Third COVID-19 Vaccine Dose Boosts Neutralizing Antibodies in Poor Responders

2021 ◽  
Author(s):  
Douglas Lake ◽  
Alexa Roeder ◽  
Maria Gonzalez-Moa ◽  
Megan Koehler ◽  
Erin Kaleta ◽  
...  
Keyword(s):  
High Risk ◽  
Neutralizing Antibodies ◽  
Vaccine Dose ◽  
Neutralizing Antibody ◽  
Fold Increase ◽  
Poor Responders ◽  
Healthy Individuals ◽  
Vaccine Responses ◽  
Rna Vaccine

Abstract Background While evaluating COVID-19 vaccine responses using a rapid neutralizing antibody (NAb) test, we observed that 25% of RNA vaccine recipients did not neutralize >50%. We termed this group “vaccine poor responders” (VPRs). The objective of this study was to determine if individuals who neutralized <50% would remain VPRs, or if a third dose would elicit high levels of NAbs. Methods 269 healthy individuals ranging in age from 19 to 80 (Average age = 51; 165 females and 104 males) who received either BNT162b2 (Pfizer) or mRNA1273 (Moderna) vaccines were evaluated. NAb levels were measured: i) 2-4 weeks after a second vaccine dose, ii) 2-4 months after the second dose, iii) within 1-2 weeks prior to a third dose and iv) 2-4 weeks after a third RNA vaccine dose. Results Analysis of vaccine recipients revealed that 25% did not neutralize above 50% (Median neutralization = 21%, titers <1:80) within a month after their second dose. Twenty-three of these VPRs obtained a third dose of either BNT162b2 or mRNA-1273 vaccine 1-8 months (average = 5 months) after their second dose. Within a month after their third dose, VPRs showed an average 20-fold increase in NAb levels (range: 46%-99%). Conclusions The results suggest that VPRs are not permanently poor responders; they can generate high NAb levels with an additional vaccine dose. Although it is not known what levels of NAbs protect from infection or disease, those in high-risk professions may wish to keep peripheral NAb levels high, limiting infection, and potential transmission.

scholarly journals Third COVID-19 Vaccine Dose Boosts Neutralising Antibodies in Poor Responders

2021 ◽  
Author(s):  
Douglas F. Lake ◽  
Alexa J. Roeder ◽  
Maria J. Gonzalez-Moa ◽  
Megan Koehler ◽  
Erin Kaleta ◽  
...  
Keyword(s):  
Vaccine Dose ◽  
Fold Increase ◽  
Poor Responders ◽  
Healthy Individuals ◽  
Neutralising Antibodies ◽  
Medical Institutions ◽  
Vaccine Manufacturer ◽  
Clinical Protection ◽  
Study Participants

ABSTRACTObjectiveTo determine if poor responders to COVID-19 RNA vaccines (<50% neutralisation) after two doses would remain poor responders, or if a third dose could elicit high levels of NAbs.DesignClinical follow-up studySettingAcademic and medical institutions in USAParticipants269 healthy individuals ranging in age from 19 to 80 (Average age = 51; 165 females and 104 males) who received either BNT162b2 (Pfizer) or mRNA1273 (Moderna) vaccines.Main Outcome MeasuresNAb levels were measured: i) 2-4 weeks after a second vaccine dose, ii) 2-4 months after the second dose, iii) within 1-2 weeks prior to a third dose and iv) 2-4 weeks after a third RNA vaccine dose.ResultsIn 269 study participants, percent neutralisation ranged from 0% to 99% 2-4 weeks after a second vaccine dose. The majority of vaccine recipients (154/269, 57%) demonstrated NAb levels at ≥75% 2-4 weeks after their second dose. Our study also revealed that 25% of vaccine recipients did not neutralise above 50% (Median neutralisation = 21%, titers <1:80) within a month after their second dose. We called these individuals “vaccine poor responders” (VPRs). Twenty-three VPRs ranging in age from 31 to 79 (10 males, 13 females, average age = 62.5) independently obtained a third dose of either BNT162b2 or mRNA-1273 vaccine 1-8 months (average = 5 months) after their second dose. Within a month after their third dose, poor responders showed an average 20-fold increase in NAb levels (range 46%-99%).ConclusionsThe results suggest that poor responders are not permanently poor responders; they can generate high NAb levels with an additional vaccine dose–independent of mRNA vaccine manufacturer. Previous reports indicate that NAb levels decline much more rapidly than clinical protection from hospitalisation and disease, but that does not account for vaccine recipients who never generated high levels of NAbs after two doses. It is possible that poor responders are a source of breakthrough infections. Although it is not known what levels of NAbs protect from infection or disease, many vaccine recipients in high-risk professions may wish to keep peripheral NAb levels high, limiting infection, asymptomatic viral replication, and potential transmission.

