Immunocompromised populations are at high risk for severe COVID-19. Vaccine-induced SARS-CoV-2 antibody responses are attenuated in solid organ transplant recipients (SOTRs), and breakthrough infections are more common. Additional SARS-CoV-2 vaccine doses may increase anti-spike antibody titers in some SOTRs, but whether this results in enhanced neutralizing capability, especially versus novel variants of concern (VOCs) that exhibit immune escape and higher infectivity (e.g., the Delta variant), is unclear. Here, we report that a third dose of a SARS-CoV-2 vaccine increases anti-SARS-CoV-2 spike and RBD IgG levels as well as plasma neutralizing capability versus VOCs, including Delta, in some SOTRs. However, anti-spike IgG and neutralizing capability remained significantly reduced compared to fully vaccinated healthy controls. These findings highlight the need for continued study of strategies to improve protection from COVID-19 in immunosuppressed populations as more SARS-CoV-2 VOCs emerge.

Vaccine‐induced SARS‐CoV‐2 antibody responses are attenuated in solid organ transplant recipients (SOTRs) and breakthrough infections are more common. Additional SARS‐CoV‐2 vaccine doses increase anti‐spike IgG in some SOTRs, but it is uncertain whether neutralization of variants of concern (VOCs) is enhanced. We tested 47 SOTRs for clinical and research anti‐spike IgG, pseudoneutralization (ACE2 blocking), and live‐virus neutralization (nAb) against VOCs before and after a third SARS‐CoV‐2 vaccine dose (70% mRNA, 30% Ad26.COV2.S) with comparison to 15 healthy controls after two mRNA vaccine doses. We used correlation analysis to compare anti‐spike IgG assays and focused on thresholds associated with neutralization. A third SARS‐CoV‐2 vaccine dose increased median total anti‐spike (1.6‐fold), pseudoneutralization against VOCs (2.5‐fold vs. Delta), and neutralizing antibodies (1.4‐fold against Delta). However, neutralization activity was significantly lower than healthy controls (p < .001); 32% of SOTRs had zero detectable nAb against Delta after third vaccination compared to 100% for controls. Correlation with nAb was seen at anti‐spike IgG >4 Log10(AU/ml) on the Euroimmun ELISA and >4 Log10(AU/ml) on the MSD research assay. These findings highlight benefits of a third vaccine dose for some SOTRs and the need for alternative strategies to improve protection in a significant subset of this population.

Background The efficacy of COVID-19 convalescent plasma (CCP) is primarily ascribed as a source of neutralizing anti-SARS-CoV-2 antibodies. However, the composition of other immune components in CCP and their potential roles remain largely unexplored. This study aimed to describe the composition and concentrations of plasma cytokines and chemokines in eligible CCP donors. Methods A cross-sectional study was conducted among 20 pre-pandemic healthy blood donors without SARS-CoV-2 infection and 140 eligible CCP donors with confirmed SARS-CoV-2 infection. Electrochemiluminescence detection based multiplexed sandwich immunoassays were used to quantify plasma cytokine and chemokine concentrations (n=35 analytes). A SARS-CoV-2 microneutralization assay was also performed. Differences in the percent detection and distribution of cytokine and chemokine concentrations were examined by categorical groups using Fisher’s exact and Wilcoxon rank-sum tests, respectively. Results Among CCP donors (n=140), the median time since molecular diagnosis of SARS-CoV-2 was 44 days(interquartile range=38-50) and 9%(n=12) were hospitalized due to COVID-19. Compared to healthy blood donor controls, CCP donors had significantly higher plasma levels of IFN-γ, IL-10, IL-15, IL-21 and MCP-1, but lower levels of IL-1RA, IL-8, IL-16, and VEGF-A(P&lt;0.0014). Significant differences were also observed in plasma levels of IL-8, IL-15 and IP-10 between CCP donors with low(&lt;40) vs. high(≥160) anti-SARS-CoV-2 neutralizing antibody titers(P&lt;0.0014). The median levels of IL-6, IL-8, TNF-α, IL-12/IL23p40, MDC were significantly higher among CCP donors who were hospitalized vs. non-hospitalized(P&lt;0.05). Conclusion Heterogeneity in cytokine and chemokine composition of CCP suggests there is a different inflammatory state among the CCP donors as compared to SARS-CoV-2 naïve, healthy blood donors.

