Characteristics and serological patterns of COVID-19 convalescent plasma donors: optimal donors and timing of donation.

The lack of effective treatments against the 2019 coronavirus disease (COVID-19) has led to the exploratory use of convalescent plasma for treating COVID-19. Case reports and case series have shown encouraging results. This study investigated SARS-CoV-2 antibodies and epidemiological characteristics in convalescent plasma donors, to identify criteria for donor selection. Recovered COVID-19 patients, aged 18-55 years, who had experienced no symptoms for more than 2 weeks, were recruited. Donor characteristics such as disease presentations were collected and SARS-CoV-2 N-specific IgM, IgG, and S-RBD-specific IgG levels were measured by enzyme-linked immunosorbent assay (ELISA). Whereas levels of N-specific IgM antibody declined after recovery, S-RBD-specific and N-specific IgG antibodies increased after 4 weeks from the onset of symptoms, with no significant correlation to age, sex, or ABO blood type. Donors with the disease presentation of fever exceeding 38.5°C or lasting longer than 3 days exhibited higher levels of S-RBD-specific IgG antibodies at the time of donation. Of the 49 convalescent plasma donors, 90% had an S-RBD-specific IgG titer of ≥1:160 and 78% had a titer of ≥1:640 at the time of plasma donation. Of the 30 convalescent plasma donors, who had donated plasma later than 28 days after the onset of symptoms and had a disease presentation of fever lasting longer than 3 days or a body temperature exceeding 38.5°C, 100% had an S-RBD-specific IgG titer of ≥1:160 and 93% had a titer of ≥1:640. This study indicates that the S-RBD-specific IgG antibody reaches higher levels after 4 weeks from the onset of COVID-19 symptoms. We recommend the following selection criteria for optimal donation of COVID-19 convalescent plasma: 28 days after the onset of symptoms and with a disease presentation of fever lasting longer than 3 days or a body temperature exceeding 38.5°C. Selection based on these criteria can ensure a high likelihood of achieving sufficiently high S-RBD-specific IgG titers.

Li L ，Tong X ，Chen H ，He R ，Lv Q ，Yang R ，Zhao L ，Wang J ，Xu H ，Liu C ，Chen G ，Chen S ，Li C ，Qiao J ，Yang J ，Wu Y ，Liu Z ... -  《-》

Feasibility of a pilot program for COVID-19 convalescent plasma collection in Wuhan, China.

A novel coronavirus has caused an international outbreak. Currently, there are no specific therapeutic agents for coronavirus infections. Convalescent plasma (CP) therapy is a potentially effective treatment option. Patients who had recovered from COVID-19 and had been discharged from the hospital for more than 2 weeks were recruited. COVID-19 convalescent plasma (CCP)-specific donor screening and selection were performed based on the following criteria: 1) aged 18-55 years; 2) eligible for blood donation; 3) diagnosed with COVID-19; 4) had two consecutive negative COVID-19 nasopharyngeal swab tests based on PCR (at least 24 hr apart) prior to hospital discharge; 5) had been discharged from the hospital for more than 2 weeks; and 6) had no COVID-19 symptoms prior to convalescent plasma donation. In addition, preference was given to CCP donors who had a fever lasting more than 3 days or a body temperature exceeding 38.5°C (101.3°F), and who donated 4 weeks after the onset of symptoms. CCP collection was performed using routine plasma collection procedures via plasmapheresis. In addition to routine donor testing, the CCP donors' plasma was also tested for SARS-CoV-2 nucleic acid and S-RBD-specific IgG antibody. Of the 81 potential CCP donors, 64 (79%) plasma products were collected. There were 18 female donors and 46 male donors. There were 34 first-time blood donors and 30 repeat donors. The average time between CCP collection and initial symptom onset was 49.1 days, and the average time between CCP collection and hospital discharge was 38.7 days. The average volume of CCP collected was 327.7 mL. All Alanine transaminase (ALT) testing results met blood donation requirements. HIV Ag/Ab, anti-HCV, anti-syphilis, and HBsAg were all negative; NAT for HIV, HBV, and HCV were also negative. In addition, all of the CCP donors' plasma units were negative for SARS-CoV-2 RNA. Of the total 64 CCP donors tested, only one had an S-RBD-specific IgG titer of 1:160, all others had a titer of ≥1:320. Based on a feasibility study of a pilot CCP program in Wuhan, China, we demonstrated the success and feasibility of CCP collection. In addition, all of the CCP units collected had a titer of ≥1:160 for S-RBD-specific IgG antibody, which met the CCP quality control requirements based on the Chinese national guidelines for CCP.

