Two employees of one Walmart store in the Chicago area have died after contracting the coronavirus. The company did not specify the timing of their illnesses, but said the store remains open after passing "necessary inspections," last week.

Updated at 9:12 p.m. ET

President Trump doubled down Sunday on the suggestion that people facing the coronavirus should consider taking an anti-malaria drug that has not been proven to be an effective treatment.

The Pentagon was aware of the likelihood of a pandemic brought on by a novel coronavirus years ago, predicting with startling accuracy shortages of masks, hospital beds and ventilators that could occur in an outbreak, according to a 2017 internal document reported by The Nation.

British Prime Minister Boris Johnson, who was diagnosed with the coronavirus last month, has been admitted to the hospital for testing on the advice of his doctor, his office said Sunday.

"This is a precautionary step, as the Prime Minister continues to have persistent symptoms of coronavirus 10 days after testing positive for the virus," a spokesperson said in a statement.

Johnson announced on March 27 that he had tested positive. He said at the time that he had "mild symptoms" of COVID-19, including a fever and "a persistent cough."