key: cord-1033976-k62qn9n5 authors: Lake, D.; Roeder, A. J.; Gonzalez-Moa, M. J.; Koehler, M.; Kaleta, E.; Jasbi, P.; Vanderhoof, J.; Mckechnie, D.; Forman, J.; Edwards, B.; Seit-Nebi, A.; Svarovsky, S. title: Third COVID-19 Vaccine Dose Boosts Neutralising Antibodies in Poor Responders date: 2021-12-02 journal: nan DOI: 10.1101/2021.11.30.21266716 sha: 24bc13d6c0f3f0a4398a50e7b388492078d24c45 doc_id: 1033976 cord_uid: k62qn9n5 Objective: To determine if poor responders to COVID19 RNA vaccines (<50% neutralisation) after two doses would remain poor responders, or if a third dose could elicit high levels of NAbs. Design: Clinical follow up study Setting: Academic and medical institutions in USA Participants: 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. Main Outcome Measures NAb levels were measured: i) 2 to4 weeks after a second vaccine dose, ii) 2 to 4 months after the second dose, iii) within 1 to 2 weeks prior to a third dose and iv) 2 to 4 weeks after a third RNA vaccine dose. Results: In 269 study participants, percent neutralisation ranged from 0% to 99% 2 to 4 weeks after a second vaccine dose. The majority of vaccine recipients (154/269, 57%) demonstrated NAb levels at greater than 75% 2 to 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 mRNA1273 vaccine 1 to 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% to 99%). Conclusions The 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. COVID-19 RNA vaccines prevent serious clinical disease requiring hospitalisation in ~95% of vaccine recipients. This suggests that 5% of vaccinated individuals remain susceptible to infection and severe disease (1, 2) . If 300 million people receive two doses of the COVID-19 RNA vaccines, then approximately 15 million people may not be fully protected. Although T cells are important in anti-viral immunity, their activity is difficult to rapidly evaluate at scale. Furthermore, if T cells are engaged, the host is already infected. After natural infection with SARS-CoV-2 or vaccination against COVID-19, anti-viral antibodies are generated by the host. Except for antibodies that mediate antibody-dependent cellular cytotoxicity and complement dependent cytotoxicity, the only antibodies of primary importance are neutralising antibodies (NAbs). NAbs block the spike protein on SARS-CoV-2 from binding to the host cell receptor, angiotensin converting enzyme 2 (ACE2). In particular, the portion of the spike protein that binds to ACE2 is the receptor binding domain (RBD) (3, 4) and there have been many reports of natural, vaccineinduced (5) (6) (7) (8) and therapeutic antibodies(9) that neutralise the virus by binding to the RBD. After 2 doses of either BNT162b2 or mRNA1273, antibodies to spike protein and neutralising antibodies have been quantified in vaccine recipients (1, 2, 10, 11) . Durability of those responses has been reported (12, 13) . Although it is not known what levels of NAbs provide protection against infection and potential disease, some individuals who are high-risk for COVID-19 or those that are caregivers for high-risk individuals may want to keep their NAb levels elevated to avoid asymptomatic infection and potential transmission to vulnerable populations. Since the vaccines do not elicit protective immunity in everyone, many vaccine recipients may want to know how well their vaccine induced protective antibodies and how long they circulate in peripheral blood. NAb levels have been modeled as correlates of protection from infection and/or disease (6) . Here we report the results of a study in which NAb levels were measured in finger-stick whole blood from RNA vaccine recipients at 2-4 weeks and 2-4 months after their second dose, and then again pre and post 3 rd RNA vaccine dose. In this report, we measured NAb levels using a semi-quantitative rapid test (14) in 269 healthy individuals ranging in age from 19 to 80 (Average age = 51; 165 females and 104 males) who received two doses of COVID-19 RNA vaccine. Twenty-three of those study participants received either three doses of BNT162b2 (Pfizer), 3 doses of mRNA-1273 (Moderna) or 2 doses of BNT162b2 followed by a third dose of mRNA-1273. Demographics of this cohort are shown in Table S1 . The aim of this study was to determine if a 3 rd dose of vaccine in VPRs can generate strong neutralising antibodies. Since performing