Characteristics of convalescent plasma donors and their antibody titers in Bangladesh

Ponkaj K. Datta, M. Mujibur Rahman, Ahmedul Kabir, M. Mazharul Hoque, Motlabur Rahman, Mohammad Mahfuzul Hoque, Kashfia Islam, Khairul Islam, A. B. M. Al-Mamun, Pratyay Hasan


Background: Convalescent plasma is considered a promising therapy for severe COVID-19 disease. It is collected from the voluntary donors. Measurement of the antibody titer is necessary before transfusion to predict the outcome in the recipients. Characteristics of the convalescent plasma donors in Bangladesh and their antibody titers are not known.

Methods: Convalescent plasma was collected from the voluntary donors who survived the COVID-19 disease to transfuse to the severe COVID-19 patients under a randomized control trial. Total IgG antibody titer was measured in the donor plasma by indirect enzyme-linked immunosorbent assay. Data was collected in a preformed questionnaire before donor plasma collection.

Results: The median age is 32 (18-55) years.  Fever, cough, sore throat, diarrhea was most common among 68.3% of the symptomatic participants and the remaining 31.7% were asymptomatic at the time when they were RT-PCR positive. Overall, 57.1% of participants had mild symptoms, 11.1% had moderate symptoms and none had severe symptoms. Participants’ antibody titers were measured 41.68±14.072SD days after the RT-PCR positive date.  Rapid qualitative test could not detect antibody in 11 (17.5%) potential donors. Of the remaining 52 (82.5%) antibody positive participants titer was measured in 43 participants and found 1:320 in 17 (27.0%) (n=63), 1:160 in another 17 (27.0%) (n=63) and 1:80 in rest of the 9 (14.28%) (n=63) Participants. The mean titer of the donors who were hospitalized during their illness (1:274.29) was statistically significantly higher (p=0.043, CI>95%). The mean titer was also higher in female than in male, symptomatic than asymptomatic participants and in donors of A positive blood group. However, these finding are not statistically significant. Antibody titer does not correlate with time of RT-PCR negativity from initial RT-PCR positivity, time from RT-PCR positivity to titer date, age and body mass index.

Conclusions: All RT-PCR positive COVID-19 patients subsequently may not develop antibody. Although antibody titer among hospitalized symptomatic patients was significantly higher, further study is needed to recommend optimal convalescent plasma donor criteria. 


Antibody titer, Convalescent plasma, COVID-19, Plasma donation

Full Text:



Piechotta V, Chai KL, Valk SJ, Doree C, Monsef I, Wood EM et al. Convalescent plasma or hyperimmune immunoglobulin for people with COVID‐19: a living systematic review. Cochrane Database Syste Rev. 2020;7:CD013600

McGuire LW, Redden WR. Treatment of Influenza Pneumonia by the use of Convalescent Human Serum: Preliminary Report. J Am Med Asso. 1918;71(16):1311-2.

Casadevall A, Pirofski LA. The convalescent sera option for containing COVID-19. J Clin Investi. 2020;130(4):1545-8.

Bao L, Deng W, Gao H, Xiao C, Liu J, Xue J et al. Reinfection could not occur in SARS-CoV-2 infected rhesus macaques. bioRxiv. 2020.

Shen C, Wang Z, Zhao F, Yang Y, Li J, Yuan J et al. Treatment of 5 Critically Ill Patients With COVID-19 With Convalescent Plasma. JAMA. 2020;323(16):1582-9.

Wu F, Wang A, Liu M, Wang Q, Chen J, Xia S et al. Neutralizing antibody responses to SARS-CoV- 2 in a COVID-19 recovered patient cohort and their implications. medRxiv. 2020.

Wajnberg A, Mansour M, Leven E, Bouvier NM, Patel G, Firpo A, et al. Humoral immune response and prolonged PCR positivity in a cohort of 1343 SARS-CoV 2 patients in the New York City region. medRxiv. 2020.

