Prophylactic effect of low doses of human leukocyte interferon against infection with rhinovirus

The prophylactic effect of low doses of human leukocyte interferon (HuIFN-a) against infection with rhinovirus was measured in double-blind, placebo-controlled studies with volunteer subjects. An antihistamine (chlorpheniramine) was given before administration of single or multiple doses of HuIFN-a by saturated cotton pledget or by aerosol; volunteers were then challenged with rhinovirus. When the results for all groups were combined, a lower frequency of respiratory illness was demonstrated in the HuIFNa-treated volunteers (20 of 39 vs. 11 of 38, P < 0.05). A significant improvement in mean symptom scores was found only in the volunteers who received HuIFN-a by cotton pledget. The total numbers of isolates of rhinovirus and seroconversions were similar for HuIFN-a-treated and control volunteers. No significant side effects were noted in the HuIFN-a-treated volunteers. Higher concentrations or improved methods of delivery of HuIFN-a will be necessary for improving the clinical efficacy of HuIFN-a against viral infections in the respiratory system.