SARS-CoV-2 screening in cancer outpatients during the second wave of the COVID-19 pandemic

The coronavirus disease 2019 (COVID-19) pandemic has caused a global health crisis and caused over 1,532,418 deaths worldwide until 7 December 2020 [1]. Oncology patients were repetitively reported to be at a particular risk with fatality rates of up to 11.4% [2‐4]. Potential factors contributing to the higher risk for adverse COVID-19 courses among cancer patients include the high average age, high rate of comorbidities, disease-associated and therapy-induced immunosuppression and unavoidable social contacts during regular therapy and follow-up visits at the hospital [5]; however, besides direct endangerment of cancer patients by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, concerns about adverse outcomes associated with disruptions in oncological care due to COVID-19 have emerged [6, 7]. Therefore, continued administration of anti-cancer therapies has been defined as a priority by oncological societies and cancer centers around the world [8, 9].

At our large tertiary care center of medical oncology with approximately 40,000 patient contacts per year, we have rapidly implemented strict safety measures during the first wave of the COVID-19 pandemic in Spring 2020. We could show that these safety precautions resulted in low rates of detectable SARS-CoV‑2 infections among our patients and anti-SARS-CoV‑2 antibodies among our patients and staff that allowed continued patient care and therapy at our center [10, 11].

The second wave of the COVID-19 pandemic in the fall of 2020 hit Austria particularly hard as Austria was among the countries with the highest 7‑day incidence rates worldwide with 565 new infections per 100,000 on 12 November 2020 [12]. In order to protect the well-being of our patients and staff as well as the functionality of our clinical service, we implemented strict safety measures during the second wave based on our experience during the first wave. Although many institutions refrained from regular SARS-CoV‑2 testing of patients owing to logistic restraints, the safety measures implemented at our institution included a recommendation for biweekly testing of all patients for SARS-CoV‑2 RNA using nasopharyngeal swabs and polymerase chain reaction (PCR).

Here, we analyzed performance parameters of this SARS-CoV‑2 screening program at our center during the second wave. We aim to provide an information basis for optimization of standard operating procedures and resource allocation for crisis response during potential subsequent infection waves of the COVID-19 pandemic.

This study was approved by the ethics committee of the Medical University of Vienna (vote number 2485 of 2020).

SARS-CoV‑2 testing is essential to prevent viral transmission and curb the on-going pandemic by early identification and isolation of infected individuals. Due to the incubation period of 3–6 days, asymptomatic virus carriers are major contributors to the overall viral spread, particularly in the setting of healthcare facilities [19‐22]. Consequently, focused testing in healthcare facilities is recommended to prevent nosocomial COVID-19 infections and maximize safety of patients and staff [19]. In the present data we observed comparable increases in SARS-CoV‑2 infections in the cancer cohort as in the general Austrian population. We achieved a 68.4% testing coverage of cancer outpatients treated at our department during the second wave of the COVID-19 pandemic between October 1st and November 30th using an institutional policy recommending biweekly SARS-CoV‑2 testing. Our strategy is based on our previously reported experience [10] and differs from other centers that perform SARS-CoV‑2 testing only in selected patients [21, 23‐25].

Overall, our data indicate that routine PCR-based testing is feasible at a large department of medical oncology with over 3000 patient contacts per month; however, perfect test coverage was not achieved, leading to a projected number of five undetected virus carriers at our department during the observation period. We report that clinical patient parameters apparently influenced SARS-CoV‑2 testing rate in cancer in a high-volume setting. We believe that our data may be useful for adaptation of standard operating procedures and resource allocation in order to optimize protective measures during potential subsequent infection waves of the COVID-19 pandemic.

Patients currently not under active antineoplastic treatment and patients with a lower number of visits were less likely to undergo SARS-CoV‑2 testing. The experience gathered during the observation period indicates that logistical challenges are main contributors to limiting full test coverage of all patients. The infrastructure of our institution did not allow for direct easy access testing during patient presentation at our department but necessitated the referral of patients to a central SARS-CoV‑2 testing unit that services the entire hospital. The implementation of a central testing unit allows efficient resource allocation and standardized testing at a large center; however, it increases the complexity of patient administration for staff members and the number of in-hospital transits and waiting times for individual patients. These factors likely have contributed to our results and need to be taken into account for informed application of safety measures to contain viral spread. As a consequence of our data, we advocate routine extramural testing of patients not undergoing active anticancer therapy just before presentation to a tertiary care oncology service, e.g. at general practitioners or testing facilities for the general public. In-hospital testing should be reserved for patients undergoing active anticancer therapy in order to achieve focused resource allocation. This measure should be suitable to avoid underdetection of SARS-CoV‑2 positive patients in the vulnerable medical oncology center and thus increase patient and staff safety [26].