Seen with a long view, the recent spike in positive coronavirus cases in Ballarat is unfortunate, but indicates contact tracing and self-isolation is working to keep numbers down, according to an epidemiologist.
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Chair in epidemiology at Deakin University, Catherine Bennett, said it was important rural Victoria does not "lose its advantage" in controlling cases.
"The local knowledge and limited number of cases, and effort in the local community to identify people who could have been a risk and encourage them into isolation and testing, that's everything," she said.
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Ballarat recorded its first case in months on July 16, and another 11 cases in the week that followed.
The city then went a week with only one new case recorded, before numbers began climbing again.
Professor Bennett said this indicated a "point source outbreak" - a single case returning to the community and infecting others.
"That first new case, we don't know when, but it's likely you did have a first case sometime in mid-July," she said.
"Then you had a wave of positive cases over the week of the 16th of July and beyond that were probably secondary infections associated with that first case."
As more people became aware of the new infections and were tested, and contact tracing got underway, the impact was limited, but there would still be further cases.
"Then, the week starting the 31st, you get a second wave, which is now the next level of contact," Professor Bennett said.
"The fact that this current wave has similar numbers, one to four cases per day max, is a good sign so far this isn't escalating.
"If you get something similar to the first (in the) second, it shows contact tracing is working to minimise chances of the next round of infections based on each group of contacts as you go."
The analysis proved the strength of contact tracing in tight communities in Ballarat, and how it can limit rapid growth as seen in other regional cities.
"If this wave's associated with the initial introduction, it's really important for close contacts to bunker down, even before they have a chance to get tested, and even if they have a negative test," Professor Bennett added.
"If someone's positive and they get better, it doesn't mean they're not still infectious - keeping people away from others for the full two week cycle is really important to make sure numbers don't get bigger."
It's also important to analyse the numbers while understanding the timing of restrictions - Ballarat has been under stage three since August 5, which is after testing and contact tracing began turning up new cases from the July 16 case.
Professor Bennett cautioned there could still be more cases uncovered in the short term.
"There's always a two week lag time - so if there are still the odd cases in the community because someone was infected without realising, this next fortnight with everyone more isolated and less contacts is going to help close down this local outbreak as well," she said.
"If everyone has fewer contacts, that helps the contact tracing work well.
"If anyone's been missed, then their isolation through stage 3 helps, that's much less likely (for the virus) to be passed on to someone else."
Ballarat has now recorded 39 cases, 17 of which are active.
Remember to always maintain good hand hygiene, wear a mask when in public, and keep a 1.5 metre distance from others at all times.
Right now there are only four reasons to leave your home in Ballarat during stage three restrictions: care and caregiving, local exercise, shopping for necessary items, and for work or study if you are unable to do so from home.
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Victoria Police are enforcing restrictions, and penalties apply.
Anyone with the slightest symptoms is urged to get a test immediately, and must self-isolate until results come back - phone 4311 1571 to make an appointment.
For more information, visit the Victorian Department of Human Services website, or phone the hotline on 1800 675 398 for advice if you are displaying symptoms.
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