Plasma transfusion in COVID-19
(Dr Raheel Iftikhar, FCPS Medicine, FCPS Clinical hematology, FACP)
For information of general colleagues and health care providers.
There is undue hype created for use of convalescent plasma in COVID-19. Few facts which we need to keep in mind
1. Use of convalescent plasma in severe and critical SARS-CoV2 disease is against basic principles of immunology. Passive immunization works early in disease and for post exposure prophylaxis. It is not helpful in full blown disease. For example if you give immunoglobulin to patients with full blown rabies , tetanus, polio it will not work.
2. Median time for clearance of viremia is 11-14 days in studies , so if disease is this much old , no significant viral load will be available to be neutralized by convalescent plasma.
3. Cause of death in most of COVID patients is CRS and HLH , virus sets proinflammatory pathways and itself clears away , so in these patients Convalescent plasma won't work.
4. Currently there is no scientific evidence supported by randomized trial to suggest survival benefit of convalescent plasma in moderate to severe COVID-19.
5. COVID-19 antibody titre is not done except 1-2 places in Pakistan and only IgG testing is done , which is insufficient to check whether sufficient antibodies are generated in donor. Moreover NAT screening ( essential to prevent viral transmission like HEPATITIS, HIV) is not done by majority of centres . We are likely to see a large number of patients recieving plasma developing transfusion transmitted infections
6. Another thing is prothrombotic nature of COVID, giving plasma will be adding insult to injury
7. Use of Convalescent plasma is only allowed by FDA , and Govt of Pakistan as an investigational therapy as part of clinical trial, legally it cannot be administered without enrolling patient into that trial.
Considering above facts , there is no rationale of use of plasma therapy as it is currently being offered in Pakistan. It can be potentially more harm ful to patient than beneficial.