How Labour Day weekend changed Victoria’s virus fight

reproduced article written by Grant McArthur, Health Editor, Herald Sun,  Published Herald Sun, April 11th 2020

As Department of Health contact tracers painstakingly investigate each COVID-19 case back to its source to get one step ahead of where it will spread, recalling the Labour Day long weekend sends shivers down the spines of those charged with trying to control the virus.



Among the dozens of places visited by one of Victoria’s latest COVID-19 patients, one venue sticks out. Contact-tracing investigators interviewed others with confirmed coronavirus who reported being at the same place on the same night — but they attended a different function. As they compared the cases searching for a connection, no obvious source for the infections jumped out because no guests attended both events. Another COVID-19 patient emerged and recalled attending yet another gathering at the same venue days later, but further interviews struggled to nail down any person that all the sick had in common. Then, a check of the staff on duty threw up a match at all three events and a new possibility — does Melbourne have a super-spreader? “He worked in a hospitality venue. Initially we thought there was a cluster of cases who had all been to that venue on a particular night and we thought somebody in that place had it,” said Victoria’s Deputy Chief Health Officer, Dr Annaliese van Diemen. “A bit later there was another cluster from an event at the same place. “Now there are at least three clusters linked to that venue, and at least one of them has seeded off another.” Although the worker never had strong symptoms, tests confirmed he had COVID-19. “It is becoming clearer that some people are more infectious than others for reasons we are not certain of yet,” Dr van Diemen said. “We have seen it in SARS and MERS as well — this is a virus that has the capacity in some people, even though they are not hugely sick, to spread it to a lot of people.” With so much unknown about COVID-19, the work of Department of Health contact tracers to painstakingly investigate every case back to its source is the only way of getting one step ahead of where it may spread to. Each case may require hours of interviews, producing scores of leads which need analysis and cross-referencing. This can result in dozens of the patients’ loved ones, friends and colleagues ordered into self-isolation. Dr van Diemen knows getting a step ahead of each cluster is all that stops COVID-19 surging through Victoria. “At the moment we have 52 clusters — that is how many we are trying to keep track of,” she said. Until then, the disease that had devastated parts of China and was threatening Europe had barely made its presence felt in Victoria. “All of February was quite quiet, before the March long weekend which will be etched in all of our brains forever,” Dr van Diemen said. “That was case 11, which was just over a month ago — now we are past case 1000.” The turning point was the case of Toorak GP Dr Chris Higgins, who returned from the US before it was classified as a major coronavirus zone. Suddenly Victoria’s team of 30 contact-tracing specialists had to find and interview more than 70 of his patients, place each one in isolation and investigate whether they had spread the virus further. Thankfully, there were no further cases linked to Dr Higgins or the Toorak clinic. But as the weekend progressed, more cases flowed in from other US travellers, and every epidemiologist’s worst fears were realised. “That weekend we had a couple more cases dripping through and we thought, ‘OK, we are going to need a bit more space than what we have now’, so we expanded to this room on the Monday,” Dr van Diemen said. “By the end of that week we had already run out of room, so we had to expand to different locations.”

