Victorian Premier Daniel Andrews today announced the most significant easing of Melbourne’s coronavirus restrictions since the state went into “stage 3” lockdown on July 9.
From 11.59pm on Tuesday night, retail, restaurants, cafes and bars will finally be able to open up in Melbourne. Gatherings of up to ten people outdoors are now allowed from any number of households, and the four reasons to leave your home have been abolished. Outdoor contact sport for under-18s returns, as does outdoor non-contact sport for all ages.
Residents will have to wait until Tuesday for confirmation on how many visitors they’ll be allowed in their homes, as Andrews reiterated that indoor gatherings represent the highest risk of transmission. But he ruled out a “bubble” approach, which I think is smart — if the rules are too complicated they become harder to follow.
The 25km travel limit and the “ring of steel” between Melbourne and regional Victoria will be removed from midnight on November 8. Gyms and fitness centres will also reopen from that date.
Second wave defeated
Although we’ve been through a rollercoaster of emotions over the past 36 hours, the recording of zero new COVID-19 cases today and the further relaxing of restrictions marks the official end of the second wave in Victoria.
By working together, after the peak of more than 700 new cases a day in early August, Victorians have brought virus transmission under control, and now squashed it completely. For this, all Victorians should be commended.
This is a significant achievement — our equivalent of overcoming a ten-goal deficit at half-time in the grand final and starting the final quarter with a slender lead. Although the work is not done, and we’re exhausted, we should celebrate what we have been able to achieve.
Of course, we cannot ignore what happened in the northern suburbs of Melbourne this past week. The timing of this cluster was unfortunate, and the resulting postponement of the announcement of the relaxing of restrictions yesterday was, for many of us, devastating. But to frame it as a positive, if there was any lingering uncertainty about our capacity to respond to clusters, this should now be laid to rest.
The incident provided the perfect opportunity to show how effectively we can handle clusters. By targeting contacts of known cases as well as contacts of contacts, we’ve shown that, rather than crude geographic lockdowns, we can control transmission of the virus by bringing lockdowns to where the cases are.
This is what best-practice public health looks like, and the government should be commended for continuing to refine and improve the public health response to these clusters. We should now be able to place our trust in the public health response.
With relaxed restrictions comes personal responsibility
But it’s important to be aware these newly regained freedoms come with obligations. As prescribed restrictions ease, the pendulum swings towards individuals taking responsibility for managing their risks, rather than government telling you what you can and can’t do.
As Andrews said, “this virus isn’t going away”. So it’s expected that we continue all of the behaviours we’ve come to know, such as regular and frequent hand-washing, practising physical distancing, avoiding large crowds, and wearing masks when you leave the house.
And most important of all, make sure you get tested as soon as possible if you develop even the slightest of symptoms.
Victorians have shown how responsible they are, it’s time to reward them with the trust they’ve earned.
Europe is again in the grip of a COVID-19 resurgence, with outbreak hot-spots in the United Kingdom, Spain and France each reporting thousands of new daily cases.
The level of infections are now higher than in March and April across many countries, after restrictions were significantly eased over summer. But now many areas are being forced to re-introduce varying levels of restrictions, though most countries are resisting nationwide lockdowns.
Second wave peaks are significantly higher than in the first wave
During the country’s first wave, France’s daily new case numbers reached a peak of just over 7,500 on March 31. Its new peak was recorded on Sunday with 26,675 new cases in the previous 24 hours, over three times higher than the first peak.
In the first wave, the UK had a peak number of 7,860 daily cases on April 10, which has jumped to a peak of 17,540 on October 8.
However, these are only the new cases reported from the testing sites. These numbers are known to underestimate the true number of infections, because many people have no symptoms and so are unlikely to get tested.
Researchers from the Imperial College London tested 175,000 people in the UK — whether they reported symptoms or not. They found 824 were positive, and used this to estimate there were around 45,000 new daily infections between September 18 and October 5. This would amount to more than double, or often more than triple, the official daily new positive tests results reported during that time.
‘Restriction fatigue’ bites amid European summer
Summer is the vacation season and a “golden goose” for European economies, so many countries lifted various restrictions to enable tourism.
