Western Australians can be reassured that a confirmed case of COVID-19 in a mining worker, following a blood test performed by Mining Company Rio Tinto, is not cause for alarm and should not be interpreted as potential community transmission.
Western Australia’s Chief Health Officer, Dr Andrew Robertson, said the case was one of only three being reported in WA overnight, with the other two linked to the cruise ship Artania.
Dr Robertson said the Department of Health was investigating the case and undertaking appropriate contact tracing but that there was no evidence of community transmission resulting from this case.
Dr Robertson said the case had become mildly symptomatic shortly after returning from a trip to Indonesia which would indicate he most likely contracted the virus overseas. He was in isolation for the period in which he would have been infectious.
Dr Robertson said the pin-prick test performed by Rio Tinto was not an acute diagnostic test or even a reliable means of screening for current COVID-19 infection.
He said the reason point-of-care testing had been banned as an acute diagnostic test under emergency provisions of the Public Health Act was because it measured the presence of antibodies to COVID-19 – not the virus itself. This could lead to results being misinterpreted, with both false negatives and false positives being common, as demonstrated by recent such testing.
Dr Robertson said public health officials were currently working to verify the results of the individual at an accredited laboratory because the validity of the point-of-care test was unknown.
He said the pharyngeal nasal swab tests, being performed at COVID-19 clinics and authorised private pathology providers, still provided the most accurate form of testing and that following the recent broadening of testing criteria would ensure the best detection of community transmission.
Under the expanded criteria anybody who has a fever, history of fever or flu-like symptoms can be tested.