Routine Iodine Vs. Hypertonic Saline Nasal Sprays for H5N1 Prevention in Dairy and Cattle Frontline Workers

Preventive strategies necessary to reduce human and animal infection risk of serious bird flu.

By Nicolas Hulscher, MPH and Peter A. McCullough, MD, MPH

In addressing the H5N1 bird flu outbreak, public health measures should emphasize accessible preventive solutions, such as iodine-based nasal sprays and gargles, which hold promise in preventing zoonotic avian influenza transmission and human infection. Regular use of iodine nasal sprays by farmers, poultry workers, and veterinarians could help reduce viral carriage in the upper respiratory tract, lowering the risk of infection from direct animal exposure.

Sriwilaijaroen et al conducted a preclinical study of influenza virus strains on chicken egg cells and demonstrated that dilute povidone iodine (PVP-I) was effective at neutralizing the two pathogenic parts of the influenza virus—hemagglutinin (binding) and sialidase (catalytic hydrolysis). Of note, these effects were complimentary to the modest effect of oseltamivir (Tamiflu) in these experiments. As we outlined in a recent article, iodine-based antiseptics should also be explored for use in livestock and poultry settings, as indicated by Hnia et al, who found that a once-daily application of a PVP-I antiseptic with a film-forming agent effectively prevented influenza A virus transmission in a guinea pig model. Their study demonstrated that applying iodine to the nares of either the infected or susceptible animal—or both—significantly reduced transmission, even in a shared cage environment.

A clinical trial assessing the impact of a 0.5% PVP-I nasal spray on shedding of SARS-CoV-2 found:

Significantly improved reduction in viral load (log10 TCID50) on Days 2–4 com-pared to placebo recipients (p = 0.028), rate of nasal clearance of viable virus (p = 0.032), and complete (100%) nasal and throat clearance of the virus by Day 5.