NoV epidemics resulted from the global spread of GII.4 strains that evolved under the influence of population immunity. Lineages show notable (and currently unexplained) differences in geographic prevalence. Establishing a global NoV network by which data on strains with the potential to cause pandemics can be rapidly exchanged may lead to improved prevention and intervention strategies.

COVID‐19 is associated with increased morbidity and mortality in transplant recipients. There are no efficacy data available regarding these patients with any of the available SARS‐CoV‐2 vaccines. We analyzed the humoral response following full vaccination with the BNT162b2 (Pfizer‐BioNTech) in 136 kidney transplant recipients, and compared it to 25 controls. In order to exclude prior exposure to the virus, only participants with negative serology to SARS‐CoV‐2 nucleocapsid protein were included. All controls developed a positive response to spike protein, while only 51 of 136 transplant recipients (37.5%) had positive serology (p < .001). Mean IgG anti‐spike level was higher in the controls (31.05 [41.8] vs. 200.5 [65.1] AU/mL, study vs. control, respectively, p < .001). Variables associated with null humoral response were older age (odds ratio 1.66 [95% confidence interval 1.17–2.69]), high‐dose corticosteroids in the last 12 months (1.3 [1.09–1.86]), maintenance with triple immunosuppression (1.43 [1.06–2.15]), and regimen that includes mycophenolate (1.47 [1.26–2.27]). There was a similar rate of side effects between controls and recipients, and no correlation was found between the presence of symptoms and seroconversion. Our findings suggest that most kidney transplant recipients remain at high risk for COVID‐19 despite vaccination. Further studies regarding possible measures to increase recipient's response to vaccination are required.

Background and aims Two SARS-CoV-2 mRNA vaccines were approved to prevent COVID-19 infection, with reported vaccine efficacy of 95%. Liver transplant (LT) recipients are at risk for lower vaccine immunogenicity and were not included in the registration trials. We assessed vaccine immunogenicity and safety in this special population. Methods LT recipients followed at the Tel-Aviv Sourasky Medical Center and healthy volunteers were tested for SARS-CoV-2 IgG antibodies directed against the Spike-protein (S) and Nucleocapsid-protein (N) 10-20 days after receiving the second Pfizer-BioNTech BNT162b2 SARS-CoV-2 vaccine dose. Information regarding vaccine side effects and clinical data was collected from patients and medical records. Results Eighty LT recipients were enrolled. Mean age was 60 years and 30% were female. Twenty-five healthy volunteer controls were younger (mean age 52.7 years, p=0.013) and mostly female (68%, p=0.002). All participants were negative for IgG N-protein serology, indicating immunity did not result from prior COVID-19 infection. All controls were positive for IgG S-protein serology. Immunogenicity among LT recipients was significantly lower with positive serology in only 47.5% (p<0.001). Antibody titer was also significantly lower in this group (mean 95.41 AU/mL vs. 200.5 AU/mL in controls, p<0.001). Predictors for negative response among LT recipients were older age, lower eGFR, and treatment with high dose steroids and MMF. No serious adverse events were reported in both groups. Conclusion LT recipients developed substantially lower immunological response to Pfizer-BioNTech SARS-CoV-2 mRNA-based vaccine. Factors influencing serological antibodies response include age, renal function and immunosuppressive medications. The findings require re-evaluation of vaccine regimens in this population. Lay summary Liver Transplant recipients had a substantially inferior immunity to the Pfizer-BioNTech BNT162b2 SARS-CoV-2 vaccine. Less than half of the patients developed sufficient levels of antibodies against the virus, and in those who were positive , average antibody levels were two times less compared to healthy controls. Factors predicting non-response were older age, renal function and immunosuppressive medications.

Background In mid-December 2020, Israel had started a nationwide mass vaccination campaign against COVID-19. In the first few weeks, medical personnel, elderly citizens and patients with chronic diseases were prioritized. As such, patients with primary and secondary immunodeficiencies were encouraged to receive the vaccine. While the efficacy of RNA-based COVID-19 vaccines was demonstrated in the general population, little is known about their efficacy and safety in patients with Inborn Errors of Immunity (IEI). Objectives To evaluate the humoral and cellular immune response to COVID-19 vaccine in a cohort of IEI patients. Methods 26 adult patients were enrolled, and plasma and peripheral blood mononuclear cells were collected two weeks following the second dose of Pfizer-BioNTech COVID-19 vaccine. Humoral response was evaluated by testing anti-SARS-CoV-2 Spike (S) Receptor Binding Domain (RBD) and anti-Nuclear (N) antibody titers, and evaluation of neutralizing ability by inhibition of RBD:ACE2 binding. Cellular immune response was evaluated by ELISpot, estimating IL2 and IFNγ secretion in response to pooled SARS-CoV-2 S or M peptides. Results Our cohort included 18 patients with predominantly antibody deficiency, 2 with combined immunodeficiency, 3 with immune-dysregulation, and 3 with other genetically defined diagnoses. 22/26 were receiving immunoglobulin replacement therapy. 18/26 developed specific antibody response and 19/26 showed S-peptide specific T-cell response. None of the patients reported significant adverse events. Conclusion Vaccinating IEI patients is safe, and most patients were able to develop vaccine specific antibody response, S-protein specific cellular response or both.