# Clinical and molecular fingerprint of SARS-CoV-2 among hospital employees in a period of Omicron BA.2 dominance

## TL;DR

This study examines SARS-CoV-2 infection patterns among hospital staff during the Omicron BA.2 wave, finding that asymptomatic testing and early clearance testing are ineffective.

## Contribution

The study challenges the effectiveness of routine asymptomatic testing and early post-recovery clearance testing for SARS-CoV-2.

## Key findings

- No correlation was found between PCR results and testing time or frequency in asymptomatic contacts.
- A high correlation was observed between positive antigen self-tests and positive PCR tests.
- Clearance testing before day 8 after recovery is not appropriate.

## Abstract

In the spring of 2022, SARS-CoV-2 Omicron BA.2 peaked in Germany. The main burden was staff shortage. To achieve effective identification and management of infected persons as well as early reintegration of recovered persons, an infection-control outpatient clinic was established at the Bundeswehr Central Hospital Koblenz. This article reports a secondary data analysis of 663 people with 1,174 visits to the outpatient clinic. For asymptomatic contacts, no correlation was observed between PCR result and testing time or frequency. Although no significant symptoms were documented, a high correlation was found between a positive antigen self-test and positive PCR. For clearance, a median time until a negative test was obtained was 8–11 days. The PCR gold standard was compared with ECLIA antigen testing for all indications. The results of this study challenge the rationale for testing asymptomatic contacts. Solely symptom-driven diagnostics by PCR also do not seem to be effective. However, contact persons or symptomatic persons with a positive rapid antigen test should be tested further. Whether this testing is done by ECLIA or PCR does not seem to matter. Clearance testing after recovery prior to day 8 is also not appropriate.