Li L ，Yang R ，Wang J ，Lv Q ，Ren M ，Zhao L ，Chen H ，Xu H ，Xie S ，Xie J ，Lin H ，Li W ，Fang P ，Gong L ，Wang L ，Wu Y ，Liu Z ... -  《-》

Anti-SARS-CoV-2 virus antibody levels in convalescent plasma of six donors who have recovered from COVID-19.

Zhang L ，Pang R ，Xue X ，Bao J ，Ye S ，Dai Y ，Zheng Y ，Fu Q ，Hu Z ，Yi Y ... -  《Aging-US》

Decline of Humoral Responses against SARS-CoV-2 Spike in Convalescent Individuals.

In the absence of effective vaccines and with limited therapeutic options, convalescent plasma is being collected across the globe for potential transfusion to coronavirus disease 2019 (COVID-19) patients. The therapy has been deemed safe, and several clinical trials assessing its efficacy are ongoing. While it remains to be formally proven, the presence of neutralizing antibodies is thought to play a positive role in the efficacy of this treatment. Indeed, neutralizing titers of ≥1:160 have been recommended in some convalescent plasma trials for inclusion. Here, we performed repeated analyses at 1-month intervals on 31 convalescent individuals to evaluate how the humoral responses against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Spike glycoprotein, including neutralization, evolve over time. We observed that the levels of receptor-binding-domain (RBD)-specific IgG and IgA slightly decreased between 6 and 10 weeks after the onset of symptoms but that RBD-specific IgM levels decreased much more abruptly. Similarly, we observed a significant decrease in the capacity of convalescent plasma to neutralize pseudoparticles bearing wild-type SARS-CoV-2 S or its D614G variant. If neutralization activity proves to be an important factor in the clinical efficacy of convalescent plasma transfer, our results suggest that plasma from convalescent donors should be recovered rapidly after resolution of symptoms.IMPORTANCE While waiting for an efficient vaccine to protect against SARS-CoV-2 infection, alternative approaches to treat or prevent acute COVID-19 are urgently needed. Transfusion of convalescent plasma to treat COVID-19 patients is currently being explored; neutralizing activity in convalescent plasma is thought to play a central role in the efficacy of this treatment. Here, we observed that plasma neutralization activity decreased a few weeks after the onset of the symptoms. If neutralizing activity is required for the efficacy of convalescent plasma transfer, our results suggest that convalescent plasma should be recovered rapidly after the donor recovers from active infection.

Beaudoin-Bussières G ，Laumaea A ，Anand SP ，Prévost J ，Gasser R ，Goyette G ，Medjahed H ，Perreault J ，Tremblay T ，Lewin A ，Gokool L ，Morrisseau C ，Bégin P ，Tremblay C ，Martel-Laferrière V ，Kaufmann DE ，Richard J ，Bazin R ，Finzi A ... -  《mBio》

Treatment of 5 Critically Ill Patients With COVID-19 With Convalescent Plasma.

Shen C ，Wang Z ，Zhao F ，Yang Y ，Li J ，Yuan J ，Wang F ，Li D ，Yang M ，Xing L ，Wei J ，Xiao H ，Yang Y ，Qu J ，Qing L ，Chen L ，Xu Z ，Peng L ，Li Y ，Zheng H ，Chen F ，Huang K ，Jiang Y ，Liu D ，Zhang Z ，Liu Y ，Liu L ... -  《-》