British Prime Minister Boris Johnson has been discharged from the hospital and says he owes his life to the National Health Service staff who treated him for COVID-19, the disease caused by the coronavirus.

"I can't thank them enough," Johnson said earlier in his first public statement since he was moved out of intensive care Thursday night at St. Thomas' Hospital in London. "I owe them my life."

A Downing Street spokesperson said in a statement Johnson will not return to work immediately based on the advice of his medical team and said the prime minister "wishes to thank everybody at St. Thomas' for the brilliant care he received."

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Johnson's partner, Carrie Symonds, said in tweets that she "cannot thank our magnificent NHS enough" and that she "will never, ever be able to repay you and I will never stop thanking you." She admitted there "were times last week that were very dark indeed. My heart goes out to all those in similar situations, worried sick about their loved ones."

Johnson, 55, was diagnosed over two weeks ago, becoming the first world leader confirmed to have the illness. His coronavirus symptoms at first were said to have been mild, including a cough and a fever, and he was working from home during the first few days.

But he was admitted to St. Thomas' on April 5 after his condition worsened and he was transferred the following day to its intensive care unit, where he received oxygen but was not put onto a ventilator. He spent three nights there before moving back to a regular hospital ward.

While he convalesces, Johnson has asked Foreign Secretary Dominic Raab to handle the nation's response to the pandemic that has infected at least 1.78 million worldwide and killed 109,000 people. Experts say those numbers seriously understate the impact of the pandemic, due to limited testing and different ways of counting the dead.

Britain has been in effective lockdown since March 23 and the government is set to extend the restrictions sometime this week.