It won't be easy. Members of five viral families, including coronaviruses, influenza and parainfluenza viruses, and 100 rhinoviruses, cause colds. Coronavirus colds incubate a little longer and have a shorter duration than those due to rhinoviruses, but symptoms of both types are similar. Many drugs are antirhinoviral in vitro but so far few have worked clinically, says Baylor microbiologist Robert Couch. Though antibodies to rhinoviruses develop in seven to 14 days and last for years, the multiplicity of serotypes and lack of crossreacting antigens are problems in all immunization approaches.
Colds affect nearly everyone, but some cold virus infections have a subclinical course.
At Toronto's Hospital for Sick Children, a survey found more than 800 OTC cold preparations. Purdue virologist Michael G. Rossmann says rhinoviruses have vulnerabilities. Though small, each consists of 60 asymmetric units containing four viral polypeptides. Three of the peptides form a shell and have puffs that are binding sites of neutralizing antibodies. Rhinoviruses contain canyons that x-ray crystallography and electron microscopy indicate are the sites recognized by the cellular receptor molecules.