The COVID-19 infection cluster centred on the Cedar Meats processing facility ion Melbourne has proved to be one of Australia’s largest and most problematic. And the same situation has been experienced in meat processing facilities around the world, including in the US, Canada, Spain, Ireland and Brazil. A recent article, for example, identified that one of the fastest-growing outbreaks in Texas was associated with a meat processing facility in a small town in the north of the state.

So what is it about these facilities that create an environment ripe for the highly infectious virus to proliferate? It seems that the combination of proximity working, combined with frigid and humid conditions and a particular approach to ventilation is the most significant contributing factors. The suggestion is that in these conditions, the generally accepted social distancing norm of 1.5 to 1.8 metres is insufficient to prevent community transmission, precisely because of the nature of the ventilation.

This comes down to the nature of the virus particle and the way it spread. First, the cold, moist conditions allow it to persist for longer in the environment. Second, its minute size means that it is easily borne in the air, attached to droplets of water, in the form of aerosols (this is the health description of minute airborne pathogens such as viruses and bacteria). Finally, the intense ventilation that is required in these facilities to keep the meat fresh is responsible for moving the virus particles much further than the 1.5 to 1.8 metre recommended distance between workers.

It is already clear that socially enclosed spaces create ideal conditions for the spread of COVID-19 – in Australia, the other two significant sources of virus clusters have been cruise ships and aged care facilities, both of which share close interpersonal conditions and significant internal ventilation requirements. However, there are other forms of manufacturing and processing that involve people working in close proximity in enclosed, ventilated spaces.

As knowledge about COVID-19 continues to grow rapidly and businesses, public health authorities and governments attempt to identify mechanisms to prevent or reduce its spread, it is becoming clearer that high quality, well maintained and properly operated ventilation systems are essential. This will become increasingly important in Australia as social distancing and self-isolation requirements are eased, and people start returning to work in office environments in particular.

It will become increasingly important that shared workspaces, whether in manufacturing and processing, health care or office buildings, will require improved and updated ventilation systems that are capable of managing the risk to workers.

However, it is not feasible for all workplaces to immediately replace ventilations systems. In this instance, there are a number of recommendations and adjustments that can be made to existing systems to mitigate the risk of infection. These include:

• Increasing ventilation rates and increasing the proportion of outside air in ventilation exchange. This will help to ensure that air which potentially contains pathogenic aerosols is ejected faster, reducing the threat of infection.
• Increase the operating time of ventilation systems to include before and after normal business hours, and preferably through the night to ensure cleaner, unpolluted air is brought into the building.
• Have the ventilation system inspected by a professional service provider to ensure it is correctly set up, serviced and maintained, in line with the manufacturer’s requirements.
• Ensure filters are clean and, if required, consider the installation of higher grade filtering material.