I don’t think NSW delayed too long – but time will tell
I don’t think New South Wales waited too long to “lock down”. Lockdowns cause a lot of social and economic harms, so we need to ensure they are not put in place too early and before other less severe forms of restrictions would have achieved the same result – namely stopping ongoing and ever-increasing transmission rates.
In my view the main criterion for a lockdown is when we see a large number of unlinked cases occurring. If there are a lot of “mystery” cases, then for every case identified there is a least one other infected person still freely moving around in the community. But in NSW so far, while there have been increasing daily new case numbers, nearly all the identified cases are linked. Most are already in isolation or at least aware they are casual contacts.
Another factor that influences decisions on restrictions are increasingly large numbers of new cases per day. Once you get large numbers of new cases per day, your case-finding abilities can get overwhelmed. So far that hasn’t happened in NSW, but that will become a limiting factor if daily numbers continue to increase.
With increasing numbers of new cases, more severe restrictions are needed to limit further spread if many of these people were not already in isolation. But to answer the question of how much of a difference a lockdown in NSW would have made and its timing, we will only get a good idea through the number of new cases occurring per day over the next week and how many of these were not already in “quarantine” at home.
We need to remember that any intervention, including lockdowns, will take at least five to seven days before we see an effect on case numbers. This is because the average incubation period is about five days. So the data over the next week, and more importantly a week from now, will be critical to help answer this question.
Peter Collignon is an infectious diseases physician and microbiologist at the Australian National University and a member of the Infection Control Expert Group which advises the Australian Health Protection Principal Committee on infection prevention and control issues.
Going hard and fast is the only way to beat exponential growth
There’s been a lot of talk about NSW taking a “proportionate” response to Covid-19, but in reality, taking decisive action to eliminate the virus delivers the best outcomes for both health and the economy. It’s simply not possible to “learn to live” with Covid-19 before we’ve achieved herd immunity through vaccination.
Because the virus grows exponentially, having even just a few cases in the community leaves Australia on a knife-edge. This was always the case, but the Delta variant has magnified the risk. If no restrictions were in place, a person infected with the original strain of the virus would infect about two-and-a-half other people on average. The Delta variant has increased that to six. Keep putting six times six into your calculator and see what you come up with. Going “hard and fast” is the only way to beat exponential growth.
Once there’s transmission of the Delta variant in the community, it’s likely that a lockdown is the only way to get rid of it. But lockdowns are most effective when they’re used early. Early action not only gives the best chance of stamping out Covid-19 quickly, it also results in faster economic recovery. A short but sharp lockdown is likely to deliver better health and economic outcomes than delaying action and then subsequently having to introduce prolonged restrictions.
Had the NSW government reacted swiftly with a snap lockdown in the early stages of the outbreak, it may have been able to avoid the longer lockdown that Sydney now faces. If we’ve learned anything from Melbourne’s second wave, it’s that there’s no way to avoid a long lockdown if the virus has built up momentum. I hope it’s not too late for Sydney to avoid that.
Zoë Hyde is an epidemiologist based at the University of Western Australia
There is no place for politics when it comes to fighting the virus
It’s important to remember that the decision to go into lockdown is dependent on two main considerations. Firstly, it involves assessing the risk of Covid transmission getting away from you based on the information available, which is always incomplete. And secondly, it is dependent on your tolerance for risk; that is, the level of risk you are willing to take on that things could get away from you if you don’t impose strong restrictions.
The decision to go into lockdown is one that shouldn’t be taken lightly. Lockdowns are brutal and costly, both personally and economically. So there’s no doubt that trying to avoid a lockdown is a worthwhile aspiration. They are a sledgehammer, which may be necessary sometimes, but it’s better for everyone if we can achieve the same result by using a scalpel.
So what can we make of what has happened in NSW? Despite the numbers of cases that were identified over the past week, I think there was a reasonable argument early on that this cluster could be brought under control without a lockdown given that cases were linked and it appeared that contact tracers were keeping up with transmission. But things can change quickly, and the discovery of a separate and previously undetected chain of transmission involving the seafood handler tipped the risk-benefit equation, which was delicately balanced, in a drastic way, making the decision for a lockdown the only course of action.
Whether NSW should have called a lockdown earlier will be debated vigorously, and much will rest on how things transpire in the coming weeks. What is clear is that we are going to have to start to get a bit more tolerant of risk as time goes on. However, the difficulty is that the landscape is constantly changing, with the latest challenge being factoring in the increased transmissibility of new variants of the SARS-Cov-2 virus.
The one thing that is really clear, however, is that there is no place for politics when it comes to fighting the virus and like the rest of Australia I am hoping that NSW is able to get on top of this situation as soon as possible.
Hassan Vally is an epidemiologist and associate professor at La Trobe University