Immunogenicity and Safety of a Three-Dose Sars-Cov-2 Vaccination Strategy in Patients with Immune-Mediated Inflammatory Diseases on Immunosuppressive Therapy

ABSTRACT

Introduction: Humoral vaccine responses to SARS-Cov-2 vaccines are impaired and short lasting in patients with immune-mediated inflammatory diseases (IMID). Concerns have been raised regarding their protection against severe COVID-19 disease. Knowledge regarding efficacy and safety of repeated vaccination in this large patient group is currently lacking. Aims & Methods: The prospective observational Nor-vaC study (NCT04798625) enrolled adult patients on immunosuppressive therapy for inflammatory bowel-and joint diseases. Healthy controls were health care workers from participating hospitals. All participants received standard vaccines according to the national vaccination program with three doses in patients and two doses in controls. The third dose was offered to IMID patients >4 weeks after the second dose. Anti-Spike antibodies were assessed 2-4 weeks, and 12 weeks following each dose. The main outcome was anti-Spike antibody levels 2-4 weeks following three-and two-dose vaccination in patients and controls, respectively. Levels were compared across groups by Mann-Whitney U test. Factors associated with anti-Spike antibody level following the third dose were assessed by uni-and multivariable linear regression adjusted for time between vaccine and sampling. The aim of the study was to evaluate humoral immune responses and safety of repeated vaccination in IMID patients. Result(s) Overall, 1100 patients (156 ulcerative colitis, 217 Crohn's disease, 366 rheumatoid arthritis, 177 spondyloarthritis, and 184 psoriatic arthritis;median age 54 [IQR 42-64];602 women [55%]) and 303 controls (median age 43 [IQR 33-55];226 women [75 %]) were included. Immunosuppressants were tumor necrosis factor inhibitor (TNFi) monotherapy (n=461), TNFi with concomitant immunomodulator (n=254), methotrexate (n=220), vedolizumab (n=46), janus kinase inhibitors (n=33), and other (n=86). Vaccine series were Pfizer BNT162b2 (54% patients, 54% controls), Moderna mRNA-1273 (17% patients, 23% controls), or combination of vaccines (29% patients, 23% controls)). Patients received the third vaccine dose a median of 126 (IQR 105-154) days after the second dose. Following three-dose vaccination, patients achieved median (IQR) antibody levels of 5720 BAU/ml (2138-8732) compared to 4495 (1591-6639) in controls receiving two doses, p=0.27. In patients, anti-Spike antibody levels increased by a median of 1932 BAU/ ml (IQR 150-4978) from the second to the third dose, p<0.001. Factors associated with response were a greater interval between the second and third vaccine dose (>5 months) (p=0.03), vaccination with mRNA-1273 (p<0.001), and a combination of vaccines (p<0.001). Antibody levels had a slower decline-rate following the third vaccine dose, as compared to after the second dose, with a significant difference (p<0.001). Adverse events were reported by 488 (53%) and 464 (47%) patients after second and third dose, respectively, and by 196 (68%) controls. Disease flares were reported by 50 (5%) and 70 (7%) patients following the second and third dose. Conclusion(s) This large observational study shows that additional vaccine doses to IMID patients contributes to strong and sustained immune-responses comparable to healthy persons vaccinated twice. This study highlights the importance of repeated vaccination of IMID patients to ensure a stronger and more durable protection from severe COVID-19.