Just seeing this now. Thanks for the advice. I will give propolis, ginger, and vitamin c a try. Following up on what you have said, I guess the best prevention is good self-care: hydration, diet, sleep, regular exercise, and normal amounts of stress.
For anyone interested in learning more about propolis, here is an article from the National Library of Medicine: Propolis: A Wonder Bees Product and Its Pharmacological Potentials:
https://pmc.ncbi.nlm.nih.gov/articles/PMC3872021/#B22