I eat a healthy diet and take magnesium, zinc, K2, D3 each day. I also take Hydroxychloroquine every other day (for IBS).
I developed a slight sore throat and started to sneeze. My nose started to become blocked. I inhaled 0.1% hydrogen peroxide solution using an ultrasonic nebuliser several times during the evening and night. The following morning the symptoms had almost disappeared and by afternoon I was fine.
I make the 0.1% solution by mixing 1 ml of 3% Hydrogen Peroxide (from any pharmacy) with 29 ml of deionised water. It has a faint smell when inhaled but doesn't sting or cause me to cough.
DISCLAIMER: I'm not a doctor; I'm not telling anyone to try this.
Careful or you risk "the squirts". Anything less than 3,000 mg should be ok.