The potential for a protective vaccine for rhinovirus infections.

Rhinovirus (RV) infections impose a major disease burden as they cause around three out of four common colds and are responsible for the majority of acute exacerbations of chronic obstructive pulmonary disease (COPD) and asthma. RVs therefore are associated with an enormous economic cost in missed work or school and medical attention. Prophylactic vaccination against infection is arguably the most effective medical intervention ever developed, and has proven enormously effective in protecting against a large number of diseases. However, at the present time no effective vaccine exists for RVs. This is largely due to the existence of 100 serotyped antigenically distinct RV strains - such variability means that a vaccine designed to elicit immune responses against a particular RV is unlikely to be able to provide protection against the full range of virus subtypes successfully. In fact, this phenomenon was observed as early as 1965 when immunising with formalin inactivated whole RV and is confirmed by the knowledge that the immunity induced following RV infection does not significantly protect from future infection by different RV serotypes. More sophisticated attempts at immunisation with multiple inactivated RV serotypes also failed to induce significant cross-serotype protection. Thus, an effective cross-serotype responsive RV vaccine has remained elusive. The relatively recent description of a new clade of RV types (RV-C) has increased the number of identified strains/serotypes to ~160. Perhaps the quest for a RV vaccine has been dismissed as too difficult or even impossible, but new developments suggest that it may be feasible to generate a significant breadth of immune protection.