neutralisation assays with authentic SARS-CoV-2 is time-consuming, expensive and requires high-containment facilities with specially trained laboratory personnel, we previously developed a rapid test that semi-quantitatively measures levels of neutralising antibodies in whole blood or serum. The rapid test utilises lateral flow technology and is based on the principle that NAbs of any isotype prevent the receptor binding domain (RBD) on spike protein from binding to ACE2 (Figure 1)(3,4) . Interpretation if the test is counter-intuitive: the weaker the test line, the stronger the neutralising activity. Test and control line densities can be quantified with a lateral flow reader (iDetekt, Austin, TX) and recorded electronically. All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. Interpretation of the rapid test is counter intuitive. A) Methodology overview. Fingerstick blood is transferred to the sample port and followed by two drops chase buffer. Ten minutes later results can be interpreted. Absent or faint test line indicates high NAb levels, while dark or intense test line indicates low/no NAbs. B) Mechanistic schematic. NAbs bind RBD coupled to a green gold nanoshell (GNS) and prevent the RBD/ACE2 interaction from occurring. Abs that bind RBD but do not neutralise allow the RBD/ACE2 interaction to occur, shown as increasingly dark signal as more RBD-GNS/ACE2 binds at the test line. C) Example test showing highly neutralising (top), moderately neutralising (middle), and poorly neutralising antibodies (bottom) within a blood sample. A monoclonal control antibody coupled to a red-GNS runs laterally with the sample/buffer mixture and binds at the control line, seen as a red line. All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. Male and female adults ranging in age from 18-80 years old were recruited with informed consent to measure their NAb levels after vaccination with either BNT162b2 or mRNA1273. The study was approved by the internal review board at Arizona State University. In this cohort, no participant ever tested positive by PCR or was diagnosed with COVID-19 prior to the study. NAb levels were measured in all participants 2 to 4 weeks after a second dose of either BNT162b2 or mRNA1273 vaccine, then tested 2-4 months after dose 2. In those participants who informed us that they had decided to get a third vaccine dose, NAb levels were measured within 2 weeks of receiving dose 3 of either BNT162b2 or mRNA1273 and then measured again 2 to 4 weeks after dose 3. Upon recruitment of participants into the study, we educate them on the difference between any COVID-19 antibody test and a test that semi-quantitatively measures their levels of NAbs (14) . This educational component of the recruitment process has resulted in an overwhelmingly positive response by participants to have their levels of NAbs monitored monthly (subsequent study) and recruitment of their friends and relatives into the study. It seems that people want to know how well the vaccine worked for them and how long NAb levels will last. We explain to participants that no study has yet connected NAb levels with protection from disease. To perform the test, 10ul whole blood from a finger-stick was added to the LFA cassette sample port followed by 60µl (2 drops) of chase buffer. After 10 minutes, densities of both test and control lines were electronically recorded using an iDetekt RDS-2500 density reader. The test leverages the interaction between RBD-conjugated green-gold nanoshells (Nanocomposix) that bind ACE2 at the test line when RBD-neutralising antibodies (RBD-NAbs) are absent or low. Test line density is inversely proportional to RBD-NAbs present within the sample. As a semiquantitative test, the results of the LFA can be interpreted using a scorecard or a lateral flow reader. To support the application of the rapid test to measure NAb levels to SARS-CoV-2, we correlated LFA test line densities with IC50 values obtained in a Focus Reduction Neutralisation Test (FRNT) from 38 serum samples. Test performance was evaluated using a correlation regression analysis of IC50 values and LFA line densities to obtain the equation, Y=-0.7698*X +24.14 when X=log2 IC50 as shown in Supplementary Figure S2 (Figure S1 ). Levene's test was used to assess homoscedasticity between groups prior to significance testing (IBM SPSS Statistics