Nasal sprays and behavioural interventions compared with usual care for acute respiratory illness in primary care: a randomised, controlled, open-label, parallel-group trial

Background:
Limited evidence suggests that nasal sprays, or physical activity and stress-management, could limit respiratory infections. This study aimed to assess the impact on respiratory illnesses from nasal sprays or promoting physical activity and stress-management.

Methods.:
13799 participants aged >=18, from 332 GP practices, with co-morbidities and/or >=3 self-reported recurrent illnesses , were randomised by online software to: i) usual care (n=3451) ii) gel-based spray (n=3448) (2 sprays per nostril, up to 6 times/day) iii) saline spray (n=3450) (same dosing), or iv) a brief behavioural website promoting physical activity and stress-management (n=3450). The sprays were relabelled. Primary outcome: respiratory illness days over 6 months. Harms: side effects, antibiotic use.

Findings:
The usual care group (n=2983 analysed) had a mean of 8 self-reported illness days which was reduced in both spray groups (gel-based (n=2935) 6.5 days adjusted incidence rate ratio (IRR) 0.82, 99% CIs 0.76, 0.90, p<0.0001), Saline (n=2967) 6.4 days (IRR 0.81; 0.74,0.88, p<0.0001), behavioural website (n=2727) 7.4 days (0.97; 0.91, 1.04), p=0.46); for those reporting an illness it was 15,12,11.8 and 14 days respectively. Headache was more common with the gel-based spray (7.8%(199/2556) vs 4.8% (123/2547) usual care; risk ratio 1.61, 95% CIs 1.30 to 1.99, p<0.0001), but antibiotic use was lower for all interventions (IRRs (95% CIs) respectively 0.65 (0.50 to 0.84;p=0.001), 0.69 (0.45,0.88;p=0.003), 0.74 (0.57 to 0.94;p=0.02)).

Interpretation:
Advice to use either nasal spray at the first sign of an RTI reduced illness duration and both sprays and the behavioural website reduced antibiotic use.