OTC nasal spray seemed to cut COVID infections by 67% in mid-sized trial

A recent study published in JAMA Internal Medicine highlights the potential of an over-the-counter allergy nasal spray in reducing COVID-19 infections. Conducted by researchers at Saarland University in Germany, the mid-stage trial revealed a remarkable 67% reduction in infections among participants using the spray. The randomized, double-blind, placebo-controlled Phase 2 trial involved 450 healthy adults from March 2023 to July 2024. Participants were divided into two groups, with one group applying the antihistamine nasal spray azelastine three times daily, while the other group received a placebo spray that lacked the active ingredient. Both groups were comparable in terms of prior COVID-19 vaccinations and infection histories. After approximately 56 days of treatment, only five individuals (2.2%) in the nasal spray group contracted a SARS-CoV-2 infection, compared to 15 individuals (6.7%) in the placebo group. This significant difference translates to a 4.5 percentage-point reduction in infections, indicating the spray's potential effectiveness. Additionally, those who tested positive after using the allergy spray experienced a delayed onset of infection, averaging 31 days before testing positive, compared to 19.5 days for the placebo group. Moreover, participants using the nasal spray appeared to clear the virus more quickly, with a shorter duration of positive rapid antigen tests—3.4 days versus 5.1 days among those in the placebo group. Remarkably, the nasal spray group also reported fewer respiratory infections overall, with 21 infections compared to 49 in the placebo group. This trend was particularly evident in rhinovirus infections, commonly associated with the common cold. These findings align with previous research suggesting that azelastine may have the ability to combat various viruses targeting the nasal region. While the exact mechanism through which the spray operates on the nasal mucous membranes remains uncertain, the study indicates that it may offer broad protection against COVID-19 and other respiratory viruses.