scholarly journals Neutralizing Antibody Therapeutics for COVID-19

Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 628
Author(s):  
Aeron C. Hurt ◽  
Adam K. Wheatley
Keyword(s):  
High Risk ◽  
Neutralizing Antibodies ◽  
Controlled Trial ◽  
Antiviral Treatment ◽  
Severe Disease ◽  
Neutralizing Antibody ◽  
Supplemental Oxygen ◽  
European Medicines Agency ◽  
Global Public Health ◽  
Public Health Burden

The emergence of SARS-CoV-2 and subsequent COVID-19 pandemic has resulted in a significant global public health burden, leading to an urgent need for effective therapeutic strategies. In this article, we review the role of SARS-CoV-2 neutralizing antibodies (nAbs) in the clinical management of COVID-19 and provide an overview of recent randomized controlled trial data evaluating nAbs in the ambulatory, hospitalized and prophylaxis settings. Two nAb cocktails (casirivimab/imdevimab and bamlanivimab/etesevimab) and one nAb monotherapy (bamlanivimab) have been granted Emergency Use Authorization by the US Food and Drug Administration for the treatment of ambulatory patients who have a high risk of progressing to severe disease, and the European Medicines Agency has similarly recommended both cocktails and bamlanivimab monotherapy for use in COVID-19 patients who do not require supplemental oxygen and who are at high risk of progressing to severe COVID-19. Efficacy of nAbs in hospitalized patients with COVID-19 has been varied, potentially highlighting the challenges of antiviral treatment in patients who have already progressed to severe disease. However, early data suggest a promising prophylactic role for nAbs in providing effective COVID-19 protection. We also review the risk of treatment-emergent antiviral resistant “escape” mutants and strategies to minimize their occurrence, discuss the susceptibility of newly emerging SARS-COV-2 variants to nAbs, as well as explore administration challenges and ways to improve patient access.

scholarly journals Durability of Response to a Third BNT162b2 Vaccine in Adults ≥60 Years

2021 ◽  
Author(s):  
Noa Eliakim Raz ◽  
Amos Stemmer ◽  
Yaara Leibovici-Weissman ◽  
Asaf Ness ◽  
Muhammad Awwad ◽  
...  
Keyword(s):  
Adverse Events ◽  
Neutralizing Antibodies ◽  
Multivariable Analysis ◽  
Vaccine Dose ◽  
Neutralizing Antibody ◽  
Clinical Frailty Scale ◽  
Younger Adults ◽  
The Third ◽  
Antibody Titers ◽  
Level 2

BACKGROUND Age and frailty are strong predictors of COVID-19 mortality. After the second BNT162b2 dose, immunity wanes faster in older (≥65 years) versus younger adults. The durability of response after the third vaccine is unclear. METHODS This prospective cohort study included healthcare workers/family members ≥60 years who received a third BNT162b2 dose. Blood samples were drawn immediately before (T0), 10-19 (T1), and 74-103 (T2) days after the third dose. Antispike IgG titers were determined using a commercial assay, seropositivity was defined as ≥50 AU/mL. Neutralizing antibody titers were determined at T2. Adverse events, COVID-19 infections, and clinical frailty scale (CFS) levels were documented. RESULTS The analysis included 97 participants (median age, 70 years [IQR, 66-74], 61% women, 58% CFS level 2). IgG titers, which increased significantly from T0 to T1 (medians, 440 AU/mL [IQR, 294-923] and 25,429 [14,203-36,114] AU/mL, respectively; P<0.001), decreased significantly by T2, but all remained seropositive (median, 8,306 AU/mL [IQR, 4595-14,701], P<0.001 vs T1). In a multivariable analysis, only time from the first vaccine was significantly associated with lower IgG levels at T2 (P=0.004). At T2, 60 patients were evaluated for neutralizing antibodies; all were seropositive (median, 1,294 antibody titer [IQR, 848-2,072]). Neutralizing antibody and antispike IgG levels were correlated (R=0.6, P<0.001). No major adverse events or COVID-19 infections were reported. CONCLUSIONS Antispike IgG and neutralizing antibodies levels remain adequate 3 months after the third BNT162b2 vaccine in healthy adults ≥60 years, although the decline in IgG is concerning. A third vaccine dose in this population should be top priority.

