By treating the population for pellagra:
* new COVID cases can be prevented (prophylactic)
* the severity and duration of COVID symptoms can be reduced (treatment)
* COVID-long can be cured (cure)

THE PROTOCOL: Niacin B3, Vitamin D, Vitamin C, Quercetin, Zinc, and Selenium.

The dosage depend on your Niacin B3 deficiency. COVID causes a Niacin deficiency. In addition, many people are deficient prior to contracting COVID. These cases often end in death (aged, hypertension, obese, and type2 diabetics.)

The following doses have cured severe deficiencies in COVID-long cases:
* Vitamin C, Quercetin and Selenium you can get from your diet. Careful not too much Selenium. One (1) Brazil nut a day is adequate Selenium.
* The Vitamin D is best gotten from 15 minutes a day in the sun. You can take 1000iu/day supplement, too.
* A 15mg Zinc/day supplement. Care should be taken not to overdose on Zinc. There are many zinc products which deliver different amounts of free zinc per milligram.
* The Niacin is the trickiest and most important part. You need to make sure you get the right kind of B3. Non-flush is no good. You can start with 35mg/day, but it will depend on your deficiency. The cured long hauler takes 50-75mg with each meal. (For a 6 month duration.)

Niacin is the most important ingredient in the protocol. Niacin is used to replenish NAD+. The other ingredients can not be processed without NAD+. Taking mega doses of Vitamin C or Vitamin D are of little to no help without NAD+.