The UK remains in the “containment” phase of tracing coronavirus cases to prevent it spreading in the community, England’s deputy chief medical officer has said.
Jennie Harries told the BBC a decision about the next phase of delaying the spread of the virus would depend on how fast the number of cases rose.
But she said the UK was “teetering on the edge” of sustained transmission.
Measures to slow the virus needed to be “proportionate”, she said.
And Dr Harries warned the public against panic-buying, saying it was unnecessary and it could “engender panic in itself”.
The number of confirmed cases of Covid-19, the illness caused by the virus, rose to 164 in the UK on Friday, with 20,338 people tested.
The UK’s strategy on responding to the virus has four phases: containment, delay, mitigation and – running alongside these – research.
Up until now, the containment phase has involved catching cases early and tracing all close contacts to halt the spread of the disease for as long as possible,
Moving into the delay phase could see the introduction of “social distancing” measures, such as closing schools and urging people to work from home.
Dr Harries said that the “junction” between containment and delay is “when we can see inevitably that we are moving from a few cases across the population to sustained community transition”.
“We are, if you like teetering on the edge, but not there just yet,” she said. “We have surveillance systems in place and we’re watching that on a daily basis.”
Dr Harries said a decision on formally moving to the next phase would depend on how quickly the number of cases rises.
The delay phase would focus on trying to prevent cases from rising too sharply, pushing the peak of the epidemic out of the winter period and helping health and social care services manage the flow of patients, she said.
Scientific advisers are due to review the evidence next week on measures such as restricting large gatherings, she said.
But Dr Harries said they needed to “balance the benefits” with minimising disruption to people’s lives and the economy, as well as ensuring that they are implemented at the time when they will have the most impact.
More than 140 British nationals are on board a cruise ship which was barred from docking in San Francisco, California, after an outbreak of the virus.
US Vice President Mike Pence said the Grand Princess – sister ship of the Diamond Princess, which was the site of a major outbreak in Japan – would be sent to a non-commercial dock where all 3,533 passengers and crew would be tested.
Dr Harries said she has a “great deal of trust” in the US public health system and said the Foreign Office was “extremely active” in looking after UK citizens abroad.
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