Asymptomatic detection of COVID-19 among cancer patients receiving infusional anti-cancer therapy

Introduction Little is known about the rates of asymptomatic COVID-19 carriers among cancer patients. The rate of asymptomatic carriers is important to understand in this population given the use of myelosuppressive and immunomodulating therapies and the risk of transmission to other patients in shared infusion centers. At UC San Diego, in June 2020, we implemented a COVID-19 asymptomatic screening protocol in which cancer patients receiving anti-cancer therapy in an infusion center must undergo symptom-based screening and then SARS-CoV-2 PCR testing prior to their infusion. Here, we describe the results of this asymptomatic screening protocol. Methods This was a single-center retrospective analysis of patients with active cancer receiving infusional anti-cancer therapy in 5 infusion centers who underwent at least 1 asymptomatic SARS-CoV-2 PCR test between 6/1- 12/1/2020. The primary endpoint was the rate of COVID-19 positivity among asymptomatic patients. Symptomatic patients were excluded. Secondary endpoints included COVID-19-related outcomes and patterns of oncologic management for asymptomatic COVID-19 positive patients. Results A cohort of 2,202 cancer patients received at least 1 asymptomatic SARS-CoV-2 PCR test prior to receipt of infusional anti-cancer therapy. 0.95% (N=21/2202) of patients were found to be PCR-positive on asymptomatic screening. Among positive patients, 9.5% (N=2/21) had hematologic malignancies and 90.5% (N=19/21) had solid tumors. In terms of therapy, 76.2% (N=16) were treated with cytotoxic chemotherapy, 9.5% (N=2) with targeted therapy, 4.7% (N=1) with immunotherapy, and 9.5% (N=2) were on a clinical trial. With a median follow-up of 122 days from positive PCR test (range: 8-186), only 2 of 21 (9.5%) of the cohort ultimately developed COVID-related symptoms. Both patients had a diagnosis of acute leukemia and 1 patient required hospitalization for COVID-related complications. No patients died from COVID-related complications. With regards to oncologic management, 95.2% (N=20/21) of patients had their therapy delayed or deferred with a median delay of 21 days (range: 7- 77 days). Only 1 patient proceeded with cytotoxic chemotherapy on schedule in the setting of adjuvant chemoradiation for oropharyngeal squamous cell carcinoma. Among the overall cohort, an additional 26 patients (1.2%) developed cases of symptomatic COVID-19 infection during the study period. Conclusions A strategy of asymptomatic screening of cancer patients receiving anti-cancer therapy in an infusion center detected an extremely low rate of asymptomatic carriers of COVID-19. This low rate of asymptomatic carriers may be due to a number of factors including multiple symptom-based screenings prior to infusion, behavior modification among patients, and/or differential immune responses to COVID-19 infection. Asymptomatic carriers in this cohort appeared to have favorable outcomes with few developing symptoms or requiring hospitalization, though the number of positive patients in our cohort is low, precluding definitive conclusions in this population.

Assessing Past vs Present COVID-19 Infection: A Survey of Criteria for Discontinuing Precautions in Asymptomatic Patients

Background. COVID-19 patients can remain positive by PCR-testing for several months. Pre-admission or pre-procedure testing can identify recovered asymptomatic patients who may no longer be contagious but would require precautions according to current CDC recommendations (10 days). This can result in unintended consequences, including procedure delays or transfer to appropriate care (e.g., psychiatric or post-trauma patients requiring admission to COVID-19 units instead of psychiatric or rehabilitation facilities, respectively). Methods. We conducted a structured survey of healthcare epidemiologists and infection prevention experts from the SHEA Research Network between March-April, 2021. The 14-question survey, presented a series of COVID-19 PCR+ asymptomatic patient case scenarios and asked respondents if (1) they would consider the case recovered and not infectious, (2) if they have cleared precautions in such cases, and if so, (3) how many transmission events occurred after discontinuing precautions. The survey used one or a combination of 5 criteria: history of COVID-19 symptoms, history of exposure to a household member with COVID-19, COVID-19 PCR cycle threshold (CT), and IgG serology. Percentages were calculated among respondents for each question. Results. Among 60 respondents, 56 (93%) were physicians, 51 (86%) were hospital epidemiologists, and 46 (77%) had >10y infection prevention experience. They represented facilities that cumulatively cared for >29,000 COVID-19 cases;46 (77%) were academic, and 42 (69%) were large ( >400 beds). One-third to one-half would consider an incidentally found PCR+ case as recovered based on solo criteria, particularly those with two consecutive high CTs or COVID IgG positivity recovered (53-55%) (Table 1). When combining two criteria, half to four-fifths of respondents deemed PCR+ cases to be recovered (Table 2). Half of those had used those criteria to clear precautions (45-64%) and few to none experienced a subsequent transmission event resulting from clearance. Conclusion. The majority of healthcare epidemiologists consider a combination of clinical and diagnostic criteria as recovered and many have used these to clear precautions without high numbers of transmission.

