More than 200 people, including several MPs, have been contacted by health officials over fears they could have been exposed to the coronavirus at a conference in central London.

Public Health England (PHE) wrote to those who were at the UK Bus Summit at the QEII Centre in Westminster on 6 February after it emerged one of the delegates had tested positive.

“One of our main priorities has been to identify any people who we think have been in close contact with confirmed cases of Covid-19 to provide public health advice, as they may be at slightly increased risk of catching the virus,” said Dr Yimmy Chow, a consultant in health protection at PHE.

“While the degree of contact conference delegates may have had with the case is unlikely to have been significant, we have taken a precautionary approach and informed them of the situation.”

Two of the MPs who attended the conference said they have decided to stay at home after health officials advised people who may be suffering to self-isolate.

Lilian Greenwood and Alex Sobel, the Labour MPs for Nottingham South and Leeds North West, both said they were feeling well but had decided to cancel appointments, in line with health officials’ advice.

The Transport Times bus summit is an annual event, but one that attracted more enthusiastic delegates this year to the heart of Westminster after major political parties raised buses up their agenda. Before and during the day-long conference, about 250 delegates mingled over refreshments among exhibits in the small adjoining Cambridge Room.

As well as transport minister Lady Vere and senior civil servants, delegates came from across the UK, including from Transport Scotland, Transport for London, major bus and rail operators, manufacturers, councils and thinktanks. A sizeable delegation came from Lagos and there were representatives from Heathrow airport and MacMillan Cancer Support, whose service users are most at risk from the virus.

The news comes amid growing concerns about the spread of the virus within the UK. As of Friday, a total of 2,964 people have been tested in the country, of which 2,955 were confirmed negative and nine positive. In China, where the virus originated, the number of deaths from coronavirus has reached 1,523, with more than 66,000 recorded infections, in figures announced early on Friday morning.

It also emerged on Friday that a Channel 4 employee was among those being tested for coronavirus after feeling unwell following a trip to Asia. A Channel 4 spokesman said: “As a precautionary measure, they decided to seek medical advice and, in line with the latest public health advice regarding the coronavirus, they were taken to hospital for a precautionary test.”

Later the same evening, Facebook said it was cancelling its global marketing summit, which was due to take place in San Francisco next month, because of coronavirus concerns.

As many as eight flights at Heathrow airport were said to have been caught up in delays or checks as a result of government health officials responding to coronavirus-related concerns over passengers feeling unwell.

United Airlines confirmed that staff in London had been providing assistance to a flight from San Francisco which had landed at Heathrow following reports of an individual becoming unwell onboard.

A man who had been on the flight said a passenger had been taken to the back of the plane ahead of the arrival of health officials before passengers were allowed to disembark after half an hour.

“There was an initial announcement that someone had taken ill and would be taken off,” said Andy West, a public relations executive at Hotwire, said.

“Shortly afterwards he said that there was a suspected case of coronavirus and that the passenger had been isolated at the back of the plane.”

West said the pilot had said that there were seven other planes at Heathrow experiencing similar issues, including a number in front of it on the tarmac which were due to be visited. After disembarking, passengers were asked to complete a form and were questioned about their recent travel history and symptoms.

“There was no sharp intake of breath when the pilot made the second announcement but I think that a lot of people, including myself, were a bit anxious and probably worried. I really hope the person doesn’t have it and that if we don’t hear anything then no news will be good news,” he said.

The United Airlines flight which was affected was United flight 901, according to the US airline.

Heathrow airport, which was unable to say how many flights had been affected, said that the airport was operating as normal. It added that PHE were managing Coronavirus-related issues on the ground, which may require some aircrafts to be slightly held up when disembarking.

A Heathrow spokesperson said: “We are working closely with Public Health England officials to facilitate their access to the airport so that they can implement their enhanced monitoring measures as a precaution.

“In line with the latest Public Health England advice, we are encouraging passengers and colleagues to maintain good hand hygiene and report any suspected symptoms to NHS 111.”

Q&A How can I protect myself and others from the coronavirus outbreak? Show The World Health Organization is recommending that people take simple precautions to reduce exposure to and transmission of the coronavirus, for which there is no specific cure or vaccine. The UN agency advises people to: Frequently wash their hands with an alcohol-based hand rub or warm water and soap

Cover their mouth and nose with a flexed elbow or tissue when sneezing or coughing

Avoid close contact with anyone who has a fever or cough

Seek early medical help if they have a fever, cough and difficulty breathing, and share their travel history with healthcare providers

Advice about face masks varies. Wearing them while out and about may offer some protection against both spreading and catching the virus via coughs and sneezes, but it is not a cast-iron guarantee of protection Many countries are now enforcing or recommending curfews or lockdowns. Check with your local authorities for up-to-date information about the situation in your area. In the UK, NHS advice is that anyone with symptoms should stay at home for at least 7 days. If you live with other people, they should stay at home for at least 14 days, to avoid spreading the infection outside the home.

PHE said it was not commenting on individual situations and activities at airports but added that it was carrying out “enhanced monitoring” of direct flights from China, Thailand, Japan, South Korea, Hong Kong, Taiwan, Singapore, Malaysia and Macau. This is in addition to the usual public health response to someone becoming unwell on a plane from any destination.

Enhanced monitoring includes early warning by a pilot of any passenger illness as soon as possible and formal assurance by the captain on the health of passengers prior to disembarkation.

Virgin Atlantic said it had not been affected by the reports at Heathrow on Friday. British Airways, the airline with the largest number of flights using the airport, was also approached for comment.