Many companies and institutions are currently facing the challenge of having to monitor larger groups of people for Covid-19, while lacking the personnel or infrastructure to do so. This challenge is particularly urgent in retirement and nursing homes, where employees pose a great risk of carrying SARS-CoV-2.
A team of scientists around Johannes Zuber from the Research Institute of Molecular Pathology (IMP) at the Vienna BioCenter has been working on a concept for routine monitoring of such groups of people since April. The work, conducted in the frame of the in the frame of the "Vienna Covid-19 Detection Initiative" (VCDI), gave rise to a standard operating procedure: after taking a sample by gargling, an RT-qPCR test is carried out and the result is made available to the tested person within hours.
After the first test of a monitoring scheme with volunteers at the Vienna BioCenter, a pilot project followed in cooperation with Caritas nursing homes in Vienna and Lower Austria. In addition to Caritas of the Archdiocese of Vienna and the Vienna BioCenter scientists, the non-profit organisation Novid20 also played a major role in the project, contributing innovative solutions for sample logistics and data processing.
Standard procedure showing the way forward
Since mid-October, almost 1,000 employees have been tested for SARS-CoV-2 twice a week. The pilot project will soon to be extended to 17 homes with almost 2,000 Caritas employees. In practice, the optimisation of logistics and speed proved to be particularly important, with pooling and efficient data transmission playing key roles.
"On test days, the employees gargle at home in the morning and fill the gargle liquid into two plastic tubes - the pool sample and the retention sample, which they both take with them to the workplace," Johannes Zuber explains the concept, "The pool samples are then grouped in such a way that they represent teams of people who are also in close contact in everyday work. These samples are then mixed."
This pooling can take place both at the workplace or in the laboratory, provided that adequate hygiene regulations are observed. The pools of all teams are then assessed for genetic traces of the SARS-CoV-2 virus using a very sensitive PCR test. If a pool is positive, reserve samples from all the people in the pool are analysed individually to identify the carrier of the virus and to inform him or her immediately. People who test positive can stay at home the very next day and call the national Covid-hotline 1450 to undergo a medical, diagnostic test.
Data from the pilot project
The first extension of the pilot project with Caritas nursing and retirement homes showed the urgency of efficient monitoring: 2.6 percent of the people tested showed positive results during the course of the study, but were asymptomatic at the time the sample was taken - this means that without the test, these people would not have isolated themselves and might have infected residents with SARS-CoV-2.
The pilot project as part of the university funding made available by the Federal Ministry of Education, Science and Research (BMBWF) and Caritas of the Archdiocese of Vienna. The development of new test methods is additionally supported by the Vienna Science, Research and Technology Fund (WWTF).
Vienna Covid-19 Detection Initiative of Vienna BioCenter and University of Vienna: https://www.viennabiocenter.org/vienna-covid-19-detection-initiative/
More on VCDI: https://www.maxperutzlabs.ac.at/vcdi
Scheme for the "Monitoring Pipeline": https://www.maxperutzlabs.ac.at/vcdi/vcdi-news/sop