A worst case scenario could see coronavirus wipe billions off the local economy, a retail analyst has warned.
The stark warning from a Norwich analyst came as the government predicted up to a fifth of all UK workers could be off sick if the virus peaks.
Local employers said they were remaining calm with contingency plans in place to cope.
And bosses of firms involving large public venues, such as Norwich's Castle Quarter and Banham Zoo, said they would only close when the government instructed them to do so.
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As the number of people infected in Britain rose again, the potential economic impact was being assessed.
Professor Joshua Bamfield, director of the Centre For Retail Research in Norwich, said the centre had conducted a recent analysis which showed what the effect of coronavirus could be on Norfolk business.
In the worst case scenario, he said the virus could wipe off up to "10pc to 15pc" from the local economy which would equate to billions.
According to 2017 figures from Norfolk County Council, the latest available, it would work out as roughly £2.7bn.
"If coronavirus escalates it could cause a mild recession which could still be very painful," he said. "If people are really frightened they won't go anywhere.
"We could see a worse case scenario than Brexit if firms aren't prepared, but hopefully it won't be that bad. If it does get really bad, no one will want to go to football, pubs, restaurants or go around the market, people just won't want to do this."
But bosses said they were prepared. Robert Bradley, centre manager at Castle Quarter, said: "We take the threat of Covid-19 very seriously. The shopping centre is prepared and has measures in place."
David Field, chief executive at Banham Zoo and Africa Alive!, said: "We are following government advice, we are staying calm but we would close our zoos if the government advice was to do so."
A spokeswoman from Aviva said: "We have robust plans in place to ensure we would be able to continue to serve our customers in case of an office lock-down. We are prepared for mass quarantine or enforced restricted access to key locations where services are provided."
Dr Chris Bushby, chief executive at Norfolk-based cancer charity the Big C, said: "As a cancer charity and employer, we take the health and welfare of our service-users and staff very seriously. While the current risk to individuals from Covid-19 remains low, we are well prepared if this situation should change."
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