(C,D) Antibody titers compared by vaccine received. responses are important in viral clearance and for minimizing the severity of COVID-19, particularly in the absence of an effective neutralizing antibody response. 7 Conserved SARS-CoV-2 epitopes recognized by T cells may also provide cross-protection against viral variants that evade antibody neutralization.8 Therefore, we evaluated the magnitude of spike-specific T-cell responses (reported by frequency of antigen-induced interferon- secretion) in KTRs and cohabitants by enzyme-linked immunosorbent spot (ELISpot) assay before vaccination and EIF4G1 after 2 vaccine doses (Determine?1d). In line with previous reports (e.g., Anft correlate of protection from SARS-CoV-2 contamination. In the study cohort, all cohabitants met the threshold for effective serological neutralization, as well as that set for anti-RBD IgG titer. By contrast, only 8.7% of KTRs met at least one of the thresholds. The choice of vaccine did not significantly influence the immune response in KTRs; however, superior IgG titers and serological neutralization were observed in household controls who received BNT162b2 (Supplementary Figures?S1CS4). In light of recent findings of poor real-world effectiveness Tiaprofenic acid of the BNT162b2 and ChAdOx1 vaccines in solid organ transplant recipients, these data provide strong support for ring vaccination of cohabitants to reduce the risk of SARS-CoV-2 contamination.2 The effectiveness of ring vaccination in the real world is likely to depend on additional factors, including vaccination status of the whole household, including children as viable vaccination strategies for children are developed, and the emergence and spread of immune-evasive SARS-CoV-2 variants. With no forthcoming strategy to enhance vaccine immunogenicity in KTRs, and efforts underway to develop booster vaccines against the Omicron variant, priority Tiaprofenic acid booster vaccination of household contacts should be the favored vaccination strategy to safeguard immunocompromised transplant recipients. Disclosure All the authors declared no competing interests. Acknowledgments This study was funded by project grants from The Hospital Research Foundation Group, Adelaide, Australia. Footnotes Supplementary File (PDF) Supplementary Methods. Figure?S1. Participant age by treatment and vaccine. Differences between groups tested using the 2-tailed Mann-Whitney test. NS, not significant. ???? 0.0001. Physique?S2. AntiCsevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike IgG. (A,B) Antibody titers in close household contacts and kidney transplant recipients at baseline, 3 weeks after dose 1, and 3 weeks after dose 2. (C,D) Antibody titers compared by vaccine received. Differences between groups tested using the 2-tailed Mann-Whitney test. NS, not significant. ? 0.05; ??? 0.001; ???? 0.0001. Physique?S3. Tiaprofenic acid AntiCsevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) humoral Tiaprofenic acid immune response by vaccine. (A,C) AntiCSARS-CoV-2 receptor-binding domain name (RBD) IgG titers in close household contacts (CHCs) and kidney transplant recipients (KTRs) 3 weeks after the second vaccine dose. (B,D) Serological live computer virus neutralization in CHCs and KTRs 3 weeks after the second vaccine dose. Differences between groups tested using the 2-tailed Mann-Whitney test. NS, not significant. ???? 0.0001. Physique?S4. Vaccine-induced antiviral T-cell response. (A,C) Spike-reactive interferon- (IFN-)Csecreting T cells in close household contacts (CHCs) and kidney transplant recipients (KTRs) at baseline and 3 weeks after dose 2. (C,D) Switch in IFN- spot-forming models (SFUs) between baseline and 3 weeks after the second vaccine dose in CHCs and KTRs compared by vaccine received. Differences between groups tested using the 2-tailed Mann-Whitney test. NS, not significant. ???? 0.0001. Supplementary Reference. Supplementary Material Supplementary File (PDF)Click here to view.(1.1M, pdf).