Convalescent plasma has been widely and successfully used as a COVID-19 treatment. For example, a survey Sermo W3, April 15, shows that 46% of the doctors that had used convalescent plasma or had seen it used, said it is very or extremely effective against COVID-19.
Plasma has been positively mentioned in Hydroxychloroquine-based COVID-19 Treatment, A Systematic Review of Clinical Evidence and Expert Opinion from Physicians’ Surveys.
Nevertheless, it is a last resort tool, when everything else has failed. In order to receive this treatment, a patient must be hospitalized and the hospital must have a plasma supply. The dangers to the patient in this situation are real and not insignificant.
Hydroxychloroquine on the other hand, can and should be prescribed early, upon the first presentations of symptoms to prevent the aggravation of the disease and the need for hospitalizations.
Convalescent plasma is not a substitute for Hydroxychloroquine.