Many people had a sense of regained freedom and a feeling of lesser need to adhere to physical distancing measures over the summer months. This was reflected in another ongoing research project by Imperial College. Researchers found many Europeans surveyed had relaxed their behaviour in the last few months, compared to in April.
Indeed, Europe’s second wave points to an element of restriction fatigue after months of restrictions on daily life and with economies faltering. WHO Europe director Dr Hans Kluge acknowledged “It is easy and natural to feel apathetic and demotivated, to experience fatigue”. He called on European authorities to listen to the public and work with them in “new, innovative ways” to reinvigorate the fight against COVID-19.
Restrictions are returning, but no national lockdowns yet
In recent weeks, many European leaders have announced targeted, localised restrictions, but no national lockdowns as yet.
The French government reimposed restrictions in many urban areas, including limiting the capacity of restaurants and classrooms, and closing bars and gyms.
Spanish Prime Minister Pedro Sánchez introduced travel restrictions to and from Madrid, which inspired protests and earned his government a “criminal and totalitarian” label from dissenters and their political opponents on the far-right.
Like France and Spain, the UK government is not planning to reimpose a national lockdown despite a record number of cases. Prime Minister Boris Johnson has opted for “a balanced approach” enforcing a three-tier alert system across England — medium, high, and very high — depending on the severity of outbreaks.
Before the emergence of the European second wave, Germany was a role model for its successful approach to combating the virus. This image will be hard to sustain though, as in the past few days the country has experienced its highest daily increase in cases since its peak in early April. The country’s capital Berlin, famed for its rich nightlife, entered its first curfew in 70 years from October 10.
Europe could look to the success of countries like Vietnam
By contrast, several South-East Asian countries are doing exceptionally well. Over the past two weeks, Vietnam, Thailand and Cambodia have reported around 0-5 daily new cases on average despite dense populations. It’s important to note there may be undercounting in case counts and deaths, but this doesn’t detract from the overwhelming success these countries have had.
Vietnam’s total number of cases is just 1,113, which is extremely low for a population of nearly 100 million. One tactic used by health authorities has been targeted testing, where they’ve focused on high-risk individuals and on buildings and neighbourhoods where there have been confirmed cases. Health authorities have also implemented extensive contact tracing, and aimed to identify those at risk of exposure regardless of symptoms. The country also set up quarantine facilities for infected people and international travellers, minimising spread inside households.
In Thailand, health volunteers have been visiting areas of clusters, triaging cases, sending people with symptoms to medical clinics for testing, and dispelling rumours and misinformation. They have also taught people how to properly wash their hands, emphasised the importance of masks, and dispensed hand sanitisers. In addition, the Thai Department of Disease Control has been contacting hospital staff from every province to ensure they know how to detect cases and how they can prevent outbreaks in the hospitals. This education, and the army of volunteers, have helped keep total number of cases to just over 3,500.
Despite having a relatively weak medical system, Cambodia’s total case numbers are extremely low at just 283, with zero deaths. The country has conducted extensive contact tracing, utilising 2,900 health-care workers who were trained in contact tracing at the start of the year. The country also went into a strict lockdown early in the pandemic including by shutting schools and entertainment venues. Travel has also been restricted. Almost 80% of Cambodia’s population lives in rural areas with a low population density, making it easier to manage the spread and to allocate resources to denser, higher-risk locations such as Phnom Penh, Siem Reap and Sihanoukville.
Having experienced the SARS and avian flu epidemics, many Asian countries took the threat of COVID-19 seriously right from the beginning. In addition, many countries implemented strict mask wearing and physical distancing early. Targeted testing, education and the involvement of the community are critical in responding to COVID-19.
It’s hard to recall a time when we didn’t nervously await the announcement of Victoria’s daily COVID-19 case numbers each morning.
It was certainly disconcerting when the state recorded more than 700 new cases on two occasions not long ago.
And likewise, now that we’ve seen a few consecutive days of around 300-400 cases, it’s tempting to ask whether the peak of Victoria’s second wave is behind us.
The good news is, current daily case numbers do indicate we’ve passed the peak of the second wave. But I would suggest we actually reached the peak at the end of July, and the reported case numbers are only now catching up.
Daily case numbers versus new infections
Before we can answer the question of whether Victoria has passed the peak of its second wave, we need to be clear about what we’re asking. Although it’s natural to focus on the reported case numbers because they’re highly visible, the outbreak’s progress is in fact driven by the number of new infections.
