Could 'traffic-light' alerts help Victoria exit lockdown safely?

Today, Victoria recorded 116 new cases of COVID-19, the lowest number of daily cases since June 5.

As the number of new daily confirmed cases begins to decline, we need to consider how to ease restrictions as efficiently as possible without overwhelming health services.

But moving into a “new normal” won’t be simple. At least 94 countries are undergoing or exiting lockdowns to control the COVID-19 pandemic, and governments are looking for sustainable exit strategies that won’t lead to a surge in coronavirus cases.

One option is a traffic-light alert system, which is already being used around the world to classify whether travel is safe and inform restrictions in the classroom.

When can we exit lockdown?

Ultimately, before we exit lockdown, we need to be confident the changes won’t risk yet another wave of infections. The Victorian government has yet to reveal its map for navigating out of lockdown, but it’s likely several key criteria will need to be met before restrictions can be eased.

These include making sure the health-care system can cope, and ensuring a sustained and consistent downturn in deaths and daily “mystery cases”. Mystery cases can’t be linked to any known outbreaks, so close contacts can’t be isolated to limit the spread of the virus. For this reason, a consistent reduction in these cases is especially important.

Read more: Can Victorians stick to the stage 4 rules? Our perception of what others are doing might be the key

Are “traffic light” restrictions a go?

UNSW epidemiologist Mary-Louise McLaws first proposed the traffic light model after the SARS outbreak of 2003, when she was reviewing the response to the Beijing outbreak.

Red, amber and green alerts – similar to those used during the bushfire season – could be used as part of such a system. The level of threat would be based on the average number of new infections over a two-week period. Colour-coded alerts would then signal to the public when mask-wearing is required – much like they warn of the fire-danger level during bushfire season.

Read more: COVID lockdowns have human costs as well as benefits. It's time to consider both

Professor McLaws has suggested hitting 100 new cases per fortnight would prompt a red alert, leading to the reintroduction of measures to stop the spread of the virus. But new cases in the low double figures would give the green light to opening up restaurants, cafes and shops – with social distancing rules still in place.

Why might it be effective?

Researchers from nine countries simulated how different lockdown strategies would impact the spread of the coronavirus. For places such as Melbourne, the researchers suggested an effective approach to lockdowns would be to alternate stricter measures with intervals of relaxed physical distancing.

Read more: As 'lockdown fatigue' sets in, the toll on mental health will require an urgent response

As the city enters the halfway mark of its strict stage four lockdown, Melburnians are beginning to show signs of fatigue. So a traffic light alert approach could be beneficial in combating the difficulties associated with restricted living.

And as Premier Daniel Andrews said, if fatigue gets the better of us, the virus will spread more rapidly, meaning lives will be lost and lockdown will need to be extended.

What are the drawbacks?

Unlike Melbourne’s current six-week lockdown, under the traffic-light system restriction levels could change more regularly depending on the number of cases. This could potentially result in confusion among the public regarding what each colour actually means.

Professor McLaws suggests having a defined number of cases associated with each “colour” could help the public understand when certain restrictions are to be implemented. She proposed changes to current alert levels could be communicated through an app and in the media.

Read more: Here is why you might be feeling tired while on lockdown

Already in use?

Researchers at the Complexity Science Hub Vienna (CSH) have developed a tool that uses the well-known traffic light system to visualise worldwide trends in coronavirus infection. The “CSH Corona Traffic Light” shows countries in green, amber or red based on the confirmed cases within the past two weeks.

Traffic-light systems have also been introduced in Hungary, the United Kingdom, Ireland, Belgium and Mexico to classify travel to other countries as safe or otherwise, depending on the prevalence of coronavirus. And more recently, Austria introduced a traffic-light system as schools began reopening, to determine restrictions in the classroom.

The “non-negotiables”

No matter what type of system Victoria uses to come out of lockdown there will likely be some “non-negotiables” as part of our new normal.

Recent evidence suggests wearing face masks reduces the risk of catching and spreading coronavirus. And face masks will probably continue to be a feature of Victoria’s pandemic response after the loosening of stage four restrictions.

Effective testing, contact tracing and isolation strategies, as well as efforts to protect our most vulnerable, should also be consistently kept in place.