Health officials have contacted hundreds of conference attendees in London, after it emerged one of them was later diagnosed with coronavirus. The person, who has not been identified, was at the UK Bus Summit at the QEII Conference Centre last week.Two Labour MPs who were also at the conference said they were well but cancelling public engagements until 20 February as a precaution. So far, nine people in the UK have tested positive for the virus. MP Lilian Greenwood – a former chair of the transport select committee – spoke at the 6 February conference in Westminster, which was attended by about 250 people from the bus and transport industry. She said on Twitter she was “feeling completely well” but to be “extra-cautious” she was cancelling her public engagements for two weeks from the date of the conference, in line with advice from Public Health England (PHE). Her colleague Alex Sobel, MP for Leeds North West, told BBC News he only found out through a journalist about the positive test and was “concerned” other attendees may still be unaware.Mr Sobel, who said he was not exhibiting any symptoms, called the NHS non-emergency 111 phone line to be “formally assessed” and has been “established as low risk”. He said he spent Friday afternoon in a room in his office away from staff but, after receiving the advice from 111, will not remain in isolation – although he has cancelled public engagements as a precaution. The government’s buses minister Baroness Vere – who was a keynote speaker at the conference – is “following Public Health England advice”, the Department for Transport said. Transport Times, the organiser of the conference, sent an email on Thursday afternoon to attendees informing them that a person confirmed to have coronavirus – which causes an illness now named Covid-19 – had been at the event. The email included advice from PHE urging delegates that no action was needed if they felt well, but if they developed symptoms such as a fever or cough they should stay indoors, avoid contact with others and call NHS 111. The letter told people to follow the advice until 20 February, “even if your symptoms are minor.”