COVID-19 Convalescent Plasma Donor Characteristics: Correlation with Blood Group, Age, Gender, Symptoms and their Association with SARS CoV-2 Antibody Levels: A Bi-centric Study from India

Background: Understanding demographics and collection characteristics of Convalescent Plasma (CP) donors is the corner stone for maintaining a viable inventory of high titre CP products in an acute-crisis setting. The Specific objectives of this study were to find a correlation between SARS-CoV-2 antibody level with age, gender and blood group in CP donors.

Materials and Methods: An observational, retrospective study was conducted at blood centres of two multispecialty hospitals in Delhi from 1st November 2020 to 31st January 2021. 936 consenting COVID-19 recovered individuals were screened and underwent a medical interview for eligibility for CP donation from both blood centres, of which 750 qualified for CP collection. 400/ 750 (53.3%) CP donations were from centre A and 350/750 (46.7%) were from centre B. Donor characteristics data for both centres was retrieved from the blood bank donor management database and records from both the centres.

Results: The results of this study revealed that majority were males 727 (96.93%) and 23 (3.07%) were females with mean age was 35.09±8.7 years. 41-50 years showed higher median SARS-CoV-2 antibodies. Of the 936 donors screened for CP collection, 186 donors got deferred due to various reasons, resulting in a mean deferral rate of 19.87%. The commonest reason (15.05%) was absence of detectable/low SARS CoV-2 antibodies. Group-wise median antibody levels were AB>B>A>O at both centres. Moderate correlation (correlation coefficient =0.721) between number of symptoms and SARS CoV-2 antibody levels was observed; high symptom scores showed high SARS CoV-2 antibodies values (correlation coefficient=0.721; p < 0.00001). The individual symptom-wise predictors like fever (p= 0.002) and acute gastroenteritis (GE) or (GE-like syndrome) (p < 0.001) were positive predictors for high SARS CoV-2 antibodies. Cold (p = 0.006) and absence of symptoms (p = 0.060) were negative predictors. To summarize a collective significant effect exists between the symptoms and SARS CoV-2 antibody levels. Donors with symptoms like fever and GE or GE like syndrome showed significantly higher SARS Cov-2 antibodies. Female donors as compared to male donor, donors in age group of 41-50 years and donors with blood group AB compared with other groups had higher median levels of SARS CoV-2 antibodies.

Conclusion: Awareness of CP donor characteristics, post-screening deferrals, and correlates of antibody values with age, symptoms and blood group will help improve collection outcomes and give better preparedness for future recurrent waves due to evolution of more virulent SARS-CoV-2 strains and fill treatment gap till availability of more specific treatment.