Forty soldiers of the Austrian Armed Forces have been supporting AGES in the source search for COVID-19 infections since 16.11.2020. Divided into duty shifts, 20 soldiers and one team leader are on duty in each of three rooms. Each room is spaced two meters apart, ventilation is provided regularly, and air purification equipment is used. To prevent a COVID-19 outbreak within the source tracer team, all team members (Bundesheer and AGES staff) are offered testing by antigen test once a week.

In the first weeks, sampling was performed by means of deep, nasopharyngeal swabs by healthcare professionals. Since 12/17/2020, sample collection was by self-swabbing of the nasal entrance area.

For the deep, nasopharyngeal swabs, one test yielded a positive result, but this could not be confirmed by PCR testing and was considered false-positive. Of the antigen tests from swabs of the nasal inlet region, one test yielded a positive result, which could also be confirmed by PCR and was thus seen as correct-positive. In the course, all persons from the same room were tested by PCR, no infection could be detected. By quickly isolating the person in question, it was thus possible to avoid infecting other members of the source tracing team.

We see the possibility of antigen testing by self-sampling in the anterior nasal region as a low-threshold alternative to deep, nasopharyngeal swabs by healthcare professionals. The advantages of being able to immediately isolate potentially infectious individuals outweigh the lower sensitivity in our view.