Undetected Omicron Transmission in Romania-Report of the First Detected Case of Locally Acquired Omicron Infection and Complete Epidemiological Investigation.

The occurrence of the omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has importantly impacted surveillance and diagnosis, and has changed the therapeutic landscape of coronavirus disease 2019 (COVID-19). We present the first documented case of locally acquired SARS-CoV-2 omicron variant in Romania in a patient with no recent travel outside the country. We also present the full results of the epidemiological investigation that led to the identification of the index case in a co-worker who had developed mild symptoms shortly after returning from the UK and who had undergone multiple rapid antigen tests with negative results prior to being tested by RT-PCR. We highlight potential lessons learned and describe further directions for actionable research and development in the field of COVID-19.