for Macintosh, Version 26.0; Armonk, NY). To account for unequal variances resulting from unequal sample sizes, Welch's t-test with Benjamini-Hochberg false discovery rate (FDR) correction was performed using Microsoft Excel (Version 16.55; Redmond, WA) to evaluate significant differences in mean neutralisation between BNT162b2 (n = 180) and mRNA-1273 (n = 89) 2-4 weeks post-2 nd dose. Cohen's d was calculated using Microsoft Excel. Post-hoc power analysis was computed using G*Power 3.1 software (15) . To support the application of the LFA to measure NAb levels to SARS-CoV-2, we previously reported (14) correlation of LFA test line densities with IC50 values obtained in a Focus All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted December 2, 2021. ; https://doi.org/10.1101/2021.11.30.21266716 doi: medRxiv preprint Reduction Neutralisation Test (FRNT) and demonstrated that the rapid test can accurately and semi-quantitatively measure levels of NAbs directed against SARS-CoV-2. Serum samples with strong neutralising activity demonstrate low line densities while sera with weak neutralising activity demonstrate strong line intensities. Armed with IC50 values, LFA densities and neutralising serum titers from the FRNT, we calculated % neutralisation as: 1-(Test Line Density/Limit of Detection)*100%. Table 1 shows percent neutralisation ranges that correlate to serum titers, FRNT50 values and test line densities. Percent neutralisation was used throughout the study to measure NAb levels in study participants. Supplementary Figure S2 shows actual LFA tests with density values and corresponding IC50s, NAb titers, and percent neutralisation. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted December 2, 2021. ; https://doi.org/10.1101/2021.11.30.21266716 doi: medRxiv preprint NAb levels were measured in 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 using our semi-quantitative rapid test (14) . NAb levels in vaccine recipients were measured at: 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. Several observations were made during this study. Percent neutralisation ranged from 0% to 99% 2-4 weeks after a second dose (Figure 2A) . While our results agree with previous findings in which the majority of vaccine recipients demonstrate NAb levels at ≥75% 2-4 weeks after their second dose (12, 13) , our study also revealed that 25% of vaccine recipients did not neutralise above 50% (Median neutralisation = 21%) within a month after their second dose (Figure 2A) . Twenty-three VPRs ranging in age from 31 to 79 (10 males, 13 females, average age = 62.5, Supplementary Table S1) independently obtained a third dose of either BNT162b2 or mRNA1273 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%) (Figure 2B) , suggesting that most VPRs are not permanently poor responders; they are capable of generating high NAb levels with an additional vaccine dose. All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted December 2, 2021. ; https://doi.org/10.1101/2021.11.30.21266716 doi: medRxiv preprint dose and two to four weeks after a third dose of either BNT162b2 or mRNA-1273. Solid black line is the average % Neutralisation of 3 rd vaccine dose recipients at each time point. At 2-4 weeks post 3 rd dose the average neutralisation was 88%. Separating VPRs in Figure 2A into mRNA1273 and BNT162b2 vaccine recipients unexpectedly revealed that 14% of mRNA1273 recipients were VPRs, while 31% of BNT162b2 recipients were VPRs. Only one of twelve mRNA1273 VPRs chose to receive a third dose of vaccine. In contrast, 23 of 58 BNT162b2 VPRs chose to receive a third dose of either vaccine (see Supplemental Table S1 ) as shown in Supplementary Figure S3 . Statistically, Levene's test indicated heteroscedasticity (p < 0.001), while Welch's t-test showed significant differences in mean neutralisation between groups 2-4 weeks post-2 nd dose (q < 0.001) with medium effect (d = 0.537) and observed power nearing unity (1 -β = 0.981). Some considerations about our findings include the following. We were surprised to observe that 67/269 (25%) of participants in our study did not demonstrate neutralisation >50%. It is not known if poor NAb responders are at increased risk of infection. However, anti-viral T cells and antibodies that mediate ADCC are also important components of immunity and prevent disease once a