U.K. Prime Minister Boris Johnson is in intensive care in a London hospital with COVID-19, officials said on Monday, one day after Johnson was admitted to the hospital with persistent symptoms of the coronavirus. Johnson was the first world leader to test positive for the coronavirus on March 27. “Over the course of this afternoon, the condition of the prime minister has worsened and, on the advice of his medical team, he has been moved to the intensive care unit at the hospital,” a spokesperson said. The Prime Minister is reportedly conscious and the decision was taken as a precaution in case he needs ventilation. Officials had earlier said Johnson was only taken to hospital as a “precautionary step” on Sunday, and would continue to lead the British government. He has nominated Foreign Secretary Dominic Raab to deputize for him “where necessary,” a spokesperson said. “Last night, on the advice of my doctor, I went into hospital for some routine tests as I’m still experiencing coronavirus symptoms,” Johnson tweeted from the hospital earlier on Monday, before being admitted to intensive care. “I’m in good spirits and keeping in touch with my team, as we work together to fight this virus and keep everyone safe.” Johnson is not the only top British government official to be infected with COVID-19. His Health Secretary, Matt Hancock, also has the disease, along with his top advisor Dominic Cummings. His Chief Medical Officer, Chris Whitty, recently returned to work after self-isolating with symptoms of the disease. And Johnson’s pregnant fiancée, Carrie Symonds, said she has been suffering with symptoms of COVID-19 for the past week.