scholarly journals 2764. Generation of a Balanced, Tetravalent Dengue Vaccine Based on Contemporary Strains Using a Computational, Synthetic Biology-Based Platform

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S975-S975
Author(s):  
Ying Wang ◽  
Charles B Stauft ◽  
Kanakatte Raviprakash ◽  
J Robert Coleman ◽  
Steffen Mueller
Keyword(s):  
Human Cell ◽  
Neutralizing Antibodies ◽  
Vaccine Dose ◽  
Neutralizing Antibody ◽  
Denv Infection ◽  
The United States ◽  
Wild Type ◽  
Lethal Challenge ◽  
Denv Serotypes ◽  
Tetravalent Vaccine

Abstract Background The WHO estimates that there may be 50 million cases of dengue virus (DENV) infection worldwide every year. There is no safe vaccine against DENV licensed in the United States. The development of a balanced and effective anti-DENV vaccine is vital to preventing morbidity and mortality. Codagenix used its proprietary SAVE (Synthetic Attenuated Virus Engineering) platform to generate and test a live attenuated, tetravalent vaccine against DENV. Methods Codagenix used SAVE to substitute under-represented human codons and codon-pairs into the E protein sequences of contemporary strains of DENV1-4, producing either a fully human-cell-deoptimized prM-E (E-Min), or a partially deoptimized prM-E (E-W/Min) to allow for balancing of the vaccine’s immunogenicity. Full genomes containing deoptimized E-Min and E-W/Min in the DENV2 backbone were transfected into cells to recover live-attenuated, human-cell-deoptimized vaccine strains. Mice were vaccinated with 106 FFU of each DENV vaccine (alone or together), boosted on day 21 and assessed for neutralizing antibodies by PRNT50 and survival after lethal challenge with mouse-adapted wild-type (WT) DENV. Cynomolgus macaques were immunized with a mixture of 106 FFU of each DENV vaccine strain. Two doses were administered on study day 1 and 57 and serum neutralizing antibodies were determined on day 57 and 85 by a microneutralization assay. Results SAVE deoptimized DENV viruses grew to wild-type (between 107 and 108 FFU/ml) levels at permissive temperatures (<37C). All vaccine strains generated neutralizing antibody levels comparable to WT. A tetravalent formulation containing all four E-Min strains protected mice from lethal challenge with DENV3. A tetravalent formulation of Codagenix DENV-E-W/Min vaccine elicited a robust and balanced neutralizing antibody response in non-human primates (NHPs) against all four DENV serotypes after a single dose. A second vaccine dose did not boost antibody titers significantly. Conclusion The ability to rationally balance the attenuation of multiple vaccine strains, thereby avoiding antibody-dependent enhancement, is a unique advantage of the Codagenix SAVE platform. Codagenix DENV vaccine viruses generated balanced, sterilizing immunity in NHPs after one dose. Disclosures All authors: No reported disclosures.

scholarly journals Function is more reliable than quantity to follow up the humoral response to the Receptor Binding Domain of SARS- CoV-2 Spike Protein after Natural Infection or COVID-19 vaccination

2021 ◽  
Author(s):  
Carlos A Sariol ◽  
Petraleigh Pantoja ◽  
Crisanta Serrano-Collazo ◽  
Tiffant Rosa-Arocho ◽  
Albersy Armina ◽  
...  
Keyword(s):  
Immune Response ◽  
Neutralizing Antibodies ◽  
Natural Infection ◽  
Vaccine Dose ◽  
Humoral Response ◽  
Neutralizing Antibody ◽  
Viral Neutralization ◽  
Neutralizing Activity ◽  
Robust Immune Response

