Preventing upper respiratory tract infections with prophylactic nasal carrageenan: a feasibility study

Aim: To observe upper respiratory tract infection (URTI) symptoms, rhinovirus levels and compliance with daily carrageenan nasal spray. Methods: 102 adults were randomized to carrageenan or saline placebo three times daily for 8 weeks and URTI symptoms were recorded. A control group (n = 42) only recorded URTI symptoms. Participants collected nasal swabs when symptomatic. Results: Regular daily carrageenan prophylaxis resulted in consistent but nonsignificant reductions in URTI symptoms versus the placebo group. Saline placebo decreased and increased some cold symptoms compared with no treatment. Conclusion: Daily prophylactic administration of antiviral carrageenan may not significantly reduce URTI symptoms. Due to low compliance, use in a population with specific reasons to avoid URTIs may be more appropriate. Disease-specific outcomes may be more useful than symptom reporting.