Question 5. Answered by Samantha

5. Discuss progress towards vaccines to prevent the common cold.

Because conventional vaccine approaches do not appear feasible, current efforts are directed towards identifying effective antiviral compounds against rhinoviruses.

Following most rhinovirus infections, neutralizing antibodies develop in serum and nasal secretions. Unfortunately, those antibodies are only effective in preventing infection by the same rhinovirus serotype. Therefore, infection with a different serotype can readily occur. A vaccine to prevent rhinovirus infection does not appear feasible because it would have to comprise more than 100 serotypes. Nevertheless, several novel approaches to prophylaxis have been explored. One is the use of recombinant interferon-α administered by nasal spray. When given for 5 days before viral infection, interferon was 80% effective in preventing illness. However, when given longer than 5 days, interferon led to nasal symptoms as bothersome as those of a cold. Interferon treatment of rhinovirus infection is no longer being pursued because it is not effective in clearing an established infection. Antiviral drugs that inhibit various stages of the life cycle have been developed. They include compounds that bind the viral capsid and block uncoating of the viral RNA and inhibitors of the viral proteases. Although some of the compounds have proven safe and effective in clinical trials, their effectiveness is reduced by the emergence of resistant viral strains. Further compromising the effectiveness of antiviral drugs is the short duration of virus shedding and illness.