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(Image: AAP Image/David Crosling)

Mild mitigation measures will not be enough to stop a massive spike in coronavirus cases overwhelming the health system, argues a paper released by researchers at Imperial College London.

Policies such as widespread social distancing, quarantining of people with exposure and the closure of schools and universities will need to be in place for many months to have any chance of seriously suppressing COVID-19 cases, the paper argues.

“The world is facing the most serious public health crisis in generations. Here we provide concrete estimates of the scale of the threat countries now face,” says Professor Neil Ferguson, head of the Abdul Latif Jameel Institute for Disease and Emergency Analytics at Imperial College.

They focus on two broad scenarios: essentially, slowing the spread to make it more manageable, and reducing spread enough that infections fall.

“We use the latest estimates of severity to show that policy strategies which aim to mitigate the epidemic might halve deaths and reduce peak healthcare demand by two-thirds, but that this will not be enough to prevent health systems being overwhelmed.

“More intensive, and socially disruptive interventions will therefore be required to suppress transmission to low levels. It is likely such measures — most notably, large scale social distancing — will need to be in place for many months, perhaps until a vaccine becomes available.

The paper has been credited with changing the United Kingdom’s strategy on the outbreak. Initially the UK was pursuing a more hands-off approach, with the nation’s chief scientific advisor suggesting 60% of the population needed to contract the disease to reach herd immunity to help control it in the long term.

But the Imperial College paper argues that strategies focusing on “slowing but not necessarily stopping” epidemic spread “would still likely result in hundreds of thousands of deaths and health systems (most notably intensive care units) being overwhelmed many times over”.

In an unmitigated epidemic scenario, the researchers predict 510,000 deaths in the UK, and over two million in the United States, the two countries included in their modelling — though they believe results would be similar for other rich countries. At the peak, demand for intensive and critical care beds would exceed capacity by 30 times.

Undertaking moderately intrusive measures — such as case isolation, household quarantine and social distancing of just the elderly — would lead to perhaps 250,000 deaths in the UK and more than one million deaths in the United States. Even under optimistic assumptions, surge limits for both general ward and ICU beds would be exceeded by at least 8-fold.

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