ABSTRACT
Purpose: Preliminary studies suggest that kidney transplant recipients (KTRs) show diminished humoral responses to SARS-CoV-2 vaccination. Although reports of allograft rejection after SARS-CoV-2 vaccination have been rare, there is no recommended framework for monitoring for potential vaccine-related allograft injury. Here, we describe an approach for longitudinal assessment of immunogenicity and safety of SARS-COV-2 vaccination in KTRs. Method(s): KTRs eligible for SARS-CoV-2 vaccination were identified through medical records, beginning March 12, 2021. Baseline and weekly blood samples were collected for SARS-CoV-2 spike protein antibody titers, dd-cfDNA and gene expression profiling (GEP) for 12 weeks. Donor specific antibody (DSA) testing was performed at baseline, 2 weeks after completion of vaccine doses and at week 12. Antibody response was defined as a 10-fold increase in total binding IgG titers. Result(s): 49 KTRs were identified for analysis. Patient demographics are shown in Table 1. Ten patients (20.4%) demonstrated a spike antibody response post- vaccination. Of responders, 80% (n=8) had a history of COVID-19. The odds ratio for the association of a history of COVID-19 with vaccine response was 18.3 (95% CI 3.2, 105.0, p=0.0005). Median dd-cfDNA levels did not differ between pre- and postvaccination (0.23% versus 0.21% respectively). There was no significant difference between pre- and post-vaccination GEP scores (9.85 versus 10.4 respectively). No patients developed clinically significant DSA, eGFR decline or allograft rejection following vaccination. Conclusion(s): Quantitative antibody responses were strongly associated with a diagnosis of prior SARS-CoV-2 infection. Stability of eGFR, dd-cfDNA, GEP profiles and lack of allosensitization reinforce the safety profile of SARS-CoV-2 vaccination in KTRs. Further studies are needed to better understand immunogenicity in SARSCoV- 2 naive individuals, including whether cellular responses are protective in the absence of humoral responses.
ABSTRACT
Purpose: Correlates of protection for SARS-CoV-2 vaccines are not well-established in kidney transplant recipients(KTRs). Studies have highlighted the importance of neutralizing antibodies(Abs), however data suggests T cell responses may play a secondary role in preventing reinfection. We performed a longitudinal assessment of immunogenicity, T and B cell response in KTRs following SARS-CoV-2 vaccination. Method(s): KTRs eligible for SARS-CoV-2 vaccination from 3/12/21 were enrolled. Baseline and weekly blood samples were collected for routine lab, SARS-CoV-2 spike protein Ab titers and cellular phenotyping for 12 weeks. Ab response was defined as a 10-fold increase in total binding IgG titers. To determine if T cell responses were induced by vaccination, we considered the proportion of activated non-naive CD4+ and CD8+ T cells post-vaccination. Result(s): 49 KTRs were enrolled ( Demographics -Table 1). 10 patients (20.4%) mounted an Ab response following vaccination. A history of COVID-19 was associated with an increased likelihood of developing an Ab response (OR: 18.3, 95% CI 3.2, 105.0, p=0.0005). For non-naive CD8+ T cells, a subset co-expressing CD38+Ki67+ was induced 1 week after the 1st immunization in some SARS-CoV- 2-naiive patients (P=0.12 versus P=0.14 for SARS-CoV-2-experienced adults, Fig 1A/B). For non-naive CD4+ T cells, induction of a subset co-expressing CD38+Ki67+ was observed at 1 week after the 1st immunization for SARS-CoV-2-naive participants (P = 0.09 for SARS-CoV-2-naive, P=0.03 for SARS-CoV-2-experienced adults, Fig 1C/D). For CD8+ and CD4+ T cells, dose 2 stimulated weak induction of the CD38+Ki67+ subset in the SARS-CoV-2-naive patients only (Fig 1A-D). Conclusion(s): Quantitative Ab responses were strongly associated with prior SARS-CoV-2 infection. Activated CD4+ and CD8+ T cell responses were evident in most patients irrespective of history of COVID-19. Further studies are needed to determine whether these activated CD4+ and CD8+ T cell responses were antigenspecific or confer immunity. (Table Presented).
ABSTRACT
CONTEXT: The rapid emergence of COVID-19 could have direct and indirect impacts on food production systems and livelihoods of farmers. From the farming perspective, disruption of critical input availability, supply chains and labor, influence crop management. Disruptions to food systems can affect (a) planting area; and (b) crop yields. OBJECTIVES: To quantify the impacts of COVID-19 on major cereal crop's production and their cascading impact on national economy and related policies. METHODS: We used the calibrated crop simulation model (DSSAT suite) to project the impact of potential changes in planting area and grain yield of four major cereal crops (i.e., rice, maize, sorghum, and millet) in Senegal and Burkina Faso in terms of yield, total production, crop value and contribution to agricultural gross domestic product (GDP). Appropriate data (i.e., weather, soil, crop, and management practices) for the specific agroecological zones were used as an input in the model. RESULTS AND CONCLUSIONS: The simulated yields for 2020 were then used to estimate crop production at country scale for the matrix of different scenarios of planting area and yield change (-15, -10, -5, 0, +5, +10%). Depending on the scenario, changes in total production of four cereals combined at country levels varied from 1.47 M tons to 2.47 M tons in Senegal and 4.51 M tons to 7.52 M tons in Burkina Faso. The economic value of all four cereals under different scenarios ranged from $771 Million (M) to $1292 M in Senegal and from $1251 M to $2098 M in Burkina Faso. These estimated total crop values under different scenarios were compared with total agricultural GDP of the country (in 2019 terms which was $3995 M in Senegal and $3957 M in Burkina Faso) to assess the economic impact of the pandemic on major cereal grain production. Based on the scenarios, the impact on total agricultural GDP can change -7% to +6% in Senegal and - 8% to +9% in Burkina Faso. SIGNIFICANCE: Results obtained from this modeling exercise will be valuable to policymakers and end-to-end value chain practitioners to prepare and develop appropriate policies to cope or manage the impact of COVID-19 on food systems.