Use of Carrageenan spray in the prevention of rhinovirus cold infection

INTERVENTION: A nasal spray containing saline solution and 1.6 mg/ml carrageenan will be taken by participants in the active group during cold season. Each participant will take one spray into each nostril 3 times each day for 8 weeks. The participants will take a daily record of cold symptoms and a nasal swab will be taken at the beginning and end of the study, as well as when cold symptoms develop, to ascertain levels of rhinovirus in the nose. CONDITION: Prevention of rhinovirus cold infection PRIMARY OUTCOME: Reduction in cold symptoms in recorded cold symptom diaries in the active group over an 8 week time period SECONDARY OUTCOME: Lower levels of rhinovirus positive nasal swabs in the active group compared to the placebo group INCLUSION CRITERIA: At least one cold infection reported in the previous year