In early 2020 during Victoria’s first wave, just one healthcare worker caught COVID-19 on the job in all of Western Health, a group of public hospitals, day hospitals and community-based health services in western Melbourne.
This nurse had cared for an abattoir worker who’d come in with a workplace injury and later tested positive for coronavirus, before the Cedar Meats outbreak was understood. No one else who was involved in the man’s care was infected.
Fast forward to the second wave, and 3,573 Victorian healthcare workers caught COVID-19, more than 7 in 10 of them at work.
While it makes sense that someone working directly with sick people has a higher than average chance of getting infected themselves, good infection control should have been able to keep this number much lower.
So what went differently in the second wave, and what lessons can we learn from it?
Geriatric care an unexpected hotspot
Marion Kainer, head of infectious diseases at Western Health, has been investigating this and presented her findings at the Australasian COVID-19 Conference yesterday.
Unsurprisingly, she found more than one factor at play. But a big contributor was that the virus got into the aged care sector, and then into hospitals via geriatric wards.
Most of the healthcare workers who got COVID-19 were nurses, or aged care or disability workers. Of the nurses, around 40 per cent caught it in an aged care setting.
Dr Kainer says the focus early in the pandemic had been on intensively training staff in emergency departments, intensive care units and COVID wards.
“One of the big surprises was the place which was really at very high risk were our geriatric wards,” she tells Coronacast.
These wards were receiving patients from residential aged care facilities, where, similarly to the case of the abattoir worker from the first wave, COVID-19 outbreaks were brewing but not yet known about.
“The patients were admitted without any respiratory symptoms and they were incubating coronavirus during that time period and then would infect our staff.”
But the fact they came from aged care carried an additional risk.
“Outside the health care setting, we know that choirs, churches where people are singing, shouting — that these can be super-spreading events. But these had not really been described in the literature or in the WHO guidance that this could be a risk factor within a hospital.”
Dr Kainer says experts assumed that the ventilation in hospitals would be good enough to take care of it, but it wasn’t.
Single-bed rooms were at a premium, so hospital workers grouped COVID patients together in four-bed hospital rooms.
“But I was really surprised to see that the design of these four-bed rooms was such that there was no air register to take the air out of that room. But the air would move actually into the corridor when the door was opened or closed.”
How much of a problem was PPE?
One of the big criticisms of the system during the outbreak was that healthcare staff didn’t have access to adequate personal protective equipment (PPE).
But Dr Kainer says early on, the issue was more that geriatric wards weren’t considered high risk environments warranting the use of N95/P2 masks, and staff wore surgical masks.
Compounding that was the fact that staff who worked with older patients weren’t practised in how to safely remove their PPE.
“We need to really make sure that everybody knows how to remove the personal protective equipment carefully so that they don’t contaminate themselves and that they are not rushed in this.
Dr Kainer says the experience has taught them that it’s not enough to only do infection control training for staff in emergency departments, intensive care units and COVID wards. Hospital airflow design needs to be reassessed too.
“We need to look carefully at the direction of airflow, as well as the number of [air] exchanges and take that into account in the design of new facilities and also explore mitigating strategies for existing infrastructure.
“For example, looking at portable HEPA filters or air scrubbers to assist with clearing some of those aerosols.”
Contract tracing forwards and backwards
Swift and thorough contact tracing is also essential to stop chains of transmission, Dr Kainer says — and it has to work in both directions.
You need forward contact tracing, which identifies people the newly positive case has been in touch with, to let them know they may have been exposed.
This is particularly important for household members who may also work in high-risk settings like hospitals, residential aged care facilities or abattoirs.
But acquisition tracing and testing — figuring out where the person caught the virus in the first place — is also really important, even though historically it’s not always been performed. This can help flush out extra cases that might not have otherwise been identified.
“It’s critically important that just like outside [healthcare settings], that we do this thoroughly and rapidly because there is so much patient movement that occurs within the hospital. If you don’t ring-fence that, you could easily have spread going from ward to ward to ward.”