McMaster University professor investigating the use of convalescent plasma as a treatment to reduce the effects of COVID-19 in infected patients says a major study is suggesting it may not work.The study published in the journal Nature Medicine on Thursday suggests the deployment of blood plasma rich in antibodies from recovered COVID-19 patients “is extremely variable” and may actually create “more serious adverse events.”“It has been thought that the blood plasma of COVID-19 survivors would help those seriously ill from the virus but, unfortunately, it does not,” said Donald Arnold, co-principal investigator of the study, hematologist and professor of medicine at McMaster University.