Persistence of antibody response to SARS-CoV-2 in a cohort of haemodialysis patients with COVID-19.

BACKGROUND: Haemodialysis patients are extremely vulnerable to COVID-19. Their immune response after infection is unclear. We have found high seroconversion rates in this population with 95% developing antibodies. It is unclear if and how long these antibodies persist. Here we investigate this with serial antibody testing. METHODS: We identified haemodialysis patients who had confirmed SARS-CoV-2 between March-May 2020 and measured monthly antibodies (IgG/IgM) in those who survived. We used a semi-quantitative cut-off index (COI) to create a qualitative result and plotted optical density (OD) over time. We used linear regression to examine the slope, as well as noting peak OD and time to peak OD. We correlated these against baseline demographics, markers of illness severity, and comorbidities. RESULTS: 122 patients were analysed. All remained antibody positive during follow-up; for a minimum of 148 days. 71% had a positive gradient indicating increasing antibody positivity over time. We found that age (p = 0.01), duration of PCR positivity (p = 0.06) and presence of symptoms (p = 0.05) were associated with a longer time to peak OD. Immunosuppression did not alter peak OD but did lead to a non-significant increase in time to peak OD and more patients had a subsequent fall in Ab levels (p = 0.02). Diabetic patients were more likely to have a positive slope (OR 2.26). CONCLUSIONS: These results indicate that haemodialysis patients have a robust and sustained antibody response after confirmed COVID-19 infection with no suggestion that immunosuppression weakens this response. Although unclear what protection these antibodies confer, this encouraging that haemodialysis patients should respond to vaccination.

Can we improve the prescribing and delivery of oxygen on a respiratory ward in accordance with new British Thoracic Society oxygen guidelines?

The British Thoracic Society recommends oxygen delivery to achieve target oxygen saturation range between 94% and 98% for medically unwell adult patients, and 88% to 92% in patients at risk of hypercapnic respiratory failure. Interviews with our medical and nursing staff suggested that oxygen was sometimes being given to patients without a valid order and there was a failure to titrate oxygen to the stated oxygen saturation range. Our aim was to improve appropriate oxygen delivery to 90% of our patients on a 30-bedded respiratory ward within 3 months. We identified several key steps to safe oxygen delivery on our ward. These include the recording of target oxygen saturation range, the prescribing of an oxygen order on drug chart and the correct bedside delivery of oxygen to the patient. To help improve compliance of these key steps, the following plan-do-study-act (PDSA) interventions were undertaken: (1) Educational announcements at board rounds. (2) A communication oxygen poster. (3) Highlighting improvement progress to teams via email. (4) Pharmacist review of inpatient drug chart. (5) Display of target oxygen saturation range at patient bedside. At baseline, only 50% of drug charts had a recorded oxygen order and 60% of drug charts had a set target oxygen saturation range. Following PDSA interventions, both measures improved to 93%. Our main outcome measure of appropriate oxygen delivery to the patient improved from a baseline of 20% to 80% on completion. Our quality improvement programme has shown simple interventions can improve oxygen prescribing and appropriate delivery of oxygen to the patient. The most effective PDSA interventions were sharing our measurements via email and displaying target oxygen saturation ranges by the patient bedside. We aim to provide future oxygen educational sessions at induction to our staff and scale our quality improvement programme to other wards including our acute medical unit.