Director of the Victorian Infectious Diseases Reference Laboratory
The Doherty Institute for Infection and Immunity, Australia
What are you and your institution currently working on regarding COVID-19?
Our group is currently completing a project to develop and validate saliva-sample based surveillance using RT-PCR in asymptomatic subjects in high risk workplaces. Our aim was a solution that was simple and scalable, acceptable to users, using low cost sample collection consumables not threatened by supply chain disruptions, and sufficiently sensitive and specific for use in testing within a framework of regularly repeated sampling. We have compared feasibility and performance of saliva collection methods, and have validated the within-laboratory performance characteristics of the test using both panels of donor saliva spiked with cultured virus, and limited numbers of available paired saliva and respiratory swabs from SARS-CoV-2 infected subjects. Australia’s success in interrupting SARS-CoV-2 transmission has presented a challenge for assay validation; on balance a good problem to have. We get good results within the first week after symptoms, which makes the approach a good fit within a surveillance program of regular testing, but would not be optimal for general diagnostic use. We have done field trials of our sampling methods in several different groups of workers, totaling over 4000 subjects. We are currently completing work with several large Victorian diagnostic and hospital laboratories to have transferred testing capability to them, and to achieve the necessary Australian laboratory accreditation for the methodology, which we hope will happen in the coming weeks. A demonstration surveillance program incorporating our saliva protocol has gone live among selected at-risk workers during the first week of December, and is currently performing well.
Please describe your work with serological assays or diagnostics.
Our laboratory diagnosed Australia’s first case of COVID-19 disease in Melbourne on January 24, 2020 using in-house RT-PCR assays; confirming by nucleic acid sequencing through that night. Within the next few days we had cultured the infecting SARS COV-2 virus from the first Australian patient. This strain was rapidly shared within Australia and internationally with reference laboratories, researchers and culture collections.
Over subsequent weeks our laboratory supported other Australian states, and near-neighbor countries with interim diagnostic capacity, while assisting Australasian laboratories to establish diagnostic capability. Victorian public and private laboratories were also assisted to stand up their own SARS CoV-2 diagnostic capability over the following months, and supported with diagnostic services until this was achieved. During this period we were one of 15 international laboratories invited by WHO to form an expert laboratory network. Tasked by the Commonwealth Minister for Health with urgent development projects to assist Australia’s surge capacity, our laboratory developed protocols for pooled sample testing, and extraction-less RT-PCR testing. Through the months that followed we achieved diagnostic test surges of up to 3400 samples/day (350 x normal daily throughput), using sample pooling of a total of 29,000 samples to manage peak throughput. Less than 10% of Victoria’s daily SARS-CoV-2 testing is now done by our laboratory, but this has still amounted to over 200,000 RT-PCR results issued to date.
Our laboratory collaborated with Royal Melbourne Hospital on validation studies of serological test platforms, and used this data to build a serology diagnosis and confirmatory testing algorithm employing Spike protein IgG and IgA, and total antibody EIAs, surrogate neutralization (sVNT) EIA, and microneutralization assay. Testing of Victorian sera has subsequently been done as part of Australia’s first national SARS-C0V-2 sero-survey. The Doherty Institute public health laboratories have also collaborated to provide near real-time genomics data on more than 80% of Victorian laboratory-proven COVID-19 patients in support of the COVID-19 public health response.
Dr. Mike Catton is Director of the Victorian Infectious Diseases Reference Laboratory (VIDRL), and Co-Deputy Director of the Doherty Institute. He trained in microbiology, then medicine at the University of Otago in New Zealand, and received his Fellowship of the Royal College of Pathologists of Australasia (RCPA) in virology in 1992. He has been Director of VIDRL since 2001. His professional interests are in molecular viral diagnostics, high containment laboratory facilities and emerging viruses. He has served on diverse advisory committees related to public health and infectious diseases, to the Victorian and Australian governments, the RCPA, and WHO, and has consulted for WHO internationally. He was cofounder and founding Vice-President of the Association for Biosafety of Australia and New Zealand (ABSANZ). He currently serves on the advisory committee of the Victorian Donor Tissue Bank.