Overview of Human Rhinovirus Infection and Exacerbations of Asthma

Asthma is an inflammatory disease of the airway, characterised by wheeze, dyspnoea, variable airflow and changes in lung function, airway hyperreactivity, and reversible bronchoconstriction. Recent evidence suggests a large proportion of asthma exacerbations are precipitated due to viral infections [1-5] and the most prominent respiratory virus is human rhinovirus (RV) [2, 6]. Adequate treatment of asthma exacerbations remains an important therapeutic goal. Inhaled corticosteroids (GCs) and long acting β2 agonists are common treatments for persistent asthma and asthma exacerbations, often used in combination. However, these treatments are only partially effective, reducing rates of asthma exacerbations by about 40% [7, 8]. There is an urgent need therefore to find improved therapeutic targets for asthma exacerbations.
Evidence from epidemiological studies show that numerous respiratory viruses are associated with acute exacerbations of asthma, accounting for up to 80–85% of acute exacerbations [1-3, 6, 9]. While RV is most prominent, other respiratory viruses such as respiratory syncytial virus (RSV), influenza viruses, parainfluenza viruses, coronaviruses, adenoviruses and the newly described metapneumoviruses, may also be associated with exacerbations of asthma. In children >2 years of age, RSV infection is a common cause of significant morbidity in the form of wheeze or bronchiolitis. In older children and adults, RSV is still implicated in exacerbations of acute asthma, but does not appear to be as important as RV [6, 9]. […]