Improving the Diagnosis and Management of COVID-19 and Respiratory Infections

Rapid diagnostics in hospitals and decentralised locations can improve patient management and promote antimicrobial stewardship, reducing inappropriate prescribing of medications.

Tony Cambridge, Thornhill Healthcare Events and Consultancy, Lead Biomedical Scientist (NHS)

The management of patients presenting with symptoms of respiratory infection in healthcare settings is a problem most clinicians and infection control teams are all too familiar with. Whether the setting is in the community or at hospital entry points, the uncertainty around the cause of the symptoms is crippling the efficient delivery of services and increases the risk to staff and patients being cared for in the same care delivery site.

In recent times there has been a paradigm shift in the approach to managing suspected infections, not least in infection control and prevention, but more profoundly by the emergence of SARS-CoV-2. Whereas the pressure on services from seasonal flu infections could be anticipated and planned for, the same cannot be said for this novel coronavirus. Instead there will now need to be year round initiatives, focussing on the identification, isolation and treatment of patients exhibiting the symptoms of SARS-CoV-2 infection along with the screening of all patients attending busy emergency departments or directly admitted to hospital. Other common respiratory infections must not be forgotten and a policy of comprehensive testing for those pathogens should also be considered.

Respiratory infections present with similar symptoms

Attendances at emergency departments, health centres, minor injury units and urgent care centres are returning to pre-COVID-19 levels, with patients seeking assessment of symptoms indicating an underlying health condition. With a wide range of common symptoms, dealing with suspected SARS-CoV-2 infections along with other respiratory infections has the potential to severely interrupt flow in any healthcare setting challenged with managing these patients.

Without appropriate infection prevention measures the potential for hospital acquired infections increases. The hospital population will comprise those patients more susceptible to respiratory infections and the debilitating effects they can have on patients with underlying health conditions and compromised immune systems. The need for rapid identification of pathogens causing infection has never been greater, and the panel of tests required never been wider.

Rapid diagnostics are emerging as an essential tool in identifying and containing infections whilst triaging patients with COVID-19 and other respiratory disease. Overcrowded emergency departments, poor hospital flow, increased length of stay and slow discharge times are all contributing to a suboptimal care system where demand outweighs capacity. Consideration should be given to the provision of diagnostics in decentralised locations such as community hubs, pharmacies, wellbeing centres, retail centres and mobile drop in units.

The emergence of rapid diagnostics

The perfect diagnostic test does not exist. Detection of viruses, and the differentiation of viral and bacterial infections, is central to the battle. Medical laboratory tests employing gold standard methodology still suffer from the impact of poor pre-analytical sampling technique, inappropriate timing of sampling, sample preparation and long analysis times. Sensitivity and specificity is high when samples have been obtained correctly, taken at the right time and processed by skilled staff. A wide range of point of care and rapid solutions are now available, showing very good performance when the aforementioned limitations are avoided. Analysis times are shortened in many cases, some to under 20 minutes, equipment can be situated in the departments under pressure, and some devices offer multiplexing – the ability to analyse multiple pathogens at the same time from one sample. A testing platform that can perform multiple tests from the same sample for SARS-CoV-2, influenza viruses (Flu A, Flu B) and Respiratory Syncytial Virus (RSV) will always be more attractive and ensures patients can be managed with more confidence.

This approach offers clinicians the opportunity to rule out specific infections with a high degree of certainty, allowing admission of the patient to general wards where normal infection prevention measures are in place. Those patients returning a positive rapid test result can be isolated in purpose built areas within emergency departments or assessment units, until a confirmatory result is obtained by the gold standard laboratory method, polymerase chain reaction (PCR). If the infection is confirmed then the patient can be admitted directly to an appropriate isolation ward where infection control measures are heightened. Hospitals must optimise bed management to avoid operational issues.

Early Adopter (EA) groups reported successful outcomes using point of care diagnostic tests, including ‘improved patient triage, better cohorting and use of isolation rooms during periods of winter pressures. Improved clinical outcomes may include more targeted use of antivirals, a reduction in unnecessary antibiotic use and a reduced length of hospital stay’¹.

Innovation is leading the way in tackling respiratory illnesses

In response to the worldwide need for easy to use diagnostic tests, manufacturers and distributors have developed and released a range of lateral flow devices, although significant differences in performance characteristics were identified in the early products coming to market. The sensitivity and specificity of these early devices indicated a high level of variation in performance, causing doubt around the utility and effectiveness of these tests in detecting active infections.

Whilst lateral flow antibody tests might give retrospective information on infection prevalence, especially in assessing regional variation, they are of no use in detecting the pathogen. Individual antibody levels can also vary making analysis of the obtained data difficult, and inaccurate conclusions may be drawn. Lateral flow antigen tests can detect infection but the genetic material detected by the test can be present in samples collected from infected patients long after the individual poses an infection risk. Positive results could lead to individuals isolating unnecessarily.

Evidence suggests that there is a difference between the viral load and infectivity between upper and lower respiratory tract infections for SARS-CoV-2 and that active virus becomes undetectable around two weeks after the onset of symptoms². This indicates that identifying infectious patients could be all the more difficult using any diagnostic test, in the laboratory or at the point of care.

Misdiagnosis of infections leads to poorer outcomes and inappropriate prescribing

Inappropriate diagnosis of respiratory infections leads to sub-optimal treatment decisions which can have a significant impact on patient outcomes, the health economy and operational pressures. Misdiagnosed infections increase the likelihood of inappropriate medications being prescribed. The over-use of antibiotics has led to antimicrobial resistance (AMR) and a strategy of antimicrobial stewardship (AMS) has been adopted in developed healthcare systems. But there remains a significant amount of work to do in terms of awareness and applying the guidance.

Tests are now available which improve the capability of differentiating between bacterial and viral infections and these solutions should be adopted in decentralised healthcare locations so that clinicians can avoid unnecessary and inappropriate prescriptions. Prescribing antimicrobials when the infection is viral serves no purpose, symptoms will persist and potentially become more pronounced, which in turn results in increased pressure on acute services. A rapid test, performed on site or at a nearby hub, would provide the information required for effective treatments.

It has been widely published that overuse of antibiotics is driving the prevalence of antimicrobial resistant infections³. Improper use of antimicrobials will only reduce when stringent protocols are adhered to and decisions are supported by rapidly available diagnostic data.

The Future of Molecular Point of Care Diagnostics

It is difficult to imagine the coronavirus pandemic being handled effectively without the use of rapid molecular diagnostic tools. Infection rates and associated death tolls across multiple territories may have been significantly higher had infectious individuals not been identified and isolated in order to protect hospitalised patients and the wider population. More needs to be done to ensure the adoption and future use of these essential tools is targeted, to optimise the benefits that have already been demonstrated across the healthcare landscape. As healthcare professionals become more accustomed to using point of care solutions it is paramount that pre-analytical processes are optimised along with the technology.

References

1. Point of Care Tests for Influenza and other Respiratory Viruses – Public Health England (2018)
2. SARS-CoV-2 detection, viral load and infectivity over the course of an infection – Kieran A. Walsh et al. J Infect 2020 Sept; 81(3): 357-371
3. Antibiotic overuse: a key driver of antimicrobial resistance – Laura J Shallcross and Dame Sally C Davies. British Journal of General Practice 2014; 64 (629): 604-605