Oral fluid (hereafter saliva) offers a non-invasive sampling method for the detection of SARS-CoV-2 antibodies. However, data comparing performance of salivary tests against commercially-available serologic and neutralizing antibody (nAb) assays are lacking. This study compared the performance of a multiplex salivary SARS-CoV-2 IgG assay targeting antibodies to nucleocapsid (N), receptor binding domain (RBD) and spike (S) antigens to three commercially-available SARS-CoV-2 serology enzyme immunoassays (EIAs) (Ortho Vitros, Euroimmun, and BioRad) and nAb. Paired saliva and plasma samples were collected from 101 eligible COVID-19 convalescent plasma (CCP) donors >14 days since PCR+ confirmed diagnosis. Concordance was evaluated using positive (PPA) and negative (NPA) percent agreement, overall percent agreement (PA), and Cohen’s kappa coefficient. The range between salivary and plasma EIAs for SARS-CoV-2-specific N was PPA: 54.4-92.1% and NPA: 69.2-91.7%, for RBD was PPA: 89.9-100% and NPA: 50.0-84.6%, and for S was PPA: 50.6-96.6% and NPA: 50.0-100%. Compared to a plasma nAb assay, the multiplex salivary assay PPA ranged from 62.3% (N) and 98.6% (RBD) and NPA ranged from 18.8% (RBD) to 96.9% (S). Combinations of N, RBD, and S and a summary algorithmic index of all three (N/RBD/S) in saliva produced ranges of PPA: 87.6-98.9% and NPA: 50-91.7% with the three EIAs and ranges of PPA: 88.4-98.6% and NPA: 21.9-34.4% with the nAb assay. A multiplex salivary SARS-CoV-2 IgG assay demonstrated comparable performance to three commercially-available plasma EIAs and a nAb assay, and may be a viable alternative to assist in screening CCP donors and monitoring population-based seroprevalence and vaccine antibody response.

Blood transfusions are among the most common therapeutic procedures performed in hospitalized patients. This study evaluates contemporary national trends in RBC, plasma, platelet and cryoprecipitate transfusions. National Inpatient Sample (NIS), the largest all-payer inpatient database representing 94-97% of US population, was evaluated from the 4th quarter of 2015 through 2018. Quarterly trends for the percentage of hospitalizations with a transfusion procedure were separately examined for each blood product using log binomial regression and reported as quarterly percent change (QPC). The percentage of hospitalizations with a RBC transfusion decreased from 4.22% (2015Q4) to 3.79% (2018Q4) (QPC=-0.72[95%CI=-1.26, -0.19]; Ptrend=0.008). While plasma transfusions also decreased QPC=-1.33(95%CI=-2.00, 0.65;Ptrend&lt;0.001), platelet transfusions remained stable QPC=-0.13[95%CI=-0.99,0.73]; Ptrend=0.766). In contrast, hospitalizations with cryoprecipitate utilization significantly increased QPC=2.01(95%CI=0.57,3.44; Ptrend=0.006). Significant quarterly reductions in RBC transfusions were also seen among many -but not all- strata of sex, race/ethnicity, patient risk-severity, and admission type (elective versus non-elective). Despite significant declines in RBC transfusions among older adults, there were no significant changes among pediatric age-group (&lt;18-years) and those 18-49 years. The decline in RBC and plasma transfusions suggests steady incorporation of robust evidence base showing safety of restrictive transfusions. Increased cryoprecipitate use may be reflective of wider adoption of hypofibrinogenemia management and hemostasis testing for coagulopathic patients.