COVID-19 infections can take up to two weeks to be diagnosed and appear in the official case count. This is because an infected person must first pass through an incubation period (the time between becoming infected and symptoms presenting), and then be tested and wait for their result.
On average, the process takes about one week, but it can vary substantially from person to person.
So today’s case numbers — rather than indicating new infections — actually reflect infections that occurred up to two weeks ago.
In other words, watching the case numbers doesn’t tell us the full story about the current spread of the virus. When asking whether we’ve passed the peak, we really need to focus on the peak in daily infections.
That’s where data analytics come in
We don’t know how many new infections occur each day because infections remain hidden until symptoms develop or there’s some other reason for a person to get tested.
But we do have a good idea of how long it takes for someone to progress from infection to symptoms, and then from symptoms to diagnosis by a positive test.
By combining the observed case numbers with a mathematical model for the progress from infection to diagnosis, we can then reconstruct the pattern of past infections that would have led to the case numbers. This is an epidemiological analysis method called back-projection.
This analysis is an estimate, not an observation. But we can use it to explore whether there’s any evidence infection numbers have peaked, and at what point.
Looking back to the first wave
Earlier in the outbreak I used this approach to evaluate the effectiveness of the government’s control measures. In a study looking at the first wave of infections across Australia, I showed that the timing of government restrictions matched almost exactly with the flattening and downturn of infection numbers.
This was despite the fact case numbers continued to rise after restrictions were introduced. In other words, the case numbers were hiding the good progress that was going on in the background.
By clamping down early, we probably avoided tens of thousands of infections nationally. A recent study published in the Medical Journal of Australia estimated Victoria’s control measures averted between 9,000 and 37,000 cases in July.
Returning to Victoria’s second wave
We can use the same data analytics approach to explore the progress of the recent restrictions in controlling Victoria’s second wave.
My reconstruction of Victoria’s infection numbers during the second wave, shown below, illustrates an early rise in infections during June. This rise likely accelerated in the first half of July, when new infections would have been increasing at a substantially greater rate than was evident in the daily case numbers.
This lag in the case numbers makes it plausible the recent flattening of daily cases is being driven by a much more pronounced decrease in the underlying infection numbers. This is what the reconstructed infection numbers are suggesting in the graph, which shows a peak in late July.
Again, this is an estimate rather than an observation, and the very recent infection numbers have considerable uncertainty. (This is because we work backwards with this analysis, and very few of the most recent infections will have shown up yet in the case numbers.)
Room for optimism, but not complacency
The lower case numbers in recent days suggest we’ve reached and passed the peak of Victoria’s second wave, and my analysis strengthens and supports this. It shows a peak and decline in new infections over the last couple of weeks.
If this is true there’s good reason to be optimistic the tough restrictions will drive the infection curve, and subsequently the case numbers, down even further.
But it’s sobering that my same analyses estimate Victoria has had about 2,000 more infections than case diagnoses. That’s an estimated 2,000 people who are infected but don’t yet know it.
So even if new infections have peaked, as we all hope, there’s plenty of potential for the curve to turn back up again if adherence to the restrictions wavers. Victorians have some reason to be optimistic that the peak has passed, but there’s no room for complacency.
Victoria recorded its largest daily increase of 127 new COVID-19 cases on Monday, 16 more than the previous peak of 111 cases on March 28.
As I recently wrote, there’s no formal definition of what constitutes a second wave, but a reasonable one might be the return of an outbreak where the numbers of new daily cases reach a peak as high or higher than the original one.
By that definition, a second wave has arrived in Victoria. So why isn’t the state back in lockdown?
What can be done to bring the outbreak under control?
The current strategy of mass testing and information campaigns in hotspot areas, and quarantining whole tower blocks, may not be working. Regardless, cases are now appearing outside the hotspot areas, among people who were most likely infected before the latest measures were put in place.
The Victorian government must now seriously consider going back into statewide Stage 3 lockdown restrictions. Under these rules, there are only four reasons to leave your home: shopping for food and supplies, care and caregiving, exercise, and study and work if it can’t be done from home. And exemptions to quarantine rules should not be granted.