host is infected. Although 50% neutralisation corresponds to titers <1:160, it is not known if titers of 1:80, for example, would protect an individual from infection. Likewise, it is not known if individuals with highly neutralising antibodies corresponding to titers of ≥1:320 would not be protected from infection. However, some models and reports have predicted that NAb levels can serve as a correlate of protection (6, 17) . The debate about whether a vaccinated individual can transmit virus depends in part on their levels of neutralising antibodies. NAbs prevent infection and are used therapeutically to treat COVID-19 patients (9) . T cells are crucially important for eliminating infected cells (18) (19) (20) , but if anti-viral T cells are engaged, the host is already infected. As NAb levels decrease with time after vaccination, there is an increased likelihood that exposure to SARS-CoV-2 could lead to infection which could potentially lead to transmission (21) . This may be an important point since a significant portion of the population has not been vaccinated and could be infected by a vaccinated individual whose NAb levels are low, such that they do not prevent infection and asymptomatically shed virus just prior to reactivation of immune memory. Twenty-five percent of total participants (n=269) in our study did not generate NAb levels stronger than 50% after a 2-dose regimen. These VPRs ranged in age from 19 to 80 with an average age of 57, median age of 60 (n=67). The age range of non-VPRs was 20 to 80 with an average age of 50, median age of 51 (n=202). Further studies could be performed to determine the relationship of age and poor response to COVID-19 vaccination. Our data suggest that COVID-19 vaccine strategies might follow at least a 3-dose regimen to keep peripheral NAb levels high, limiting infection, asymptomatic viral replication, and potential transmission. It also suggests that NAb levels in vaccine recipients could be evaluated with a rapid test on an individual basis to indicate when an additional dose might be indicated. Although healthcare policy may recommend that a population should receive a third COVID-19 vaccination at a particular time point, an inexpensive rapid test could provide personalised NAb levels on an individual basis to indicate who might or might not require a third dose. Not only would this conserve vaccine, but vaccinating individuals who already have elevated levels of All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted December 2, 2021. ; https://doi.org/10.1101/2021.11.30.21266716 doi: medRxiv preprint NAbs may not provide benefit since spike protein could be cleared by circulating NAbs as fast as it is made by cells. Previous reports indicate that NAb levels decline much more rapidly than protection from hospitalisation and disease, (12, 22) but that does not account for vaccine recipients who never generated high levels of NAbs after two doses. Moreover, it is possible that VPRs could be 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. Although vaccine durability studies indicate an average neutralisation geometric mean titer (GMT) of ≥ 320 during the peak period after 2 nd dose(10,23), the distribution among individual serum samples obtained during the observed peak neutralisation period (4 to 30 days post-2 nd dose) varies greatly (23) . It is unclear what percentage of a population falls below a given GMT or IC50 during the peak neutralisation period following 2 nd dose. Our study supports other findings that majority of healthy individuals generate a NAb response ≥ 75% neutralisation (IC50 ≥160 and <320). However, we highlight a VPR population that, despite healthy status at the time of vaccination, fail to mount a NAb response >50% (IC50 <160) after two doses. Poor NAb titers have been reported in special populations such as patients with ongoing cancer therapies(24), solid organ transplant patients (25) (26) (27) , and individuals on systemic immunosuppressive regimens for various immune-mediate inflammatory diseases (28) . However, current literature is lacking regarding protective antibody responses to COVID-19 in a healthy population. Finally, it is not unprecedented in other vaccine settings such as influenza to observe poor or non-neutralising responses in healthy individuals (29, 30) . Due to the urgency to develop vaccines