On this work we report that despite of a decline in the total anti-Spike antibodies the neutralizing antibodies remains at a similar level for an average of 98 days in a longitudinal cohort of 59 Hispanic/Latino exposed to SARS-CoV-2. We are also reporting that the percentage of neutralization correlates with the IgG titers and that in the first collected samples, IgG1 was the predominant isotype (62.71%), followed by IgG4 (15.25%), IgG3 (13.56%), and IgG2 (8.47%) during the tested period. The IgA was detectable in 28.81% of subjects. Only 62.71% of all subjects have detectable IgM in the first sample despite of confirmed infection by a molecular method. Our data suggests that 100% that seroconvert make detectable neutralizing antibody responses measured by a surrogate viral neutralization test. We also found that the IgG titers and neutralizing activity were higher after the first dose in 10 vaccinated subjects out of the 59 with prior infection compare to a subgroup of 21 subjects naive to SARS-CoV-2. One dose was enough but two were necessary to reach the maximum percentage of neutralization in subjects with previous natural infection or naive to SARS-CoV-2 respectively. Like the pattern seen after the natural infection, after the second vaccine dose, the total anti-S antibodies and titers declined but not the neutralizing activity which remains at same levels for more than 80 days after the first vaccine dose. That decline, however, was significantly lower in pre-exposed individuals which denotes the contribution of the natural infection priming a more robust immune response to the vaccine. Also, our data indicates that the natural infection induces a more robust humoral immune response than the first vaccine dose in unexposed subjects. However, the difference was significant only when the neutralization was measured but not by assessing the total anti-S antibodies or the IgG titers. This work is an important contribution to understand the natural immune response to the novel coronavirus in a population severely hit by the virus. Also provide an invaluable data by comparing the dynamic of the immune response after the natural infection vs. the vaccination and suggesting that a functional test is a better marker than the presence or not of antibodies. On this context our results are also highly relevant to consider standardizing methods that in addition to serve as a tool to follow up the immune response to the vaccines may also provide a correlate of protection.

scholarly journals Safety and immunogenicity of inactivated SARS-CoV-2 vaccine in high-risk occupational population: a randomized, parallel, controlled clinical trial

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Yongliang Feng ◽  
Jing Chen ◽  
Tian Yao ◽  
Yue Chang ◽  
Xiaoqing Li ◽  
...  
Keyword(s):  
Clinical Trial ◽  
High Risk ◽  
Neutralizing Antibodies ◽  
Health Care Systems ◽  
Controlled Trial ◽  
Geometric Mean ◽  
Neutralizing Antibody ◽  
Shanxi Province ◽  
Controlled Clinical Trial ◽  
Clinical Trial Registry

Abstract Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the resulting coronavirus disease 2019 (COVID-19) have a substantial burden on health-care systems around the world. This is a randomized parallel controlled trial for assessment of the immunogenicity and safety of an inactivated SARS-CoV-2 vaccine, aiming to determine an appropriate vaccination interval of the vaccine for high-risk occupational population. Methods In an ongoing randomized, parallel, controlled phase IV trial between January and May 2021 in Taiyuan City, Shanxi Province, China, we randomly assigned the airport ground staff and public security officers aged 18 to 59 years to receive two doses of inactivated SARS-CoV-2 vaccine at 14 days, 21 days, or 28 days. The serum neutralizing antibody to live SARS-CoV-2 was performed at baseline and 28 days after immunization. Long-term data are being collected. The primary immunogenicity endpoints were neutralization antibody seroconversion and geometric mean titer (GMT) at 28 days after the second dose. Analysis of variance (ANOVA), chi-square, and logistic regression analysis were used for data analysis. Results A total of 809 participants underwent randomization and received two doses of injections: 270, 270, 269 in the 0–14, 0–21, and 0–28 vaccination group, respectively. By day 28 after the second injection, SARS-CoV-2 neutralizing antibody of GMT was 98.4 (95% CI: 88.4–108.4) in the 0–14 group, which was significantly lower compared with 134.4 (95% CI: 123.1–145.7) in the 0–21 group (P < 0.001 vs 0–14 group) and 145.5 (95% CI: 131.3–159.6) in the 0–28 group (P < 0.001 vs 0–14 group), resulting in the seroconversion rates to neutralizing antibodies (GMT ≥ 16) of 100.0% for all three groups, respectively. The intention-to-treat (ITT) analysis yielded similar results. All reported adverse reactions were mild. Conclusions Both a two-dose of inactivated SARS-CoV-2 vaccine at 0–21 days and 0–28 days regimens significantly improved SARS-CoV-2 neutralizing antibody level compared to the 0–14 days regimen in high-risk occupational population, with seroconversion rates of 100.0%. Trial registration Chinese Clinical Trial Registry, ChiCTR2100041705, ChiCTR2100041706. Registered 1 January 2021, www.chictr.org.cn. Graphical Abstract

scholarly journals Glycosylation of Immunodominant Linear Epitopes in the Carboxy-Terminal Region of the Caprine Arthritis-Encephalitis Virus Surface Envelope Enhances Vaccine-Induced Type-Specific and Cross-Reactive Neutralizing Antibody Responses

