VIRAL RESPIRATORY-INFECTIONS IN THE COMMUNITY - EPIDEMIOLOGY, AGENTS,AND INTERVENTIONS

Viral respiratory infections are a leading cause of acute morbidity in the community. The annual frequency of respiratory illness rises duri ng the second year of Life, falls during subsequent years, increases a gain during child-bearing years, then decreases with advancing age (al though some increase may be seen in the elderly). In terms of restrict ion on activity and prompting of visits to physicians, the greatest nu mber of illnesses are associated with rhinoviruses followed by influen za viruses. However, comparing rhinovirus and influenza, there is no d oubt that influenza viruses produce more severe symptoms. In some year s, when there is a major influenza outbreak, they may even be identifi ed at greater frequency. Moreover, unlike with other viruses, severity of influenza infection is high at all ages, but especially in older i ndividuals. Influenza vaccine, which has been available for half a cen tury, has proved effective in preventing hospitalizations for pneumoni a and influenza during outbreaks of influenza types A and B. The antiv iral agents amantadine and rimantadine provide approximately equivalen t, and significant, efficacy in protection against clinical illness re sulting from influenza type A only. However, the potential for side ef fects is more marked with amantadine. Some studies have shown that the rate of treatment withdrawal is no greater with rimantadine than with placebo. As we enter the next century, we may well see improvements i n influenza vaccines, as well as the advent of antiviral agents that a re effective against both type A and type B influenza.