Sat Apr 24

Here we go again — Perth's snap lockdown raises familiar hotel quarantine questions

Written by Hassan Vally, Associate Professor, La Trobe University

Perth is the latest Australian city to head into a snap lockdown aimed at stamping out a coronavirus cluster resulting from another breach in CBD hotel quarantine.

The three-day lockdown, covering Perth and the Peel region south of the city, comes in response to news a 54-year-old man evidently contracted COVID-19 from guests in an adjoining room. After leaving quarantine he then visited several locations around the city and infected a friend — Perth’s first case of community transmission in more than a year — before boarding a plane to Melbourne with 257 passengers on April 21 and subsequently testing positive.

If we needed it, this incident is another reminder the COVID epidemic is not over, and we’re still vulnerable to outbreaks in Australia.

Until we get a large proportion of the population vaccinated — right across the world, as well as in Australia — we have to be vigilant to the very real threat the disease will re-enter our communities.

The latest lockdown prompts several questions. None of these questions are new, and none of them has a clear-cut answer, but we have to keep asking them as we strive to understand as much as we can from this type of situation.

Is the lockdown in Perth necessary?

The question of whether a lockdown is warranted cannot be definitively answered. It’s a judgement call based on a complex cost-benefit analysis, which in turn is limited by a number of unknowns.

The key consideration is the level of risk the authorities are willing to accept regarding the possibility of further community transmission. WA Premier Mark McGowan, as he has clearly articulated previously and repeated in his press conference yesterday, is not willing to “take any chances with the virus”. So in this regard, his decision to implement a circuit-breaker lockdown is consistent with a well articulated philosophy.

The rationale here is clear: it is much better to pay a price now, than have bear much bigger costs further down the track.

Given that the man at the centre of the cluster spent five days moving through the community while potentially infectious, there has conceivably been an opportunity for the virus to have been spread to others. However, somewhat reassuringly, he was asymptomatic right up to being tested in Melbourne, and so makes it less likely he has transmitted the disease to anyone in Perth, or while in transit to Melbourne or at Melbourne airport.

Regardless, the aim of the lockdown is to limit contact between people for a period of time, which limits any further spread of the virus and allows public health authorities to get ahead of the situation.

Will Melbourne need a lockdown too?

The exposure to risk of community transmission in Melbourne is quite different to the exposure in Perth and Peel. The threat posed by the case, even if he was shedding virus on the aircraft while asymptomatic, should be able to be contained.

The case, having been notified by authorities at the airport that he was a contact of a hotel case in Perth, went straight home and had no contact with others and upon testing positive went into quarantine.

His close contacts on the aircraft all went into isolation before they should have had a chance to become infectious, so even if they are infected they won’t have had a chance to pass it on. Melbourne Airport Terminal One between 6.30 and 7.30pm on Wednesday April 21 has also been declared a tier 2 exposure site, so anyone who was there at the same time is required to isolate, get tested, and remain isolated until they get a negative result.

This looks to be a really effective public health response with a very good chance of preventing community spread. You can never be definitive about anything to do with COVID, but I am confident this threat will be brought under control.

Is it time to reconsider hotel quarantine?

This is the most pressing question to come out of this event. Yet again we have an example of transmission of the virus within hotel quarantine, and yet again aerosol transmission is the most likely explanation.

The more these types of events happen, and the more costly lockdowns we have to endure, the louder will be the calls for purpose-built quarantine centres to be set up away from major cities’ CBDs.

Quarantining in city-centre hotels is a real-time experiment that, even if we’re being generous, has delivered mixed results.

No doubt one of the barriers to purpose-built centres is the time they would take to set up, and the worry that by the time this is done they may not be needed, and would become expensive white elephants.

But if we accept we have years to run with the pandemic — that is, until transmission has been brought under control all around the world — and this will not be the last pandemic we face, we may soon reach a point where the case for this becomes overwhelming.

Authors: Hassan Vally, Associate Professor, La Trobe University