To KK, Tsang OT, Leung WS, Tam AR, Wu TC, Lung DC et al. Temporal profiles of viral load in posterior oropharyngeal saliva samples and serum antibody responses during infection by SARS-CoV-2: an observational cohort study. Lancet Infect Dis. 2020;20(5):565-74.

US food and drug administration. Recommendations for Investigational COVID-19 Convalescent Plasma. Available at: Accessed 7 October 2020.

Zhang L, Pang R, Xue X, Bao J, Ye S, Dai Y et al. Anti-SARS-CoV-2 virus antibody levels in convalescent plasma of six donors who have recovered from COVID-19. Aging (Albany NY). 2020;12:6536-42.

Wu F, Liu M, Wang A, Lu L, Wang Q, Gu C et al. Evaluating the Association of Clinical Characteristics with Neutralizing Antibody Levels in Patients Who Have Recovered from Mild COVID-19 in Shanghai, China. JAMA Intern Med. 2020;180(10):1356-62.

Chen W, Zhang J, Qin X, Wang W, Xu M, Wanget L et al. SARS-CoV-2 neutralizing antibody levels are correlated with severity of COVID-19 pneumonia. Biomed Pharmacotherapy. 2020;130:110629.

Zhao J, Yuan Q, Wang H, Liu W, Liao X, Su Y et al. Antibody responses to SARS-CoV-2 in patients of novel coronavirus disease 2019. Clin Infect Dis. 2020;ciaa344.

Li L, Tong X, Chen H, He R, Lv Q, Yang R et al. Characteristics and serological patterns of COVID-19 convalescent plasma donors: optimal donors and timing of donation. Transfusion. 2020;60(8):1765-72.

Zhao J, Yuan Q, Wang H, Liu W, Liao X, Su Y et al. Antibody responses to SARS-CoV-2 in patients of novel coronavirus disease 2019. Medrxiv (pre-print). 2019;71(16):2027-34.

Zeng F, Dai C, Cai P, Wang J, Xu L, Li J et al. A comparison study of SARS‐CoV‐2 IgG antibody between male and female COVID‐19 patients: A possible reason underlying different outcome between sex. J Med Virol. 2020;92:2050-4.

Ko JH, Joo EJ, Park SJ, Baek JY, Kim WD, Jee J et al. Neutralizing Antibody Production in Asymptomatic and Mild COVID-19 Patients, in Comparison with Pneumonic COVID-19 Patients. J Clin Med. 2020;9(7):2268.

Kong W, Zhao R, Zhou J, Wang F, Kong D, Sun J et al. Serologic Response to SARS-CoV-2 in COVID-19 Patients with Different Severity. Virol. Sin. 2020;9:3372.

Tan W, Lu, Zhang J, Wang J, Dan Y, Tan Z et al. Viral Kinetics and Antibody Responses in Patients with COVID-19 (preprint). medRxiv. 2020.

Li L, Tong X, Chen H, He R, Lv Q, Yang R et al. Characteristics and serological patterns of COVID-19 convalescent plasma donors: optimal donors and timing of donation. Transfusion. 2020;60(8):1765-72.

Madariaga MLL, Guthmiller J, Schrantz S, Jansen MO, Christensen C, Kumar M et al. Clinical predictors of donor antibody titer and correlation with recipient antibody response in a COVID-19 convalescent plasma clinical trial. medRxiv. 2020.

Brown JF, Dye JM, Tozay S, Jeh-Mulbah G, Wohl DA, Fischer WA et al. Anti-Ebola Virus Antibody Levels in Convalescent Plasma and Viral Load After Plasma Infusion in Patients with Ebola Virus Disease. J Infect Dis. 2018; 218:555-62.

Chen J, Zhu H, Horby PW, Wang Q, Zhou J, Jiang H et al. Specificity, kinetics and longevity of antibody responses to avian influenza A(H7N9) virus infection in humans. J Infect. 2020;80:310-19.

Amanat F, Nguyen T, Chromikova V, Strohmeier S, Stadlbauer D, Javier A, et al. A serological assay to detect SARS-CoV-2 seroconversion in humans. medRxiv. 2020.