Effect of inhalation of hot humidified air on experimental rhinovirus infection
J. O. Hendley, R. D. Abbott, P. P. Beasley and J. M. Gwaltney Jr
Department of Pediatrics, University of Virginia Health Sciences Center, Charlottesville 22908.
OBJECTIVE--Nasal inhalation of steam has been proposed as treatment of
viral colds on the assumption that increased intranasal temperature will
inhibit replication of rhinovirus (RV). The effect of steam inhalation on
RV shedding by infected volunteers was examined in this study.
DESIGN--Randomized controlled trial. Volunteers experimentally infected
with RV were treated with machine-generated humidified air, which was
either hot (active) or at room temperature (placebo). Viral shedding was
assessed over the 4 days following treatment. SETTING--Local hotel.
PARTICIPANTS--Twenty volunteers from the university community who were
susceptible to the challenge virus. INTERVENTION--Two 30-minute intranasal
treatments, the first at 24 hours after inoculation and the second at 48
hours. The temperature of active vapor was 42 degrees C to 44 degrees C and
of placebo vapor was 22 degrees C. MAIN OUTCOME MEASURES--Viral titers in
nasal washings on each of 5 days following inoculation. RESULTS--Mean viral
titers prior to the first treatment were 10(1.7) tissue culture infectious
doses per milliliter in the active group and 10(1.5) in the placebo group.
Mean titers for the next 4 days were 10(1.7), and 10(1.7), 10(1.2), and
10(0.9)/mL in the active group and 10(1.8), 10(1.9), 10(1.6), and
10(0.7)/mL in the placebo group (no significant difference). The proportion
of volunteers who shed virus on each day was also similar in the two
groups. CONCLUSION--Two nasal inhalation treatments with steam had no
effect on viral shedding in volunteers with experimental RV colds.