Testing should no longer be a choice. People in 14-day quarantine should be tested on day 11, and if they refuse, made to go into another 14 days of quarantine. Breaking quarantine should be a serious offence.
Far better communication is needed to explain why these measures are essential, and health authorities should ensure their messaging also reaches those who do not speak English as a first language.
People should be encouraged to wear face masks whenever outside. There is increasingevidence they are effective in areas of high transmission.
Much more must be done to educate the public about panic buying. If necessary, Australian Defence Force personnel could be used to deliver food and essential supplies to those at high risk, and assist with logistics.
Some people living in border communities will be granted an exemption from this closure, including those whose nearest health provider or place of work is just across the border. Hopefully they will be closely monitored and regularly tested.
Finally, all other states and territories should rally to assist Victoria. It is in everyone’s interest to defeat this outbreak.
Where to from here?
At this stage, the situation is unclear. Daily cases could still rapidly increase, or we could have reached the peak and we might start seeing cases subside. However, the number of new cases each day isn’t necessarily the critical factor. More important is the daily number of new community-acquired infections. Because we have no idea where these people got infected, it makes controlling the situation very difficult.
Other cases are not a major threat as it’s possible to contain them with quarantine and contact tracing. If necessary, additional staff experienced at contact tracing can easily be brought in from other states.
The first epidemic wave was controlled by imposing severe restrictions. Unfortunately, history might have to repeat itself.
Achieving control buys time and allows us to learn more about the virus and the successes and failures of other countries.
But until an effective vaccine arrives, the majority of the population will still lack immunity to COVID-19. This is essentially identical to the position we were in when the first imported cases of the coronavirus arrived in Australia.
While there has been debate about the speed at which restrictions have been introduced, there has been less discussion about how and when these measures can be relaxed without causing another spike in infections.
We outline four broad options available for coming out of lockdown once we have gained initial control:
option 1: we could relax lockdown measures completely, prioritising a return to normal social and economic freedoms over suppressing infection
option 2: we could limit community transmission and ensure case rates remain very low until a vaccine is developed
option 3: we could push to completely eradicate the virus and avoid rebound when social distancing measures are relaxed, as long as borders remain closed
option 4: we could relax some measures and allow infection to continue in a very controlled manner, while protecting the vulnerable.
Each of these four approaches is associated with huge risks.
The first option would see a resurgence of the virus, with similar consequences to those of an unchecked epidemic.
The second option involves keeping case numbers to a trickle until a vaccine arrives – squashing the curve to a flat line but not eliminating transmission completely. This appears to be the path we are now pursuing, but it is not yet clear whether we will be able to reopen businesses, restaurants and even schools while still allowing low-level transmission to continue.
If we continue this path, we should recognise that some form of lockdown is likely. We could gradually release the brakes, but any suggestion of an upswing would be met with renewed suppression efforts. We could continually be putting out spot-fires and intermittently returning to strict lockdown until a vaccine arrives.
The third option involves an attempt to completely eradicate all circulating virus. Although we may be able to return to our previous lives, we would remain highly vulnerable to recurrence through importation if we were to reopen our borders.
If we were to pursue this path, extensive public engagement would be essential. We would need to remain in lockdown for many weeks after the last case has been reported and the rationale for pushing through towards eradication needs to be communicated clearly.
It is unclear if this is the strategy pursued by China, but its promising case numbers demonstrate the value of strict and prolonged lockdown. The rebound risk of this strategy will only be tested once strict lockdown measures are released.
The fourth option may include carefully controlled transmission of the SARS-CoV-2 virus in select low-risk groups, which is an extremely dangerous path.
However, the almost complete absence of mortality in children and young adults may allow us to consider ways by which we can increase population-wide immunity, while protecting the vulnerable to avoid the huge rates of death seen in the elderly.
The term “herd immunity” has generated considerable controversy since the start of this pandemic. But ensuring a significant proportion of the population develop natural immunity to the virus – in a controlled manner – could be the only way to slow its spread while returning to our previous lifestyles, in the absence of an effective vaccine.
We still need to understand better the risks posed to young people from natural infection, as well as the strength and duration of natural immunity. But current indications are the disease is relatively benign in healthy, young people and that they do acquire immunity. This very distinctive pattern may provide a key to coming out of lockdown while minimising risks – if an effective vaccine fails to materialise in the near future.
