In the early stages of the Covid-19 pandemic our colleague Professor John Cherrie (Principal Scientist at Institute of Occupational Medicine) suggested a risk matrix illustrating control options for key workers arranged according to likely exposure would be a useful tool for occupational hygienists and others seeking to select and apply control measures in a manner proportionate to risk.
Given the reliance on respiratory protective equipment (RPE) in the early stages of the epidemic the BOHS Covid-19 RPE Working Group initially took up development of the matrix under the guidance of Professor Raymond Agius (Emeritus Professor of Occupational and Environmental Medicine at The University of Manchester). It was soon agreed that the risk matrix should reflect the control hierarchy and final development was undertaken by the BOHS Covid-19 Control Measures Working Group.
The risk matrix is by no means intended as the last word on this subject and we welcome further evidence to improve it which can be sent to firstname.lastname@example.org. We are of course conscious of the rapid progress in the science relating to the virus, its transmission and infectivity.
The Risk Matrix The matrix initially provides generic occupational descriptions sorted according to primitive factors that affect the level of risk (eg; public or non-public facing, chance of contact with infected individuals). The generic occupational descriptions are expanded into examples of occupational groups represented by each generic occupational description. At the outset, the occupational groups were selected to represent “key workers”, however the examples have been expanded somewhat to include groups such as nail bar workers.
It is hoped that the range of occupational groups selected will enable a reader to find a description analogous to their situation, should their specific occupational group not be explicitly described.
The “Exposure Rank” and “Control Band” elements of the risk matrix draw on work and a recent presentation by Lisa Brosseau, Professor (retired), Research Consultant, University of Minnesota Center for Infectious Disease Research and Policy, entitled “Infectious dose can it inform COVID -19 Decisions?”. The work gathers recent research relating to infectious dose and transmission to provide an approach to exposure ranking and control banding. We are grateful to Lisa Brosseau and colleagues for their contribution and also to John Dobbie (Group Industrial Hygiene Director -BP) for not only drawing this work to our attention but also providing a control options template and examples of it’s application in the workplace.