to slow the COVID-19 pandemic, we are still learning the parameters of RNA vaccine dose, frequency, timing and durability in the human population. This study has several limitations. First, it is still unknown what levels of neutralising antibodies correlate with protection against infection and potential disease. It is possible, but unlikely, that NAb levels as low as 20% could protect against infection (6) . Second, although the N-terminal domain of spike protein also been shown to neutralise SARS-CoV-2, it is currently characterised as a minor component of neutralising antibodies (7, 31) and our test does not detect them. Although we measured NAb levels for twice as many BNT162b2 vaccine recipients as mRNA-1273 recipients, we examined homogeneity of variance using Levene's test and, upon confirming unequal variances, assumed Welch's t-test as a conservative and robust alternative to parametric comparisons of means. Importantly, potential for type I error was mitigated using FDR-adjustment of calculated significance, and Cohen's d showed appreciable effect size between groups. Moreover, post-hoc power analysis showed exceptional sensitivity and low chance of type II error, further supporting the significantly lower percent neutralisation observed in Pfizer recipients 2-4 weeks post-2 nd dose. In conclusion, our findings suggest that 14% of mRNA1273 and 31% of BNT162b2 two-dose vaccine recipients ranging in age from 19 to 80 with an average age of 57 (median age of 60) All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted December 2, 2021. ; https://doi.org/10.1101/2021.11.30.21266716 doi: medRxiv preprint may not have generated levels of NAbs ≥50% and that additional COVID-19 vaccine doses might be indicated for these individuals. Longitudinal studies are ongoing to determine if high NAb levels in recipients of a third vaccine dose are more durable than NAb levels after two doses. What is already known on this topic: • NAb levels and T cell immunity decline after vaccination, but that doesn't account for those vaccine recipients who did not make strong NAb responses after vaccine dose 2. • Mixing and matching vaccines is not harmful. • Most healthy individuals respond to 2 vaccine doses with high NAb titers What this study adds: • Vaccine recipients who did not generate strong NAb responses to the first 2 doses require a third dose to generate high levels of NAbs. • 25% of BNT162b2 vaccine recipients may not know that they do not neutralise SARS-CoV-2 more strongly than 50%. • Strong NAb responses to a third dose of RNA vaccine appear to be independent of manufacturer. Ethical approval: All data generated in this study used finger-stick peripheral blood collected under an Arizona State University institutional review board (IRB) approved protocol #0601000548. Subjects were assigned a vaccine study de-identification number (VAC-ID) at the time of enrollment and all subsequent collections were conducted in compliance with the Collaborative Institutional Training Program (CITI) Human Subjects Research (HSR) regulatory guidance. Data sharing: All de-identified raw data corresponding to results shown as part of the study demonstrated in this manuscript can be made available upon request to corresponding author. Supplementary Figure S1 -Regression analysis of LFA density values and microneutralisation IC50 values. Supplementary Figure S1 . Comparison between LFA density units and IC50 values obtained using convalescent sera isolated from 36 recovered COVID-19 patients. Neutralisation was tested on LFA using 6 µL serum and a dilution series was performed by authentic SARS-CoV-2 FRNT assay to obtain IC50 values. To calculate IC50, data were analyzed in GraphPad Prism 9.0 using methods described by Ferrara and Temperton. Density values and IC50 values were Log2transformed and analyzed using a simple linear regression and nonparametric Spearman correlation with two-tailed P value and a 95% confidence interval (CI). Regression analysis with 95% CI boundaries is indicated in solid black and grey dotted lines. Spearman's rho and twotailed P value are labeled. Y = -0.7698*X + 24.14 -0.7918 r = P < 0.0001 All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted December 2, 2021. Figure S1 . Reciprocal NAb titer is derived from IC50, such that titer is equal to the last dilution factor (DF) (DF =20*2 -n ) for which IC50 is ≥ the lower threshold range for a given titer. For example, IC50=43.8 is classified as an NAb titer of 40. Further, a hypothetical IC50=158 would classify as NAb titer ≥80 and <160. Percent neutralisation was calculated using the equation: 1-(TLD/LoD) when LoD=942,481 as described in Table 1 legend. Test line All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted December 2, 2021. Figure S3 . Comparison of NAbs post-2 nd dose according to vaccine received (mRNA1273 or BNT162b2) ranging from 0% to 99% neutralisation. Data shown as box and whisker plots with black vertical lines that denote upper and lower extremes, and horizontal lines that denote upper and lower quartiles with median at the midline. Median neutralisation of mRNA1273 (n=89) and BNT162b2 (n=180) is 92% and 71%, respectively. Mean neutralisation for mRNA1273 and BNT162b2 groups is 80% and 63%, respectively. Red dots indicate VPRs that received a 3 rd vaccine dose as shown in Figure 2B and described in Supplementary Table S1 . All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted December 2, 2021. ; https://doi.org/10.1101/2021.11.30.21266716 doi: medRxiv preprint Efficacy and Safety of the mRNA-1273 SARS-CoV-2 Vaccine Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine Structural and Functional Basis of SARS-CoV-2 Entry by Using Human ACE2 The receptor binding domain of the viral spike protein is an immunodominant and highly specific target of antibodies in SARS-CoV-2 patients A noncompeting pair of human neutralizing antibodies block COVID-19 virus binding to its receptor ACE2 Neutralizing antibody levels are highly predictive of immune protection from symptomatic SARS-CoV-2 infection Potent neutralizing antibodies from COVID-19 patients define multiple targets of vulnerability Potent human neutralizing antibodies elicited by SARS-CoV-2 infection REGN-COV2, a Neutralizing Antibody Cocktail, in Outpatients with Covid-19 An mRNA Vaccine against SARS-CoV-2 -Preliminary Report COVID-19 vaccine BNT162b1 elicits human antibody and TH1 T cell responses Durability of Responses after SARS-CoV-2 mRNA-1273 Vaccination Antibody Persistence through 6 Months after the Second Dose of mRNA-1273 Vaccine for Covid-19 Development of a Rapid Point-Of-Care Test that Measures Neutralizing Antibodies to SARS-CoV-2. JCV [Internet Power 3: a flexible statistical power analysis program for the social, behavioral, and biomedical sciences Limit of Blank, Limit of Detection and Limit of Quantitation Neutralizing Antibodies Correlate with Protection from SARS-CoV-2 in Humans during a Fishery Vessel Outbreak with a High Attack Rate Targets of T Cell Responses to SARS-CoV-2 Coronavirus in Humans with COVID-19 Disease and Unexposed Individuals SARS-CoV-2-specific T cell immunity in cases of COVID-19 and SARS, and uninfected controls Robust T cell immunity in convalescent individuals with asymptomatic or mild COVID-19 Effect of Vaccination on Household Transmission of SARS-CoV-2 in England Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine through 6 Months Waning Immune Humoral Response to BNT162b2 Covid-19 Vaccine over 6 Months Variable cellular responses to SARS-CoV-2 in fully vaccinated patients with multiple myeloma COVID-19 vaccination in kidney transplant recipients Safety and Immunogenicity of Anti-SARS-CoV-2 Messenger RNA Vaccines in Recipients of Solid Organ Transplants Poor Antibody Response After Two Doses of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Vaccine in Transplant Recipients SARS-CoV-2 vaccination responses in untreated, conventionally treated and anticytokine-treated patients with immune-mediated inflammatory diseases Primary vaccine failure to routine vaccines: Why and what to do? Human Vaccines & Immunotherapeutics Immunogenicity and protective efficacy of influenza vaccination. Virus Research A neutralizing human antibody binds to the N-terminal domain of the Spike protein of SARS-CoV-2. Science We thank Arizona State University School of Life Sciences and Mayo Clinic Arizona Collaborative Research facilities for their providing the laboratory space and time needed to conduct this study at multiple testing location sites. We thank Empowered Diagnostics for providing the test strips for this study. Table S1 . Age ranges are provided to protect the identities of the individuals in the study.