoulos said. "So many of us in New York City are already presumed to have had it. Right now, I have no symptoms. ... But, you know, I wonder myself whether I already had maybe a mild version and just didn't even know it. There's no way to know right now." Brendan Morrow

Filipino President Rodrigo Duterte has ordered the police and military to "shoot dead" any "troublemakers" who cause disturbances during the coronavirus quarantine in the Philippines, The Philippine Star reports. The move comes after protestors staged demonstrations over the lack of food and financial aid they've received from the government since the lockdown began in the country on March 17.

"I will not hesitate [to tell] my soldiers to shoot you. I will not hesitate to order the police to arrest and detain you," said Duterte in his address, adding: "Instead of causing trouble, I'll send you to the grave." The president is infamous for his alleged violations of human rights, previously drawing the fury of the international community over his order for vigilante hit squads to murder suspected drug dealers without due process.

Amnesty International condemned Duterte's new statements. "The abusive methods used to punish those accused of breaching quarantine and the vast number of mass arrests that have been carried out to date, against mainly poor people, are further examples of the oppressive approach the government takes against those struggling with basic needs," said the organization's local section director, Butch Olano.

The human rights NGO added that more than 17,000 people have already been arrested for violations of the lockdown and curfew in the Philippines, and that "reports have also appeared of inhumane punishments those breaching quarantine have been made to endure, including sitting for hours in the hot sun or being detained in dog cages." Jeva Lange

The Secret Service signed an "emergency order" this week to rent $45,000-worth of golf carts in the town of Sterling, Virginia, where President Trump has a golf course, The Washington Post reports. The 30-cart fleet, which the Secret Service is renting through the end of September, was described as being necessary in order to protect a "dignitary," although the president was not explicitly referenced by name.

Surprisingly, while many nonessential businesses around the country have closed to prevent the spread of disease, Virginia's Trump National Golf Club remains open. Gov. Ralph Northam (D) allowed for golf courses to continue to operate so long as golfers keep a six-foot distance from others. The Virginia club is a favorite of the president's; he has visited it 76 times since taking office, most recently in October.

The Post notes that Trump has not played golf since March 8, when there were still only about 500 confirmed COVID-19 cases in the U.S. and 21 deaths, most of which were concentrated at a nursing home in Washington State. In a statement, Secret Service spokesperson Cathy Milhoan clarified that the "emergency" contract referred specifically to "a need for expedited handling of the procurement due to deadlines within the agency's business processes." Read more at The Washington Post. Jeva Lange

A day after New York Gov. Andrew Cuomo (D) projected that 16,000 New Yorkers could die of the novel coronavirus by the time the outbreak has run its course, President Trump told the state to "stop complaining."

"New York has gotten far more than any other state, including hospitals and a hospital ship, but no matter what, always complaining," the president said in a tweet addressing criticisms from Sen. Chuck Schumer (D-N.Y.). "It wouldn't matter if you got ten times what was needed, it would never be good enough. Unlike other states, New York unfortunately got off to a late start. You should have pushed harder. Stop complaining and find out where all of these supplies are going."

New York is the center of the U.S. coronavirus outbreak, with over 83,800 cases and nearly 2,000 deaths as of Thursday morning; the next highest statewide death toll, in New Jersey, is just 355 cases. Many leaders in New York have pleaded for relief for the city's overburdened hospitals, with Mayor Bill de Blasio saying Wednesday that the city needs 3.3 million N95 masks, 2.1 million surgical masks, 100,0000 isolation gowns, and 400 ventilators by Sunday to keep up with the exploding demand.

Trump's tweets apparently came in response to a tweet from Schumer, in which the senator echoed local concerns: "President Trump needs to harness industry to quickly produce more medical supplies and equipment under the Defense Production Act NOW," he'd tweeted. "He needs to appoint a czar like a military or logistics expert to lead the effort to make and get the supplies where they're needed." Jeva Lange