Acute Respiratory Infections (ARIs) are a major contributor to antibiotic resistance, largely due to the over prescription of antibiotics driven by the subjective nature of clinical assessment. The ASPIRE II study aims to evaluate whether a Point-of-Care (POC) diagnostic test, utilising C-reactive protein (CRP) and Myxovirus resistance protein A (MxA) biomarkers to differentiate between viral and bacterial infections can support clinical decision-making and serve as an effective antimicrobial stewardship tool.

In the first ASPIRE study, in which the POC test was taken after the consultation, 20 participants produced results in the ratio 10:7:3 (negative, bacterial, viral) with a 75% agreement to the antibiotic prescription given by the physician following face-to-face consultation. The observational ASPIRE I Study identified the need for a rapid POC test and highlighted areas in which the test could have been used to prevent over-prescribing of antibiotics when ARI's are identified as viral. The FebriDx POC test was also useful in identifying instances where antibiotics were not prescribed, when a bacterial infection is presented, proving an effective decision-making tool for antibiotic stewardship.

Antibiotic stewardship is fast becoming an essential measure to improve antibiotic prescribing by clinicians. Antibiotic stewardship not only presents a cost-effective strategy for the NHS but addressed the issue of antimicrobial resistance (AMR) and protects patients from harm caused by unnecessary antibiotic use.

The economic costs of antibiotic resistance are largely unknown, but it is anticipated that with an increased number of cases, effects to the economy could be severe. Infections and infectious diseases cost England & Wales an estimated £30 billion a year, with many cases of acute respiratory infections (Chaplin, 2017). POC diagnostic tests in a clinical setting could give clinicians the ability to distinguish between microbial and viral infections, providing a more informed decision to antibiotic prescribing.

The purpose of this study is to build upon data generated by the ASPIRE study that determined by retrospective evaluation, that a POC immunoassay can accurately be used to guide clinician's prescription decision. The ASPIRE 2 study will use the POC assay as an interventional decision tool prior to the GP's consultation of a suspected acute respiratory infection (ARI).

Upon clinical assessment, the current clinical practice prescribes antibiotics based on symptoms reported by the patient and a subjective review by the GP. This results in antibiotics being prescribed from an informed decision made by the clinician, based only from patient symptoms. The use of a dual marker immunoassay could guide informed decisions based on qualitative data and degree of infection using POC testing in Primary Care.

The POC assay uses a dual marker immunoassay to differentiate between a viral and bacterial infection. C-reactive protein (CRP) is raised in the blood stream in response to inflammation. CRP can be elevated in viral infections, but generally the rise is to higher levels in bacterial infections, especially severe bacterial infections. Another blood protein, the MxA protein, is selectively increased in people with viral infections and therefore has the potential to greatly enhance the rapid distinction between viral and bacterial respiratory infections.

NICE guidance from 2014 recommends the use of CRP POC test in the diagnosis and appropriate management of lower respiratory tract infections in adults aged 18 and over (excluding people with COPD) after clinical assessment whether antibiotics should be prescribed. The study POC assay data could be used as an effective tool alongside NICE guidelines to prescribe antibiotics based on CRP concentration where an infection may be viral. Recent clinical studies suggest the POC test is highly effective, yielding over 80% sensitivity and over 90% specificity when identifying bacterial and viral infections in adults (NICE, 2020).

Inclusion Criteria:

• Subject >18 years of age.
• having new onset symptoms suggestive of acute respiratory infection (ARI within 7 days of seeking care: runny nose, nasal congestion, sore throat, cough, hoarse voice, shortness of breath) with or without fever.

Exclusion Criteria:

• Unable to provide informed consent.
• Undergoing end of life care.
• Immunocompromised or taking chemotherapy, oral steroids, or interferon.
• Receiving a live vaccine in the last 14 days.
• Taking antibiotics or antivirals in the last 14 days.
• Patients that have symptoms lasting more than 7 days.