Infection with coronavirus disease 19 (COVID-19) in healthcare personnel with exposure to COVID-19

Background: As of June 2, 2020, 67,113 cases and 321 deaths due to Coronavirus Disease 19 (COVID-19) have been reported in healthcare personnel (HCP) in the United States. Given the close contact of HCP with individuals with COVID-19, it is important to quantify the risk of acquiring COVID-19 in the healthcare setting. Methods: We conducted a retrospective cohort study of HCP exposed to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at our academic medical center from March 15, 2020 to May 16, 2020. Exposure during the study period was defined as having contact with patients or other HCP with COVID-19 within 6 feet of distance for at least 90 seconds when HCP's eyes, nose, or mouth were not covered. HCP with exposures were monitored for symptoms consistent with COVID-19 for 14 days from last exposure and those who developed symptoms were tested for SARSCoV- 2 using RT-PCR. Results: We identified 33 exposure events;19 of which were patient-to-HCP exposures and 14 of which were HCP-to-HCP exposures. These 33 events resulted in 959 exposed HCP among whom 238 (25%) developed one or more symptoms of COVID-19 and required SARS-CoV-2 RT-PCR testing. Testing was performed at 7.1 ± 5.0 (mean ± SD) days from exposure. Of the 238 HCP who were tested, 82% were female and 49% were registered nurses (Table 1). Five HCP tested positive for SARSCoV- 2 by RT-PCR, but one was presumed to have acquired the disease from a household member with confirmed COVID-19. Among the four HCP who were infected due to occupational exposure, three were nurses while one was an environmental service worker (Table 1). Conclusion: Despite exposures among HCP, the risk of acquiring symptomatic COVID-19 in the healthcare setting was low with less than 1% of HCP with occupational exposure subsequently diagnosed with COVID-19. With the definition of exposure now changed to at least 15 minutes of close contact without personal protective equipment, we anticipate fewer exposures at our healthcare facility and that much of COVID-19 transmission affecting HCP are due to community exposures.

Asymptomatic healthcare worker COVID-19 testing program

Background: The SARS-CoV-2 pandemic remains a major threat worldwide. Healthcare workers (HCWs) are particularly impacted by the COVID-19 pandemic with high infection rates reported from HCWs in hard-hit regions2,3, raising concerns about nosocomial infections and the effectiveness of personal protective equipment in protecting HCWs. Asymptomatic infection is estimated 17.9% to 33.3%4 and is a common source of transmission5. We designed a HCW testing program to address patient and employee concerns about exposures in the healthcare setting at our 808-bed health system. During the time of employee testing, the mean (range) number of inpatients with a diagnosis of COVID was 30 (22-38) of a mean (range) daily census of 560 (492-602) (approximately 5.4%). Methods: This opt-in program offered SARS-CoV-2 testing of asymptomatic HCWs with paired nasopharyngeal or mid-turbinate swab for PCR (Roche) and serum IgG antibody testing (Diazyme). While initially designed as a pilot project in the Emergency Departments and COVID-19 units, it was quickly expanded to a health system-wide initiative. Results: From April 22 to June 2, PCR testing was performed on 5826 asymptomatic HCWs with four PCR tests resulting positive (0.09%). Of 5589 serologic tests (anti-SARS-CoV-2 IgG) performed, 57 tested positive (1.02 %). All HCW with a positive IgG had a concurrent negative PCR. Conclusion: In this cross-sectional evaluation, the point prevalence of SARS-CoV-2 IgG in asymptomatic HCWs at UC San Diego was less than 1%, supporting modeling estimations at the San Diego County level of very low levels of community exposure at the time of this testing. Further analyses of incidence rates and potential risk factors such as employee roles within the healthcare system, community and healthcare exposures, and home zip code are underway. Asymptomatic HCW testing is a strategy that can provide the perception of additional safety to both the workforce and patients as the health system reopens, while potentially reduce transmission from asymptomatic persons through active case finding and isolation.

Complication with bacterial pneumonia in hospitalized patients with coronavirus disease 2019 (COVID-19)

Background: Early reports have indicated widespread empiric antimicrobial usage in patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). As data regarding bacterial complications in patients with Coronavirus Disease 2019 (COVID-19) are limited and emerging, it is important to delineate the burden of complications with bacterial pneumonia in patients with COVID-19 and its implication on antimicrobial usage. Methods: We conducted a retrospective cohort study of all hospitalized patients diagnosed with COVID-19 based on detection of SARS-CoV-2 on RT-PCR from March 1, 2020 to May 10, 2020. Data were collected retrospectively to determine the presence of bacterial pneumonia among patients hospitalized with COVID-19 and to identify demographics, comorbidities, or laboratory values that may help to distinguish patients with bacterial pneumonia. Fisher's exact test was used to analyze categorical data and Student's t test was used to analyze differences between means. Results: Among 99 patients hospitalized with COVID-19 during the study period, complication with bacterial pneumonia was seen in 17 (17%) based on sputum, tracheal aspirate or lower respiratory tract cultures performed 8.9 ± 7.8 (mean ± SD) days from the detection of SARS-CoV-2 on RT-PCR. Staphylococcus aureus was the causative organism in 8 (47%) cases while Enterobacteriaceae were isolated in 7 (41%) cases, Burkholderia cepacia in one (6%) and Rahnella aqualitis in one (6%) case. There were no significant differences in demographics, comorbidities, or laboratory findings between patients with or without complication with bacterial pneumonia. However, those with complication with bacterial pneumonia were more likely to be intubated (24% vs. 88%, p< 0.01), on vasopressors (23% vs. 82%, p < 0.01), and require intensive care unit admission (37% vs. 94%, p< 0.01). Conclusion: Nosocomial and ventilator-associated pneumonia were commonly seen among hospitalized patients with COVID-19 requiring intubation and intensive care use admission. With complications of bacterial pneumonia common among critically-ill patients infected with SARS-CoV-2, widespread antimicrobial usage may increase the selective pressure for antibiotic resistance in this patient population.