COVID-19 infection among patients with cancer in Australia from 2020 to 2022: a national multicentre cohort study

Background

The global COVID-19 pandemic disproportionately affected certain populations and its management differed between countries. This national study describes characteristics and outcomes of COVID-19 in patients with cancer in Australia.

Methods

We performed a multicentre cohort study of patients with cancer and COVID-19 from March 2020 to April 2022. Data were analysed to determine varying characteristics between cancer types and changes in outcomes over time. Multivariable analysis was performed to determine risk factors associated with oxygen requirement.

Findings

620 patients with cancer from 15 hospitals had confirmed COVID-19. There were 314/620 (50.6%) male patients, median age 63.5 years (IQR 50-72) and majority had solid organ tumours (392/620, 63.2%). The rate of COVID-19 vaccination (≥1 dose) was 73.4% (455/620). Time from symptom onset to diagnosis was median 1 day (IQR 0-3), patients with haematological malignancy had a longer duration of test positivity. Over the study period, there was a significant decline in COVID-19 severity. Risk factors associated with oxygen requirement included male sex (OR 2.34, 95% CI 1.30-4.20, p = 0.004), age (OR 1.03, 95% CI 1.01-1.06, p = 0.005); not receiving early outpatient therapy (OR 2.78, 95% CI 1.41-5.50, p = 0.003). Diagnosis during the omicron wave was associated with lower odds of oxygen requirement (OR 0.24, 95% CI 0.13-0.43, p < 0.0001).

Interpretation

Outcomes from COVID-19 in patients with cancer in Australia over the pandemic have improved, potentially related to changing viral strain and outpatient therapies.

Funding

This study was supported by research funding from MSD.

Rapid molecular determination of methicillin resistance in staphylococcal bacteraemia improves early targeted antibiotic prescribing: a randomized clinical trial

Empiric therapy of methicillin-susceptible Staphylococcus aureus (MSSA) infections with vancomycin is associated with poorer outcome than targeted therapy with β-lactams. Our objective was to evaluate whether rapid determination of methicillin resistance shortens the time from Gram stain to targeted antimicrobial therapy in staphylococcal bacteraemia, thereby reducing vancomycin overuse. This was a single-centre open parallel RCT. Gram-positive cocci in clusters in positive blood culture underwent real-time PCR for rapid species and methicillin resistance determination parallel to conventional microbiology. Patients were randomized 1:1 so that clinicians would be informed of PCR results (intervention group) or not (control group). Eighty-nine patients (intervention 48, control 41) were analysed. MRSA was identified in seven patients, MSSA in 46, and CoNS in 36. PCR results were highly concordant (87/89) with standard microbiology. Median time (hours) from Gram stain to transmission of methicillin-susceptibility was 3.9 (2.8-4.3) vs. 25.4 (24.4-26-7) in intervention vs. control groups (p <0.001). Median time (hours) from Gram stain to targeted treatment was similar for 'all staphylococci' [6 (3.8-10) vs. 8 (1-36) p 0.13] but shorter in the intervention group when considering S. aureus only [5 (3-7) vs. 25.5 (3.8-54) p <0.001]. When standard susceptibility testing was complete, 41/48 (85.4%) patients in the intervention group were already receiving targeted therapy compared with 23/41 (56.1%) in the control group (p 0.004). There was no significant effect on clinical outcomes. Rapid determination of methicillin resistance in staphylococcal bacteraemia is accurate and reduces significantly the time to targeted antibiotic therapy in the subgroup of S. aureus, thereby avoiding unnecessary exposure to vancomycin.

Safety and Efficacy Review of Doxycycline

Doxycycline is a member of the tetracycline class of antibiotics and has been used clinically for more than 40 years. It is a well-tolerated drug that is bacteriostatic and acts via the inhibition of bacterial ribosomes. It is generally given at a dose of 100-mg daily or twice daily. It is well absorbed and has generally good tissue penetration. The serum half-life is 18-22 hours and dosage does not need to be adjusted in the presence of renal or hepatic impairment. Major side effects are gastro-intestinal and dermatological and it is generally contra-indicated in pregnancy or childhood because of concerns about discolouration of developing teeth and potential effects on growing bones. Drug interactions are not common although can occur with the concomitant use of methotrexate and the oral contraceptive pill, and its absorption can be reduced by the co-administration with some antacids and iron preparations. It has activity against many organisms, including Gram-positives, Gram-negatives and atypical bacteria. In addition, it appears to have some potentially clinically useful anti-inflammatory properties.

Characterization of renal Na-K-ATPase gene expression by in situ hybridization

Na-K-ATPase is a heterodimer of alpha- and beta-subunits often referred to as the 'sodium pump' responsible for the maintenance of cell volume and electric potential across cell membranes. In the present study we have used antisense RNA probes to localize these subunits in the rat kidney by in situ hybridization. alpha 1-Subunit and beta-subunit gene expression are highest in cortical distal convoluted tubules, and the thick ascending limb of the loops of Henle; high in some proximal convoluted tubules, and low in the collecting ducts and blood vessels. Expression of the alpha 11 and alpha 111 isoforms is very low or absent throughout the kidney. These results confirm and extend studies of Na-K-ATPase enzyme activity levels and immunocytochemical localization in the kidney.