NSW Health alert patrons of Shellharbour Coffee Club to isolate even if getting a negative COVID test

NSW Health updated their advice on Saturday evening for the Coffee Club at Stockland Shellharbour, revising that anyone who visited on December 27 between 11:30am-12:45pm had to isolate for 14 days, regardless of a negative test result for COVID-19.

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Manager of the family-owned business Jaryd Ramsey said their cafe - and the general shopping district - had seen a stark decline in trade since being named on health advice.

"Our regular customers have been very supportive ... a lot have come in to show their support," he told the Mercury.

"But the entire shopping centre as well as us, has had a massive impact. For the numbers coming through at this time of year, I'd say we're down about 60 per cent - so it's a massive decrease."

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Since the latest outbreak on Sydney's Northern Beaches, there has so far been three positive cases of COVID-19 in Wollongong - with genetic testing linking the virus strain to Avalon.

However, Chief Health Officer Dr Kerry Chant said on Sunday they were still searching for "the missing link" and how the virus made its way to the Illawarra.

Mr Ramsey pleaded with the public to stay home if feeling unwell for the safety of the public, and for local business.

"If somebody is moving around with the disease it does put a lot of livelihoods and businesses at risk," he said.

"We've had a person here for a period of time and we've had 11 staff who have now had to isolate for 14 days."

With minimal staff they've now had to reduce their trading hours to accommodate also.

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It comes as masks are now be compulsory in many indoor settings - enforceable with a $200 fine from Monday - across all of Greater Sydney (including Wollongong, the Central Coast and the Nepean Blue Mountains).

People will be required to wear masks when shopping, in shopping centres, on public transport, at an indoor entertainment centre like a cinema or theatre. Places of worship, hair and beauty salons, gaming venues and staff at hospitality venues are also included.

Children under 12 are exempt from the mask wearing rules.

As of Sunday, mask wearing was not mandatory in Shellharbour, though many businesses have been asking customers to please oblige.

There are more than 350 COVID-19 testing locations across NSW, many of which are open seven days a week. To find your nearest clinic visit: https://www.nsw.gov.au/.../how-to-protect.../clinics or contact your GP.

NSW Health urges anyone in NSW with even the mildest symptoms, such as headache, fatigue, cough, sore throat or runny nose, to come forward immediately for testing, then isolate until they receive a negative result.