This option would need to be carefully controlled to ensure the virus cannot spread to the elderly and the vulnerable. How this could be achieved remains to be considered, but could involve the creation of environments in which transmission can be carefully facilitated among healthy young volunteers, without any risk of spread to the general community.
Natural immunity in a substantial proportion of the younger generation would allow those individuals to get on with their lives without putting others at risk. It would also slow any recurrent outbreaks that may occur once lockdown restrictions are relaxed.
Although there are no easy answers, we need to actively debate our exit strategy now, and collect the necessary information to guide our decision making. We may have to consider different solutions in different environments, but with an overarching strategy that is nationally coordinated.
Following the emergence and rapid spread of COVID-19, several countries have succeeded in bringing local outbreaks under control. The most dramatic of these is China, where large scale restrictions on people’s movement appear to have halted domestic transmission.
South Korea, Singapore and Taiwan also had early success containing local outbreaks, using a combination of extensive contact tracing, testing, border measures and differing degrees of social distancing.
However, COVID-19 is now widespread across the globe, and these countries remain at risk of a second wave of infections, sparked either by overseas arrivals or undetected pockets of infection.
Infectious diseases spread via contact between infectious and susceptible people. In the absence of any control measures, an outbreak will grow as long as the average number of people infected by each infectious person is greater than one.
If people who recover generate a protective immune response, the outbreak will leave a growing trail of immune people. Once enough people are immune, there are fewer susceptible people to become infected and the outbreak will die away.
When an outbreak is brought under control by social distancing and other measures, it’s possible only a small proportion of the population will have been infected and gained immunity.
If a population has not achieved herd immunity, enough susceptible people may remain to fuel a second wave if controls are relaxed and infection is reintroduced.
Will we see a second wave in China?
Despite the scale of the outbreak in Hubei and other Chinese provinces, it’s likely most residents remain susceptible to infection.
Even for those people previously infected, immunity to COVID-19 is an open question. Reinfection appears uncommon, and a study in rhesus macaques suggests a protective immune response does occur. But we need more data to understand if this is common in humans, and how long immunity might last.
The strong social distancing measures used to control COVID-19 in China have a human cost, and cannot be maintained indefinitely.
As China winds back social distancing measures, new infected cases could, if not quickly detected and isolated, trigger a second wave of COVID-19.
A recent modelling study indicated a second peak of infection might arrive in Wuhan by mid-year if interventions were lifted too quickly.
During the 1918 influenza pandemic, it was the second wave that was the largest and most deadly. But that probably won’t happen today. As we learn more about COVID-19, we become better placed to control its transmission.
If a rapid increase in transmission is detected in China, it’s likely authorities would quickly reintroduce the restrictions that successfully contained the first wave.
Preventing a second wave of COVID-19
When the first wave of an outbreak is sufficiently large, then enough of the population could become immune that there are too few susceptible people remaining to fuel a second wave. But the potential human cost of an uncontrolled outbreak is immense and unacceptable.
Alternatively, a globally coordinated response that eradicated the virus could prevent a second wave, as was achieved for SARS in 2003. However, the milder nature of many infections, and the broad global spread of COVID-19 make it a much greater challenge to eradicate.
We use mathematical models to explore the dynamic behaviour of infectious diseases. They can help explore how factors such as the strength and timing of control efforts might affect the likelihood and timing of a second wave.
However, models provide a simplified view of reality. One of the complexities they often (but not always) omit is human behaviour and how it might change in response to government and media communication, social and economic realities, and direct experience of COVID-19.
Australia’s current efforts are focused on “flattening the curve” of the first wave of COVID-19.
Border measures have greatly reduced the arrival of imported cases, and the coming weeks will reveal the extent to which social distancing measures have succeeded in slowing community transmission. The decline in numbers of new cases reported over recent days is promising.
But this is only the beginning. If social distancing measures are to be relaxed, ongoing vigilance will be needed to prevent a second wave.
Nic Geard, Senior Lecturer, School of Computing and Information Systems, University of Melbourne; Senior Research Fellow, Doherty Institute for Infection and Immunity, University of Melbourne and James Wood, Public health academic, UNSW