Vitamin D is definitely something to make sure you've got enough of. Any disease can be a problem, even fatal, if our bodies and immune systems don't have adequate nutritional resources to take care of us. Dr. Zev Zelenko created a prophylactic protocol to prevent covid infections that included Vitamin D, Vitamin C, Zinc, and Quercetin, which enables the Zinc to prevent viruses from infecting us. Quercetin isn't as powerful as Ivermectin, but it's just as safe to use in proper dosage, and no one's trying to pretend it's for horses, or prevent people from getting it.