Asymptomatic COVID in healthcare workers points to risk of silent spread
A study released this week shows a 40% asymptomatic rate among healthcare workers (HCW) testing positive for SARS-CoV-2 at the time of screening—meaning they had no symptoms compatible with a COVID-19 diagnosis—raising concerns about silent transmission of SARS-CoV-2 in healthcare settings.
A systematic review of 97 studies presented online at the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Conference on Coronavirus Diseases and published in the American Journal of Epidemiology found that 10% of HCW were positive via polymerase chain reaction testing and 7% by antibody tests. Nurses accounted for the most infections (48% of those infected), followed by physicians (25%) and other healthcare workers (23%). Five percent of healthcare workers with COVID-19 went on to develop severe clinical complications, and 0.5% subsequently died.
An analysis of the 15 studies that screened HCW irrespective of symptoms and reported the percent testing positive found that 40% did not report any COVID-19–compatible symptom during screening.
The authors write, “HCW suffer a significant burden from COVID-19, with HCW working in hospitalization/non-emergency wards and nurses being the most infected personnel.” The high prevalence of SARS-CoV-2 infection among nurses may reflect greater time spent with direct patient care, the authors say, while the higher rates of infection in hospitalization/non-emergency settings could demonstrate differences in personal protective equipment use.
To improve early detection and prevent transmission, the authors advocate for inclusion of additional symptoms in screenings of healthcare workers. In SARS-CoV-2–positive healthcare workers who were symptomatic at the time of screening, the most common symptoms were fever, anosmia (loss of smell), and myalgia (muscle aches). The authors conclude that screening only for fever, cough, shortness of breath, and sore throat “might have missed 17% of symptomatic HCW at the time of illness onset.”
The researchers conclude, “Universal screening for all exposed HCW regardless of symptoms should be the standard strategy to reduce transmission of SARS-CoV-2 in a hospital setting.” In an ESCMID news release, coauthor Oscar H. Franco, MD, PhD, of the University of Bern, Switzerland, adds, “It is clear that providing healthcare workers with adequate personal protective equipment and training is essential.”
Sep 22 ESCMID news release
Sep 1 Am J Epidemiol study
Death in COVID cancer patients tied to age, pre-existing conditions
A study of 435 German hospital patients presented online at the ESCMID Conference on Coronavirus Diseases found that cancer patients showed significantly worse outcomes and higher mortality rates than others with COVID-19, and these appear to be the result of age and pre-existing conditions rather than the cancer itself.
Researchers at Jena University Hospital in Germany studied a subset of 435 cancer patients from a sample of 3,071 COVID-19 patients enrolled in the multicenter Lean European Open Survey on SARS-CoV-2-Infected Patients (LEOSS) registry. The LEOSS registry, established by the German Society of Infectious Diseases (DGI), is an open-access database of clinical COVID-19 information.
Patients in the hospital study were assessed by sociodemographic status, comorbidities, functional status, and COVID-19 outcome. Common comorbidities included cerebrovascular disease (stroke), cardiovascular disease, and chronic kidney disease.
The researchers categorized COVID-19 into four phases: uncomplicated (asymptomatic or mild symptoms), complicated (need for supplemental oxygen), critical (need for life-supporting therapy) and recovery (improvement and discharge). Most of the cancer patients (63%) were in the uncomplicated phase of COVID-19 at the time of diagnosis. Fifty-five percent of patients progressed to the complicated or critical phase during the course of the study, and 119 patients (28%) required admission to an intensive care unit, with 78 requiring mechanical ventilation. The COVID-19 mortality rate for cancer patients was 23%, with men twice as likely to die as women—28% vs 14%.
The authors found that patients with active cancer disease, those with metastatic cancers, or those who had recently received anti-cancer therapy had higher mortality than those without active cancers (27% vs 17%). But patients in the study tended to be older and have greater comorbidities than non-cancer patients, so those factors, rather than cancer, played the larger role in rates of serious disease and death.
Lead author Maria Rüthrich, MD, said in an ESCMID news release, “After adjusting for age, sex and comorbidity, our results show that cancer patients are at higher risk of more serious disease and death due to being generally older than non-cancer patients with COVID-19, and also having more underlying conditions. It does not appear to be the cancer itself that is leading to these poor outcomes.”
Sep 23 ESCMID abstract
Sep 22 ESCMID news release
Routine blood test predicts COVID-19 mortality risk, study finds
A study today in JAMA shows that a routine blood test predicts increased risk of COVID-19 death in hospitalized patients. The study points to elevated red blood cell (RBC) distribution width (RDW), a measure of RBC volume variation and a standard part of a routine complete blood count test, as a tool to identify patients at higher risk of COVID-19 complications.
Senior author John M. Higgins, MD, of Massachusetts General Hospital (MGH), said in an MGH news release, “We wanted to help find ways to identify high-risk COVID patients as early and as easily as possible—who is likely to become severely ill and may benefit from aggressive interventions, and which hospitalized patients are likely to get worse most quickly.”
The study tracked RDW for 1,641 adults admitted to one of four Boston-area hospitals from Mar 4 to Apr 28. Patients with high RDW at the time of hospital admission (RDW > 14.5%), or whose RDW increased during their hospital stay, had a higher mortality rate than patients with normal RDW.
Patients who had RDW values above the normal range on hospital admission had a 2.7-times higher risk of dying, with a mortality rate of 31%, compared with 11% in patients who had normal RDW values. The association of RDW and increased mortality risk was observed across all age-groups and independent of demographic factors and comorbidities.
Although the mechanism behind COVID-19–elevated RDW is yet unclear, the authors suggest that it “may reflect a clinical state in which RBC production and turnover have slowed in the setting of increased production and turnover of leukocytes or platelets such as would occur in inflammation.”
While the study shows value for RDW as a diagnostic indicator for higher risk of complications, conclusions are limited by the small number of younger adults included in the study, its restriction to hospitalized patients, and the failure to capture socioeconomic data, the authors write. They say more research is needed to better determine its utility, but they conclude, “RDW may be helpful for patient risk stratification.”
Sep 23 JAMA study
Sep 23 MGH news release