2004 ◽  
Vol 78 (17) ◽  
pp. 9190-9202 ◽  
Author(s):  
J. D. Trujillo ◽  
N. M. Kumpula-McWhirter ◽  
K. J. Hötzel ◽  
M. Gonzalez ◽  
W. P. Cheevers
Keyword(s):  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Fold Increase ◽  
Antibody Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Wild Type ◽  
Virus Surface ◽  
Antibody Titers ◽  
Linear Epitopes ◽  
Carboxy Terminal

ABSTRACT This study evaluated type-specific and cross-reactive neutralizing antibodies induced by immunization with modified surface glycoproteins (SU) of the 63 isolate of caprine arthritis-encephalitis lentivirus (CAEV-63). Epitope mapping of sera from CAEV-infected goats localized immunodominant linear epitopes in the carboxy terminus of SU. Two modified SU (SU-M and SU-T) and wild-type CAEV-63 SU (SU-W) were produced in vaccinia virus and utilized to evaluate the effects of glycosylation or the deletion of immunodominant linear epitopes on neutralizing antibody responses induced by immunization. SU-M contained two N-linked glycosylation sites inserted into the target epitopes by R539S and E542N mutations. SU-T was truncated at 518A, upstream from the target epitopes, by introduction of termination codons at 519Y and 521Y. Six yearling Saanen goats were immunized subcutaneously with 30 μg of SU-W, SU-M, or SU-T in Quil A adjuvant and boosted at 3, 7, and 16 weeks. SU antibody titers determined by indirect enzyme-linked immunosorbent assay demonstrated anamnestic responses after each boost. Wild-type and modified SU-induced type-specific CAEV-63 neutralizing antibodies and cross-reactive neutralizing antibodies against CAEV-Co, a virus isolate closely related to CAEV-63, and CAEV-1g5, an isolate geographically distinct from CAEV-63, were determined. Immunization with SU-T resulted in altered recognition of SU linear epitopes and a 2.8- to 4.6-fold decrease in neutralizing antibody titers against CAEV-63, CAEV-Co, and CAEV-1g5 compared to titers of SU-W-immunized goats. In contrast, immunization with SU-M resulted in reduced recognition of glycosylated epitopes and a 2.4- to 2.7-fold increase in neutralizing antibody titers compared to titers of SU-W-immunized goats. Thus, the glycosylation of linear immunodominant nonneutralization epitopes, but not epitope deletion, is an effective strategy to enhance neutralizing antibody responses by immunization.

scholarly journals Ad26.COV2.S protects Syrian hamsters against G614 spike variant SARS-CoV-2 and does not enhance respiratory disease

npj Vaccines ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Joan E. M. van der Lubbe ◽  
Sietske K. Rosendahl Huber ◽  
Aneesh Vijayan ◽  
Liesbeth Dekking ◽  
Ella van Huizen ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Respiratory Disease ◽  
Syrian Hamster ◽  
Neutralizing Antibodies ◽  
Vaccine Dose ◽  
Neutralizing Antibody ◽  
Upper Respiratory Tract ◽  
Syrian Hamsters ◽  
Antibody Titers ◽  
Upper Respiratory

AbstractPreviously we have shown that a single dose of recombinant adenovirus serotype 26 (Ad26) vaccine expressing a prefusion stabilized SARS-CoV-2 spike antigen (Ad26.COV2.S) is immunogenic and provides protection in Syrian hamster and non-human primate SARS-CoV-2 infection models. Here, we investigated the immunogenicity, protective efficacy, and potential for vaccine-associated enhanced respiratory disease (VAERD) mediated by Ad26.COV2.S in a moderate disease Syrian hamster challenge model, using the currently most prevalent G614 spike SARS-CoV-2 variant. Vaccine doses of 1 × 109 and 1 × 1010 VP elicited substantial neutralizing antibodies titers and completely protected over 80% of SARS-CoV-2 inoculated Syrian hamsters from lung infection and pneumonia but not upper respiratory tract infection. A second vaccine dose further increased neutralizing antibody titers that was associated with decreased infectious viral load in the upper respiratory tract after SARS-CoV-2 challenge. Suboptimal non-protective immune responses elicited by low-dose A26.COV2.S vaccination did not exacerbate respiratory disease in SARS-CoV-2-inoculated Syrian hamsters with breakthrough infection. In addition, dosing down the vaccine allowed to establish that binding and neutralizing antibody titers correlate with lower respiratory tract protection probability. Overall, these preclinical data confirm efficacy of a one-dose vaccine regimen with Ad26.COV2.S in this G614 spike SARS-CoV-2 virus variant Syrian hamster model, show the added benefit of a second vaccine dose, and demonstrate that there are no signs of VAERD under conditions of suboptimal immunity.

