Victoria’s hard but successful road to local elimination

The lessons from Australia’s second COVID-19 wave are many, but most of all it has taught us that, while the fight only gets harder as you move through waves, it is possible to win against this virus. As case numbers increase you will find new cracks in your public health system, but Victoria has shown that systems can be rebuilt whilst under pandemic strain and that the public can stay the course, even under extensive lockdown in both degree and duration. With these assets working together, local transmission can be eliminated. The time taken will depend on how strong the public health response is at the outset.

Victoria, Australia, with a population of 6,359,000, didn’t even realise that the first wave of COVID-19 infections was over and community transmission about to die out at the time the second wave insidiously took root in the community. Australia had been so effective in moving early into a hard 6-week lockdown by the end of March that community transmission had been contained and only one large work-place outbreak associated with a meatworks facility occupied the health department’s time through to June.

By early June, three weeks after the staged easing of restrictions commenced, we enjoyed days with only one or two new cases, and the odd one with zero. Testing blitzes in the wider community from late April did not identify new cases and reassured us that community transmission was not an ongoing threat.

The second wave began with breaches of hotel quarantine at two separate sites that quickly led to infections in a number of staff. These cases were buried in the tail of the first wave and so did not set alarm bells off in the wider community. But in fact, we now know this was the critical tipping point as the workers who contracted the virus, some causal staff working across multiple work places, took the virus home to large households often shared with other casual workers, and also to their wider local community networks.

The rapid escalation of new cases that followed would have tested the best of contact tracing systems – From 13 new cases on June 21, to 68 a week later and 687 per day by August 4. The main driver of the rapid escalation in new cases was work-place outbreaks where the virus could cycle among workers in high transmission risk settings; meat works, freight and distribution centres and, from early on the second wave, aged care residential homes. Hospitals soon followed and in the second half of the wave healthcare workers made-up one-third of all new cases, with another third were their close contacts. Devastatingly, eight hundred lives were lost on the second wave, with the vast majority of these were in aged care.

The first wave had been dominated by cases among returned international travellers. By mid-March, the decision was made to preserve Victoria’s testing capacity for those travellers and their immediate contacts. Even with symptoms, members of the wider community could not be tested unless they were contacts of known cases, or were admitted to hospital with a severe community-onset pneumonia not otherwise explained. In effect, we were not only protecting out laboratories from overload, we were also protecting our contact tracing system from a significant stress test. It was ostensibly the lockdown that contained community transmission the first wave of community transmission, and we did not realise how vulnerable the state would be in the face of a second wave.

There were many daunting challenges for Victoria in the second wave; the different epidemic dynamics we were battling with workplaces involved that amplified transmission, the incursion if the virus into the healthcare system leading to 3,573 staff being infected and many more furloughed following workplace exposure, and multiple simultaneous aged care outbreaks leading to a four percent case-fatality rate compared with one percent in the first wave. We were also dealing with lockdown fatigue and anger and blame over the source of the second wave. But by far the greatest challenge was that the contact tracing system and underlying resourcing and infrastructure were not up to the task.

Mandatory masks were introduced outside the home by mid-July and this combination brought the reproduction number down below one. But containment was still slow. Ten days later further strict lockdown rules were brought in – engineering in compliance with additional rules limiting any movement to five kilometres from home unless a permitted worker and a night-time curfew from 8 pm to 5 am. Only one person could go to the shops for essential items once a day, and each person was allowed outside for one hour of exercise. The restrictions were backed up by heavy fines.

By mid-August, six weeks in, we were still averaging 300 new cases per day, even with much more strict measures in place. There were still new workplaces outbreaks starting and some still smouldered that had been running since June. Increasingly the capacity of the contact tracing systems was being questioned, as well as the availability of personal protective equipment and the management of infection control in Aged Care, but also in the hospital systems. Arguably lockdown had done its job, but the virus was continually being seeded back into the community from workplace outbreaks.

Victorians dug deep. The State Government announced a series of fundamental changes to the public health response to improve community engagement by embedding local public health units in the regions and metropolitan areas, cranking up the testing and contact tracing to dramatically shorten the turnaround time from a positive case notification to isolation and quarantine of close contacts. Improvements in infection control support for aged care and to contain hospital outbreaks started to pay off. Through the long tail, the city of Melbourne stayed in strict lockdown, isolated from the rest of the State, with ambitious low case number goals to reach before any relaxation of restrictions. Yet voluntary testing rates stayed up, and compliance with the restrictions was strong enough to prevent wider spread of the virus still being seeded back into the community from workplaces.

One of the State’s most significant advances was introducing a more aggressive contact tracing approach – asking close contacts of the close contacts of a known case to quarantine until it was known whether the intermediary contact had been infected. That way, even if secondary transmission had occurred, those exposed were isolated before they were infectious. This final response tactic was the game-changer, and the last community clusters could be brought under control. Case ascertainment was so effective using this technique, as soon as these outbreaks were closed off, no new cases were reported. This has been out story for 35 days now.

Of course, Australia has advantages as an island nation in the face of a pandemic, but our borders are not airtight and we continue to face the threat of the virus escaping into the community, as we saw again in Sydney just this week. Victorians are rightfully proud of their success, enduring 112 days of strict lockdown to buy the State the precious time needed to strengthen our health systems. We are now not only free of local transmission for the second time, but have a public health response second to none. This is the true reward for the stoic Victorian population, a success story collectively owned by over six million people, and hard-won protection from a third wave.