Reducing nosocomial transmission of COVID-19: implementation of a COVID-19 triage system

Abstract

Nosocomial transmission of COVID-19 puts patients with other medical problems at risk of severe illness and death. Of 662 inpatients with COVID-19 at an NHS Trust in South London, 45 (6.8%) were likely to have acquired COVID-19 in hospital. These patients had no evidence of respiratory or influenza-like illness on admission and developed symptoms, with positive SARS-CoV-2 PCR test results, more than 7 days after admission (>14 days for 38 [5.7%] patients). Forty (88.9%) of these patients had shared a ward with a confirmed COVID-19 case prior to testing positive. Implementation of a triage system combining clinical assessment with rapid SARS-CoV-2 testing facilitated cohorting so that fewer susceptible patients were exposed to COVID-19 on shared wards. With hospital service resumption alongside the possibility of future waves of COVID-19 related admissions, strategies to prevent nosocomial transmission are essential. Point-of-care diagnostics can complement clinical assessment to rapidly identify patients with COVID-19 and reduce risk of transmission within hospitals.

Keywords: COVID-19; infection control; nosocomial infection; patient isolation; point-of-care testing.

Fig 1.

Case categorisation. Flow chart to show categorisation of cases as hospital-associated COVID-19 if the patient had a positive test following >7 days in hospital, and likely or highly likely hospital-acquired COVID-19 if they had a positive test and symptom onset following >7 days in hospital.

Fig 2.

Proportion of cases categorised as hospital-associated and hospital-acquired and patterns of ward and bay sharing prior to infection. a) Bar chart to show the total number of patients admitted to hospital with COVID-19 by week, the proportion of cases that were categorised as ‘hospital-associated’ COVID-19 using NHS surveillance criteria of time from admission to positive test (>7 days), and the proportion that were categorised as ‘hospital-acquired’ COVID-19 using time from admission to symptom onset (>7 days). b) Diagram to show the number of patients with hospital-acquired COVID-19 who during the 14 days prior to testing positive were located in wards (box) or bays (circle) with confirmed COVID-19 patients who were likely to be infectious (during the 14 days after they tested positive). 40 (88.9%) patients were located on wards with COVID-19 cases during the 14 days prior to testing positive; 13 (28.9%) were located in the same bays.

Fig 3.

COVID-19 Likelihood Scoring Tool and flow-chart to guide testing and cohorting of patients admitted to hospital.