The Role of Biomarkers in Influenza and COVID-19 Community-Acquired Pneumonia in Adults

Abstract

Pneumonia is a growing problem worldwide and remains an important cause of morbidity, hospitalizations, intensive care unit admission and mortality. Viruses are the causative agents in almost a fourth of cases of community-acquired pneumonia (CAP) in adults, with an important representation of influenza virus and SARS-CoV-2 pneumonia. Moreover, mixed viral and bacterial pneumonia is common and a risk factor for severity of disease. It is critical for clinicians the early identification of the pathogen causing infection to avoid inappropriate antibiotics, as well as to predict clinical outcomes. It has been extensively reported that biomarkers could be useful for these purposes. This review describe current evidence and provide recommendations about the use of biomarkers in influenza and SARS-CoV-2 pneumonia, focusing mainly on procalcitonin (PCT) and C-reactive protein (CRP). Evidence was based on a qualitative analysis of the available scientific literature (meta-analyses, randomized controlled trials, observational studies and clinical guidelines). Both PCT and CRP levels provide valuable information about the prognosis of influenza and SARS-CoV-2 pneumonia. Additionally, PCT levels, considered along with other clinical, radiological and laboratory data, are useful for early diagnosis of mixed viral and bacterial CAP, allowing the proper management of the disease and adequate antibiotics prescription. The authors propose a practical PCT algorithm for clinical decision-making to guide antibiotic initiation in cases of influenza and SARS-CoV-2 pneumonia. Further well-design studies are needed to validate PCT algorithm among these patients and to confirm whether other biomarkers are indeed useful as diagnostic or prognostic tools in viral pneumonia.

Respiratory Viruses in Nosocomial Pneumonia: An Evolving Paradigm

“…is, though, not an issue. Multiple reports indicate that each of these viruses can cause severe illness in patients presenting to the hospital with CAP [ 27 , 28 ]. Moreover, in the articles reviewed above, the definitions of HAP and VAP necessitated that the patient meets standard clinical and radiographic criteria for new pneumonia.…”

"Multidrug-Resistant Bacteria Related to Covid-19 Infection: A Minireview"

“…ARDS in patients with COVID-19 can also increase the levels of this marker, as well as clinical conditions of biliary pancretitis, fungal infections, lung carcinoma, among others. However, although PCT is not a reliable marker of the presence of bacterial co-infection, its dosage of up to 0.25 ng/mL is indicative of its absence and is an aid to avoid inappropriate treatment with antibiotics in patients infected with SARS-CoV-2 [38,[41][42][43]. Among the advantages of using procalcitonin as an inflammatory marker, it can be also considered the absence of interference of its levels with the use of corticosteroids, rapid elevation after induction, high sensitivity, and simple dosing through a blood sample [38].…”

“…Its serum levels are directly associated with the severity of COVID-19 and worse clinical outcome. Patients with elevated CRP levels at the time of admission were associated with a higher risk of disease severity and of developing secondary pulmonary infections [31,38,41,43]. Several studies have demonstrated the correlation between CAP severity and PCT and CRP.…”

“…In the study by Schouten et al, secondary increases in CRP and PCT were associated with superinfections such as COVID-19 complications, but the use of tocilizumab is associated with a reduction in these markers. On the other hand, a study by Kooistra et al conducted with patients admitted to the Radboud University Medical Center in the Netherlands demonstrates data from 190 ICU patients who received treatment with immunomodulators such as dexamethasone and tocilizumab had their CRP levels suppressed even after a secondary infection, while these drugs did not affect PCT [41,43,45]. Presepsin serves as a bacterial lipopolysaccharide (LPS) receptor and is the soluble form of CD14, a glycoprotein expressed in monocytes and macrophages.…”

“…It has been demonstrated as a tool to indicate severity in sepsis diagnoses because it rises early, within the first two hours after infection, surpassing PCT and CRP. Carbonell's study points to presepsin as a non-specific biomarker for diagnosing pneumonia and its etiology, but several studies have described this marker as reliable for the severity of viral pneumonia and COVID-19 [41,45].…”