World News

Roadmap takes us on a Victorian rollercoaster to Christmas

For our free coronavirus pandemic coverage, learn more here.

The long-awaited Victorian roadmap has been released.

It looks good. At first pass it is a sensible balance of cautious opening up and trying to keep within the principles of the national plan for reopening.

Victorian Premier Daniel Andrews.Credit:Eddie Jim

As emphasised by Premier Daniel Andrews on Sunday, it is based on modelling. We know though that the virus does not listen to the modelling and behave as we forecast. Indeed, case numbers in Victoria may have just plateaued, whereas the Burnet modelling underlying the roadmap forecast that daily case numbers under our current public health and social measure settings (if continued indefinitely) would peak at 1400-2900 cases in the second half of October.

Some key features of the roadmap include an incremental opening up of schools. Most kids will only be back at school, and for only a few days a week, by the end of October when the 70 per cent double-dose vaccinated target is achieved. This will be very disappointing to many parents and children. However, the reality is that Delta spreads among kids – more so that did pre-Delta variants.

In my view we need a bit more flesh on the bones of what the Premier hinted at on Sunday: “We will monitor every hour, every day the number of people in hospital.” This was couched in terms of being able to support the health system and staff.

But there is a bigger feedback loop than this. A feedback loop that alters our opening up as the actual data comes in. And there is a ceiling or envelope we need to work within. That is a maximum tolerable daily number of cases that in turn corresponds to a maximum hospital and ICU bed occupancy we can manage.

We need to consider the maximum hospital and ICU bed occupancy we can manage.Credit:Nine

Just because a roadMap says “do X at 80 per cent double vaccinated” does not mean we do X if it looks like we will crash through this envelope and stretch the health services so much that case fatality for people with COVID-19 goes up and quality of care for people with non-COVID-19 conditions deteriorates.

What is the limit our health services can cope with? There is no magic number here.

Let’s assume – learning from NSW – that 2000 daily cases is a maximum current limit, and corresponds about 1:1 to the number of hospital beds occupied on a given day. And that our maximum tolerable limit might be 2500 people in bed at any one point (which is also the threshold used in the Burnet modelling underpinning the plan).

As more people get vaccinated, 2500 people in a hospital bed on any given day will correspond to something like 3000 to 4000 daily notified cases a couple of weeks before – as proportionately more infections occur in the vaccinated with consequently less severe disease.

As more people get vaccinated, the plan changes.Credit:Eddie Jim

Then the trick, the agile, real-time, week-to-week task of rolling out this roadmap, is to keep within that envelope of about 3000 to 4000 daily cases by the end of year (I will assume 3000 minimum to be safe), keeping the number of people in hospital at any one point under a 2500 ceiling.

If we think about hypothetical epidemic curves (for real modelled ones, go to the Burnet modelling) for each of the different settings we move to. The settings we plan to adopt when we hit 80 per cent single vaccinated, 70 per cent double vaccinated, and 80 per cent double vaccinated.

It will look like is a series of humps, each new hump going up again due to further loosening of public health and social measures before bending back down again as the increasing vaccine coverage catches up. Stringing it together, it will look like a roller coaster ride from here until Christmas.

What we are aiming to do is “ride the rollercoaster” to Christmas, keeping daily cases beneath 3000 per day (hopefully much less). It is a roller coaster because we jump from one epidemic curve to another, each one with a peak further into the future that is a balance between looser public health and social measure settings and vaccine coverage that is chasing down each next curve.

There are many assumptions in drawing these curves. Predicting the future is inherently uncertain!

So we need to be agile. If at any point between now and Christmas it looks like we are at risk of tracking above the roller coaster line, and crashing through our ceiling of tolerable hospital bed occupancy, we will either need to delay the next release of measures – or even retreat a little with, say, sending kids back home for a week or two.

On the other hand, maybe we will track beneath the roller coaster curve, and have the luxury of deciding between opening up faster or banking the lower case numbers to save up for an ever better Christmas with interstate and international travel. (Personally, I would take the latter – but we have a few months for this debate, if we track well.)

I am sure that the Premier, the Minister of Health and the Chief Health Officer all have the above in the back of their minds. My purpose here is to expound this need for agile tweaking of the plan, and to get you ready for a rollercoaster.

Just like you, I hope that this rollercoaster ride will occur at lower case numbers that our upper limit. Fasten your seatbelts, and let’s roll.

Professor Tony Blakely is an epidemiologist and public health medicine specialist at the University of Melbourne.

Most Viewed in National

From our partners

Source: Read Full Article