Hidden in plain sight: the impact of human rhinovirus infection in adults

Abstract

Background: Human rhinovirus (HRV), a non-enveloped RNA virus, was first identified more than 70 years ago. It is highly infectious and easily transmitted through aerosols and direct contact. The advent of multiplex PCR has enhanced the detection of a diverse range of respiratory viruses, and HRV consistently ranks among the most prevalent respiratory pathogens globally. Circulation occurs throughout the year, with peak incidence in autumn and spring in temperate climates. Remarkably, during the SARS-CoV-2 pandemic, HRV transmission persisted, demonstrating its resistance to stringent public health measures aimed at curbing viral transmission.

Main body: HRV is characterised by its extensive genetic diversity, comprising three species and more than 170 genotypes. This diversity and substantial number of concurrently circulating strains allows HRVs to frequently escape the adaptive immune system and poses formidable challenges for the development of effective vaccines and antiviral therapies. There is currently a lack of specific treatments. Historically, HRV has been associated with self-limiting upper respiratory infection. However, there is now extensive evidence highlighting its significant role in severe lower respiratory disease in adults, including exacerbations of chronic airway diseases, such as asthma and chronic obstructive pulmonary disease (COPD), as well as pneumonia. These severe manifestations can occur even in immunocompetent individuals, broadening the clinical impact of this ubiquitous virus. Consequently, the burden of rhinovirus infections extends across various healthcare settings, from primary care to general hospital wards and intensive care units. The impact of HRV in adults, in terms of morbidity and healthcare utilisation, rivals that of the other major respiratory viruses, including influenza and respiratory syncytial virus. Recognition of this substantial burden underscores the critical need for novel treatment strategies and effective management protocols to mitigate the impact of HRV infections on public health.

Conclusion: This review examines the epidemiology, clinical manifestations, and risk factors associated with severe HRV infection in adults. By drawing on contemporary literature, we aim to provide a comprehensive overview of the virus's significant health implications. Understanding the scope of this impact is essential for developing new, targeted interventions and improving patient outcomes in the face of this persistent and adaptable pathogen.

Keywords: Adults; Asthma; COPD; Hospitalised patients; Pneumonia; Primary care; Respiratory virus; Rhinovirus.

Fig. 1

Overview of the structure, taxonomy, diversity, and infection targets of human rhinovirus (HRV). HRV is among the most diverse viral pathogens. The vast genetic diversity of circulating HRV strains hampers adaptive immunity, which is limited to homologous strains. Host defence is therefore largely dependent on innate responses. The co-circulation of these diverse strains also presents a challenge to the development of antiviral and vaccine therapies. Abbreviations: bp base-pairs, CHDR-3 Cadherin Related Family Member 3, ICAM-1 Intracellular Adhesion Molecule 1, LDL-R Low Density Lipoprotein Receptor, RV Rhinovirus, RNA Ribonucleic Acid, VP Viral Protein

Fig. 2

Overview of human rhinovirus (HRV) transmission. HRV is highly infectious and can be effectively transmitted through contact and airborne methods. While contact transmission has been accepted for some time, it now appears that spread via aerosols is likely the dominant method of transmission. HRV can be effectively transmitted during its asymptomatic incubation period

Fig. 3

Impact of rhinovirus infection in adults. HRV is a major global pathogen and is detected throughout the year. Upper respiratory manifestations, including the common cold, are the most common manifestation and while self-limiting are associated with a considerable societal cost. It is now increasingly apparent that HRV is a driver of severe lower respiratory manifestations in adults, including exacerbations of airway disease and pneumonia, on a scale comparable to that of other respiratory viruses. The severity of infection is determined by the complex interaction of host factors such as age, multimorbidity and immune dysfunction alongside other factors such as viral characteristics and the presence of bacterial co-infection. There is an urgent need for novel treatment options, as options currently available are merely supportive in nature