Ribavirin Aerosol Treatment of Influenza

Abstract

In this article we have described the clinical and laboratory features of uncomplicated influenza in college students and its treatment with ribavirin aerosol. The disease presents as an acute febrile systemic illness of short duration that varies little from patient to patient. Peripheral blood cell changes in the infection are also quite specific and very consistent. Polymorphonuclear cell counts are slightly increased above normal early in infection at a time when lymphocyte counts were greatly reduced. As lymphocyte numbers increase at the third day of illness, polymorphonuclear cell counts diminish substantially. Eosinophil counts fluctuate in a pattern similar to that of lymphocytes. Basophil, monocyte, and band cell counts are increased at admission and thereafter decline in numbers. Reticulocytes and platelets are reduced during acute illness. We assume that changes in peripheral white blood cell counts during influenza result from migration of cells to the inflamed respiratory tract and subsequent resupply of the various types of cells to the circulation from other sites in the body. The cellular alterations in the circulation and at the site of infection are of fundamental importance in the pathogenesis of infection, and a better knowledge of them should open new avenues for prevention and treatment. Aerosol treatment was shown to alleviate the symptoms of influenza and to reduce the shedding of influenza virus from the respiratory tract. No evidence of untoward effect of ribavirin treatment on peripheral white or red blood cells was found, and a wide range of clinical chemical tests revealed no toxic effects of treatment. There was no pulmonary irritation detected from the treatment. Reference was made to prompt recovery of four patients with influenzal pneumonia treated with ribavirin aerosol. Ribavirin aerosol must produce its major therapeutic effect through inhibition of virus replication at the sites of infection in the respiratory epithelium. This appears to result mainly from interference with viral messenger RNA initiation and elongation. This is best demonstrated by the prompt decline in viral shedding in treated patients. The associated prompt clinical improvement suggests that illness results from continued virus replication, and when virus replication is retarded, improvement follows. Although treatment promptly reduces illness and virus shedding, antibody response is not reduced in treated patients. We emphasized that ribavirin aerosol had a major therapeutic effect on infections caused by both influenza A and B viruses, and the picture of illness with these types of influenza was not clinically distinguishable.(ABSTRACT TRUNCATED AT 250 WORDS)