Adverse Effects of Aspirin, Acetaminophen, and Ibuprofen on Immune Function, Viral Shedding, and Clinical Status in Rhinovirus-Infected Volunteers

A double-blind, placebo-controlled trial was conducted to study the effects of over-the-counter analgesic/antipyretic medications on virus shedding, immune response, and clinical status in the common cold. Sixty healthy volunteers were challenged intranasally with rhinovirus type 2 and randomized to one of four treatment arms: aspirin, acetaminophen, ibuprofen, or placebo. Fifty-six volunteers were successfully infected and shed virus on at least 4 days after challenge. Virus shedding, antibody levels, clinical symptoms and signs, and blood leukocyte levels were carefully monitored. Use of aspirin and acetaminophen was associated with suppression of serum neutralizing antibody response (P < .05 vs. placebo) and increased nasal symptoms and signs (P< .05 vs. placebo). A concomitant rise in circulating monocytes suggested that the suppression of antibody response may be mediated through drug effects on monocytes and/or mononuclear phagocytes, There were no significant differences in viral shedding among the four groups, but a trend toward longer duration of virus shedding was observed in the aspirin and acetaminophen groups. In 1975, Stanley et al. [1] reported that aspirin significantly increased virus shedding in rhinovirus-infected volunteers compared with those taking placebo. Because volunteers were started on aspirin before any symptoms had developed, this study did not replicate usual clinical practice but nonetheless suggested that aspirin might suppress the normal immune response to upper respiratory tract infection (URI). Mogabgab and Pollock [2] reported a subsequent experiment that found no differences in virus shedding between aspirin-and placebotreated volunteers. In that study, volunteers were not given medication until symptoms started, more closely reflecting the situation in community-acquired infections. Unfortunately, pharyngeal washings were used to detect virus shedding instead of the significantly more sensitive method of obtaining nasal or nasopharyngeal washings [3], yielding a very low infection rate. Thus, the evidence is equivocal, and the question of aspirin effects on virus shedding remains open. In addition to aspirin, acetaminophen and ibuprofen are