After 76 days of reporting no new coronavirus cases, the Hunter had its first new patient on July 6 when a man tested positive the day after being released from hotel quarantine in Sydney and returning to Newcastle.

The returned traveller passed on the virus to two friends, a couple in their 20s, who tested positive in the week after attending a social gathering with the man.

In the six weeks since, the Hunter has skated, Steven Bradbury-like, on thin ice through a series of close calls.

Visitors carrying the virus from Sydney and the nine Hunter people they have infected have been to shopping centres, clubs, pubs, sports grounds, schools and court houses across the Lower Hunter while potentially infectious, but none has yet led to an outbreak.

A young man from Sydney infected a Port Stephens man in his 60s and six other family members, including a one-year-old child and another child under 10, in mid-July.

But, despite attending a childcare centre in Anna Bay and Tomaree Public School, playing Aussie rules at Don Waring Oval at Nelson Bay, and visiting Salamander Bay Square and Fingal Bay Cafe, family members did not spread the virus. Another of the near misses was a construction worker in his 20s who was at Wallsend Diggers, Hotel Jesmond and Lambton Park Hotel last month. Hunter New England Health conducted thousands of tests after both cases, but none came up positive.

The same goes for Toronto Court House, which was closed for cleaning after a "member of the court" who dined at the Apollo Restaurant in Potts Point later tested positive.

Then three Newcastle brothers, two teenagers who attended separate high schools and a 20-year-old, tested positive two weeks ago after contracting COVID-19 from an unknown source.

The two younger siblings had 260 close contacts between them, including a host of students and staff at St Pius X Adamstown and St Francis Xavier College at Hamilton.

The younger brother was also a member of the Newcastle Jets Academy, and the 20-year-old visited The Bennett Hotel, Greenroof, Sydney Junction Hotel, Sushi Revolution at Hamilton, Wests Lambton, Queens Wharf Hotel and a Jets game.

But the brothers have not infected anyone else, not even their parents, and students and staff deemed close contacts have returned this week to the affected schools after two weeks' quarantine.

Traces of the coronavirus were found in sewage at the Burwood Beach treatment plant last week, prompting Hunter New England Health to warn, somewhat graphically, that at least one person in the surrounding suburbs must be "shedding" the virus.

Yet, no more positive tests and no widespread outbreak.

Laureate Professor Nicholas Talley, a gastroenterologist and epidemiologist at Newcastle University and editor of the Medical Journal of Australia, said the Hunter had been "really lucky".

"There is some evidence that the majority of infected people spread very little, and a minority spread a lot," he said. "Some people dispute this, but I think there is enough evidence to suggest that some people, not deliberately, but because of their infectious state, the amount of virus they have and the amount of virus they transmit, put others at higher risk.

"We have dodged a bullet, and thank goodness."

The Hunter again recorded no new cases on Thursday, marking two weeks without a positive test. NSW reported five new cases in the 24 hours to 8pm on Wednesday, including two people in hotel quarantine and three in south-west Sydney.

HNEH public health physician Dr David Durrheim was cautious about declaring victory in the region's second face-off with the virus.

"The first 14 days are the most critical, but those of us who have been in public health for a long time like to have two incubation periods, 28 days, before we say we're in the clear," he said.

But Dr Durrheim said the lack of positive cases after two weeks of increased testing was a good sign. "We are quite fortunate," he said. "We know from the Sydney and Melbourne experiences that if people who are infected, and infectious, go into high-risk settings and one is a little bit unfortunate, the opportunities for spread are enormous.

"We know that pubs and clubs are high-risk settings, so we were concerned we might get secondary cases based on those experiences in Sydney, so it is a great relief we haven't had any cases, despite a big surge in testing.

"There is a bit of divine providence, and some good fortune, and some good compliance. Clearly we are not through this yet."

He said a COVID-19 vaccine was an "exciting prospect" but "still some distance away".

"Each day we can keep the virus out of our area is a day closer to us having an effective vaccine. That gives us all a bit of hope."