Background. Solid organ transplant recipients (SOTRs) are at increased risk for severe COVID-19 and exhibit lower antibody responses to SARS-CoV-2 vaccines. This study aimed to determine if prevaccination cytokine levels are associated with antibody response to SARS-CoV-2 vaccination. Methods. A cross-sectional study was performed among 58 SOTRs before and after two-dose mRNA vaccine series, 35 additional SOTRs before and after a third vaccine dose, and comparison to 16 healthy controls (HCs). Antispike antibody was assessed using the IgG Euroimmun ELISA. Electrochemiluminescence detection-based multiplexed sandwich immunoassays (Meso Scale Diagnostics) were used to quantify plasma cytokine and chemokine concentrations (n = 20 analytes) and compare concentrations between SOTRs and HCs, stratified by ultimate antibody response to the vaccine using Wilcoxon-rank-sum test with false discovery rates computed to correct for multiple comparisons. Results. In the study population, 100% of HCs, 59% of SOTRs after 2 doses and 63% of SOTRs after 3 doses had a detectable antibody response. Multiple baseline cytokines were elevated in SOTRs versus HCs. There was no significant difference in baseline cytokine levels between SOTRs with high versus low-titer antibodies after 2 doses of vaccine. However, as compared with poor antibody responders, SOTRs who went on to develop a high-titer antibody response to a third dose of vaccine had significantly higher prethird dose levels of several innate immune cytokines including IL-17, IL-2Ra, IL-6, IP-10, MIP-1α, and TNF-α (false discovery rates < 0.05). Conclusions. A specific inflammatory profile may be associated with developing higher antibodies in response to a third dose of SARS-CoV-2 vaccine in SOTRs.

Oral fluid (hereafter saliva) offers a non-invasive sampling method for detection of SARS-CoV-2 antibodies. However, data comparing performance of salivary tests against commercially-available serologic and neutralizing antibody (nAb) assays are lacking. This study compared the performance of a laboratory-developed multiplex salivary SARS-CoV-2 IgG assay targeting antibodies to nucleocapsid (N), receptor binding domain (RBD) and spike (S) antigens to three commercially-available SARS-CoV-2 serology enzyme immunoassays (EIAs) (Ortho Vitros, Euroimmun, and BioRad) and nAb. Paired saliva and plasma samples were collected from 101 eligible COVID-19 convalescent plasma (CCP) donors >14 days since PCR+ confirmed diagnosis. Concordance was evaluated using positive (PPA) and negative (NPA) percent agreement, and Cohen's kappa coefficient. The range between salivary and plasma EIAs for SARS-CoV-2-specific N was PPA: 54.4-92.1% and NPA: 69.2-91.7%, for RBD was PPA: 89.9-100% and NPA: 50.0-84.6%, and for S was PPA: 50.6-96.6% and NPA: 50.0-100%. Compared to a plasma nAb assay, the multiplex salivary assay PPA ranged from 62.3% (N) and 98.6% (RBD) and NPA ranged from 18.8% (RBD) to 96.9% (S). Combinations of N, RBD, and S and a summary algorithmic index of all three (N/RBD/S) in saliva produced ranges of PPA: 87.6-98.9% and NPA: 50-91.7% with the three EIAs and ranges of PPA: 88.4-98.6% and NPA: 21.9-34.4% with the nAb assay. A multiplex salivary SARS-CoV-2 IgG assay demonstrated variable, but comparable performance to three commercially-available plasma EIAs and a nAb assay, and may be a viable alternative to assist in monitoring population-based seroprevalence and vaccine antibody response.

Data from the National Inpatient Sample demonstrate that methicillin-resistant Staphylococcus aureus (MRSA)–related septicemia hospitalizations increased from 1.67 (95% CI, 1.63–1.72) to 1.94 (95% CI, 1.88–2.00; Ptrend &lt; .001) discharges per 1000 hospitalizations between 2016 and 2019. Regionally, the trends were similar. Rates of MSSA-related septicemia and pneumonia hospitalizations also increased significantly over this time period.