Coronavirus: We’re playing our part apart, and it’s helping slow the spread

Social distancing is working to flatten the curve, but medical experts say we can’t relax for many months yet.

People obey strict social-distancing rules while exercising near Bondi Beach in Sydney this week. Picture: Getty Images

There has been cause for significant hope this week in Australia’s battle against the coronavirus. The early signs are that not only is our epidemiological curve flattening, it’s looking like it may be reversing.

Yet still the Prime Minister is preparing the population for at least six months of a dramatically different way of life, with unprecedented government inter­vention in our social lives that curtail our civil liberties in a manner not seen in modern history.

So why, if the curve continues to flatten, will we need to live with these clampdowns for so long?

And what will happen when they are progressively relaxed?

Deputy Chief Medical Officer Paul Kelly was blunt this week in his assessment that COVID-19 would not be contained in Australia until a vaccine was available. That is, at the most optimistic estimates, at least 12 months away. So unless Australia is to again experience the exponential growth in infections that we were seeing a week ago, the only way of keeping a lid on the spread of the virus will be keeping people at a distance from one another, so that infected people have only a limited opportunity to spread the infection.

“This is going to be a prolonged period where we’re looking at ­having to keep these measures in place,” says Adam Kamradt-Scott, an associate professor at the University of Sydney. “The situation is still very serious, and although we are seeing some positive signs that our transmission rate may be decreasing, these measures will have to remain in place for the foreseeable future, until we see that transmission rate basically come down to zero.”

Infectious diseases physician Peter Collignon was upbeat about the trend in infections, which is being seen even before the impact of the reductions on gathering sizes, and gym and restaurant closures, are reflected in the data.

“We have more than just flattened the curve,” Collignon says. “We are reversing it. But until we have broad immunity from either a safe vaccine or from infection itself, we will continue to be at risk.”

Tom Kompas, a professor of biosecurity and environmental economics at the University of Melbourne, also describes the downturn in the curve of infections as pleasing.

“Although it is still too early to tell for sure, from the data that is available, it looks very promising,” Kompas says. “The daily growth rate in infections has been falling dramatically recently and is now less than 4 per cent. The same result holds if you take two- or three-day rolling averages.

“There were periods during much of March, with arrivals from overseas and other factors, where the daily growth rate was 24 per cent or more.

“Although, again, it is too early to tell, it does look as though voluntary and enforced physical distancing is having an effect.”

Despite the early trend, most experts believe the Prime Minister’s estimate that strict social-­distancing measures will need to remain in place for six months is roughly correct. But the time­frame will depend significantly on the level of adherence, says University of Sydney environmental virologist Hannah Sassi.

“There was a study recently out of the University of Sydney and they modelled and estimated that if 80 per cent of the population actually adhered to the strict social distancing, not interacting with each other, not hanging out, the epidemic would only last for a little over three months,” Sassi says.

“But as soon as that adherence drops down to 70 per cent, you see a massive extension in the rise in cases. If everyone adheres to the social distancing, then I think four months is probably a realistic time frame of how long the measures need to stay in place. If not, maybe six months or beyond.

“But I think we won’t know the peak until we’ve passed it. Because we’ll see a rapid increase and then we’ll start to see a decline, and that’s when we’ll know we’re past the peak.”

The bind for governments is the near certainty that once social-distancing measures are relaxed, the numbers of new infections will again begin to rise.

“I wouldn’t say it’s inevitable, but that seems likely if we transition out of control measures too quickly,” says Kompas. “It’s what one gets from the US data during the Spanish flu. Many cities experienced a second wave.

“Medical professionals tend to agree that you really don’t solve this problem, fundamentally, until you get a vaccine in place.”

A second-wave rise in numbers will be a lot easier to control as long as the borders remain shut, but the heavy impact on the economy could be prolonged well beyond a six-month timeframe, says Bruce Thompson, dean of health at Swinburne University.

“As long as you’ve got the ­active virus and it’s still active, and then you lift social distancing, then basically the virus can spread again,” Thompson says.

“The central issue is that this virus is going to be very difficult to manage until we have a vaccine. Certainly, it’s going to be very hard to open up our international borders until we have a vaccine.”

The management of the virus beyond six months will be a matter of closely watching the data once social distancing is progressively relaxed, says Hassan Vally, an ­epidemiologist at La Trobe University. “The worry is when people talk about an approach where you put the brakes on hard for a while and you reduce the spread, and then you see what happens as you relax the brakes — clearly, the possibility is that the rate of spread starts to increase,” Vally says.

“You may need to put the brakes on again if it starts to look like it’s spreading too fast. People have talked about pulses, a series of really hard pulses where you put the brakes on really hard and then you relax them to see the effects.”

One of the immediate dangers, however, will be a false sense of complacency among the population as the message starts to filter through that the curve is flattening.

“My concern at the moment, and this is a concern shared by many in this space, is that then people may start to think that they don’t need to comply with the ­social-distancing measures to the same level of stringency as what we’ve been encouraging them,” says Kamradt-Scott.

“They may think, ‘oh well, the worst is over’,” he says. “And what we have seen in a number of other countries is what’s described as a ‘hockey-stick effect’, whereby you end up with an initial downturn in the epidemiological curve followed by a sudden sharp increase in the number of cases.

“There’s still a very real risk and it is critical that people continue to maintain their social distance until the government says otherwise.”

Beyond the six-month time frame, once Australia’s social-­distancing measures begin to be relaxed, they will need to be relaxed progressively, Kamradt-Scott says.

Getting schools back to normal will be a high priority, he says, and the size of social gatherings may be able to be slowly increased from two back to 10.

However, larger events such as football matches will be difficult to envisage for at least a year, or perhaps until a vaccine is available.

Serological testing may hold some salvation in getting society back to normal functioning, says Sassi. Blood antibody tests are starting to come onto the market that determine whether an individual has been exposed to the virus, and therefore whether they have antibodies.

The pinprick blood tests would be significant because they’d be able to determine immunity in the high proportion of cases that had been exposed to the infection, but displayed no symptoms and had been unaware they’d contracted the disease.

The individuals who were shown to have immunity could get back to normal functioning without having to worry about social distancing, which would be crucial for health workers.

“It would be beneficial if we could have more large-scale testing, not just of those who are showing symptoms,” Sassi says.

“That would really help in knowing when to curb the social distancing. If we can test who has the antibodies, who’s been exposed, and we’re seeing a high number of people who have recovered and have antibodies, it would definitely help in getting a better estimate on who has been exposed to the virus and who has developed antibodies.”

For now, the next week will be crucial in determining whether the early signs of success in flattening the curve develop into a clear trend. Experts are optimistic that the population has heeded the call to stay at home, with the signs clear to see on the empty streets that this is indeed the case.

“Within the space of a week, I think we’ve seen the message really hit home and people have started to alter their behaviour as a result,” says Kamradt-Scott.

“That altered behaviour needs to be in place for the foreseeable future, before we start to even ­consider what measures might be lifted or relaxed.”