scholarly journals Antibody Response to the BNT162b2 mRNA COVID-19 Vaccine in Subjects with Prior SARS-CoV-2 Infection

Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 422
Author(s):  
Federico Gobbi ◽  
Dora Buonfrate ◽  
Lucia Moro ◽  
Paola Rodari ◽  
Chiara Piubelli ◽  
...  
Keyword(s):  
Antibody Response ◽  
Neutralizing Antibodies ◽  
Natural Infection ◽  
Vaccine Dose ◽  
Neutralizing Antibody ◽  
Immune Memory ◽  
Effective Response ◽  
Infected People ◽  
Significant Difference ◽  
Antibody Titers

Although antibody levels progressively decrease following SARS-CoV-2 infection, the immune memory persists for months. Thus, individuals who naturally contracted SARS-CoV-2 are expected to develop a more rapid and sustained response to COVID-19 vaccines than naïve individuals. In this study, we analyzed the dynamics of the antibody response to the BNT162b2 mRNA COVID-19 vaccine in six healthcare workers who contracted SARS-CoV-2 in March 2020, in comparison to nine control subjects without a previous infection. The vaccine was well tolerated by both groups, with no significant difference in the frequency of vaccine-associated side effects, with the exception of local pain, which was more common in previously infected subjects. Overall, the titers of neutralizing antibodies were markedly higher in response to the vaccine than after natural infection. In all subjects with pre-existing immunity, a rapid increase in anti-spike receptor-binding domain (RBD) IgG antibodies and neutralizing antibody titers was observed one week after the first dose, which seemed to act as a booster. Notably, in previously infected individuals, neutralizing antibody titers 7 days after the first vaccine dose were not significantly different from those observed in naïve subjects 7 days after the second vaccine dose. These results suggest that, in previously infected people, a single dose of the vaccine might be sufficient to induce an effective response.

scholarly journals Exponential increase in neutralizing and spike specific antibodies following vaccination of COVID-19 convalescent plasma donors

2021 ◽  
Author(s):  
Molly A. Vickers ◽  
Alan Sariol ◽  
Judith Leon ◽  
Alexandra Ehlers ◽  
Aaron V. Locher ◽  
...  
Keyword(s):  
Specific Antibody ◽  
Neutralizing Antibodies ◽  
Case Series ◽  
Neutralizing Antibody ◽  
Fold Increase ◽  
Chemiluminescence Immunoassay ◽  
Specific Antibodies ◽  
Exponential Increase ◽  
Single Vaccination ◽  
Antibody Levels

AbstractBackgroundWith the recent approval of COVID-19 vaccines, recovered COVID-19 subjects who are vaccinated may be ideal candidates to donate COVID-19 convalescent plasma (CCP).Case SeriesThree recovered COVID-19 patients were screened to donate CCP. All had molecularly confirmed COVID-19, and all were antibody positive by chemiluminescence immunoassay (DiaSorin) prior to vaccination. All were tested again for antibodies 11 to 21 days after they received the first dose of the vaccine (Pfizer). All showed dramatic increases (∼50 fold) in spike-specific antibody levels and had at least a 20-fold increase in the IC50 neutralizing antibody titer based on plaque reduction neutralization testing (PRNT). The spike-specific antibody levels following vaccination were significantly higher than those seen in any non-vaccinated COVID-19 subjects tested to date at our facility.ConclusionSpike-specific and neutralizing antibodies demonstrated dramatic increases following a single vaccination post COVID-19 infection which significantly exceeded values seen with COVID-19 infection alone. Recovered COVID-19 subjects who are vaccinated may make ideal candidates for CCP donation.

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