THE CAVALRY ARRIVES
It’s now just four weeks later, but the team of 30 has grown to 1000. They fill floors 1, 13, 14, 15, and 18 of the Department of Health tower at 50 Lonsdale St. Those who can’t fit there have taken over the offices of a nearby travel agency. Others who have contact with patients must work from home so they don’t risk infecting the COVID HQ. Of all the staff working hard when the Herald Sun visits, a dozen stand out. Wearing military fatigues, 12 members of the Australian Defence Force have been deployed to “floor-manage” the teams of nurses, doctors and public health bureaucrats. Next week the military presence is expected to multiply, but the sight of camouflage in the corridors barely raises an eyebrow now. The sheer number of patients and speed at which COVID-19 spreads means the investigators have had to change everything they do. In the case of common outbreaks such as measles, the flu or salmonella, a specialist investigator follows each case from start to finish. Since last month, COVID-19 investigations have become a production line of testing, interviewing, contact tracing, isolation measures and recovery. Less experienced nurses and others drafted in oversee the initial stages, and cases are passed up the line as they become more complex. “Because we now have so many cases — 50, 60, 80, 100 cases a day — we have had to separate the tasks that would normally be done,” Dr van Diemen said. “Every now and then, we sit down and say, ‘The stuff we’re doing in a 12 to 24-hour cycle would normally take months’.” The State Emergency Management Centre on level 1 looks like NASA’s mission control. Facing a wall of huge screens, rows of desks house the heads of each arm of Victoria’s COVID command who receive updates from investigators scattered on other floors, in hospitals or at coronavirus testing centres. At midnight, the team takes stock of the day’s new confirmed cases and prepares the data to be “cleaned” between 5-7am so the updated infection and death totals can be released to the public. Some days’ totals are much higher than others. The grim findings inform Chief Health Officer Brett Sutton’s recommendations, which in turn prompt the increasingly strict border and social distancing controls. Among the worst days for Victoria so far were March 14, 17 and 20, when investigators kept uncovering patterns of new cases linked to large gatherings. One cluster stemmed from a wedding attended by almost 300 guests and staff, including family members who flew in from overseas and are thought to have brought coronavirus with them. Eight guests became sick and tested positive after the celebration, while others were infected during post-wedding family visits. “Everyone at that wedding is being considered a close contact. They have all been isolated,” Dr van Diemen said. A guest flying to Australia for another wedding happened to share the flight with a person already suffering coronavirus, gaining the infection in time to attend the nuptials. Another cluster was born. Another two people became ill following a third wedding, though the timing of their illness suggests they caught coronavirus off another guest rather than introduced it. On March 25, weddings were limited to five people, while funerals were allowed just 10 mourners. As a COVID-19 tests comes back positive, the results are sent to the contact-tracing team and an investigation is launched. The first job is to uncover how they caught COVID-19. Once the source is established, investigators pore through everything the patient has done since, identify everyone they have been in contact with, and search for any possibility the virus may have spread further. The best-case scenario is that new cases can be linked to others already identified, and the people around the cluster are isolated to stop it running away. But when the painstaking analysis cannot uncover a clear source, the Victorian unit adopts the most conservative approach — closely monitoring locations the patient has visited for any further cases. Investigators can only let close contacts know where and when they came into contact with an infectious person, not who the carrier was.

But team leader Rebecca Shack [i.e. Schack] said 90 per cent had already been told by the carrier, and had been accepting of the news. “Some people aren’t too happy, some people are OK if they are friends, but there have been a few instances where people are incensed if they are not too close to them (the carrier),” she said. In the early days of COVID-19, international travellers wandering unrestricted through Victoria made tracing a nightmare, with dozens of leads and close contacts in each case. Travel bans and social distancing mean most cases now have only a few contacts of concern. Some have none. After seeing the chaos overseas, Ms Shack [i.e. Schack] said Victorians were now more understanding of the vital interview and isolation process. “There are still a few people who are angry, but the messages have been a bit nicer in the past couple of weeks,” she said. “But if you look at Australia’s numbers compared to other countries, they should think themselves lucky we are doing this.”
NEW EVIDENCE
Some patients have had very mild hay fever-like symptoms that disappear for days before re-emerging as COVID-19. Investigations into some clusters have now had to be reopened to trace back further than the days where it was previously accepted a person was infectious. “The trickiest bit at the moment is figuring out when they got sick,” Dr van Diemen said. “We have to be very careful about everybody maintaining physical distancing until we can work out more about this illness.” But the hard work is now paying off. With a drop in cases, the contact-tracing team this week celebrated a milestone — the median time from a patient’s onset of symptoms to home isolation was zero days. The less time an infected person is in the community, the fewer clusters contact tracers have to cut off. “The shutting down of international travel, the stay-at-home stuff, that is what has driven this down,” Dr van Diemen said. “We were on a trajectory with England two weeks ago. We were quadrupling every week. Now there is a palpable ‘maybe we can do this’ mood.”