A method for killing or substantially eradicating a pathogen in the upper respiratory tract of a mammal is disclosed. The method comprises generating molecular iodine (I2) in situ using an oxidant-reductant reaction with a minimum concentration of at least about 25 ppm of I2 and I2 comprises at least 40% of the total iodine atoms. A method for inhibiting superantigens using molecular iodine is also disclosed.