As Daniel Andrews signals “significant steps” will be taken to ease Victoria’s Covid rules on Sunday, there is ever more pointed attention to the number five. Five is the target set for the rolling 14-day case average that will allow us to move to the next step of easing restrictions on our journey to social and economic recovery.
This isn’t surprising to infectious diseases epidemiologists because at small numbers, chance effects dominate the picture. Infected individuals will have different numbers of contacts, or slight differences in infectiousness. The minor day-on-day fluctuations we’re seeing are entirely anticipated as those last smouldering embers are stamped out.
Any expectation of an elegant linear decline to zero is misguided and will hold us back unnecessarily.
So instead of being discouraged by the failure to meet five, we should be encouraged by the stability of close to 10. Victorians should celebrate the success of all their efforts to suppress the spread of this virus, given daily reports of new cases in excess of 700 at the peak. As of 15 October, we had a total of 175 active cases across the state, of which 21 were in hospital .
While lockdown was painful, it has convincingly done its job of putting a brake on widespread community transmission.
But stay at home orders won’t sustain us into the future. And they’re a disproportionate response to the current epidemiology. At these small case numbers we need to move from whole-of-society measures to intensive case targeted response mode. Proven effective public health actions include “back-tracking”, tracing contacts of contacts, and asking those at risk of exposure to isolate for 14 days. We need to put a “ring of steel” around each newly identified case, not a whole city.
The recent incursion into Shepparton shows that we have challenges ahead. The “new normal” will inevitably have outbreaks, epidemic “spot fires” which must be put out. Identification and quarantine of first- and second-degree contacts as a precautionary measure. Strong community engagement and participation in testing to prevent infections spreading through families and communities.
Our public health response capacity has been massively expanded and decentralised over the course of this pandemic. With small case numbers, follow-up of extended contacts is sensible and achievable. Testing capacity is high and turnaround times to reporting are quick. We must have confidence in these system investments.
But this doesn’t mean we’re all off the hook now. No infectious diseases policy experts are advocating for an immediate return to life as normal. The onus is still on all of us to make sensible behavioural choices to prevent a resurgence of infections.
Wherever we are or whoever we meet, our actions are important. The ongoing excellent adherence of Victorians to the personal behaviours that minimise infection risk provides further support for safe easing of restrictions. The chance that chains of transmission will take off is currently the lowest in Australia.
Minimising the opportunities for “super-spreading” events remains a key focus. That’s why we still need to keep mixing group sizes low in public and private settings. Outdoor mixing is safer, so the numbers can be more generous. Covid-safe practices in workplaces and hospitality settings are essential to reduce the risk of transmission between social groups and households.
It’s time for us to release blanket restrictions. They have served their purpose. Their harms now outweigh their benefits. Victorians were delivered a carefully considered roadmap over a month ago, with a series of policy settings related to an active case target. We’ve reached the intention behind the goal represented by five and should proceed as planned.
For months now, we’ve been hearing that staying apart keeps us together. We can move a little closer in the knowledge that we can stay safe over the longer term by working together.
• University of Melbourne professor Jodie McVernon is the director of Doherty Epidemiology
• University of Melbourne professor James McCaw is a mathematical biologist and infectious diseases epidemiologist with a PhD in theoretical physics