Third Booster Dose Vaccine against Sars-Cov-2 in Primary Sjogren's Syndrome: Longitudinal Cohort from the Safer Study

ABSTRACT

Objectives: Few studies evaluate the immunogenicity and safety of different COVID-19 vaccine platforms in patients with primary Sjogren's Syndrome (pSS). The present study aims to assess the immunogenicity through anti-spike IgG antibodies after the COVID-19 vaccine dose in heterologous groups compared to homologous regimen in patients with pSS. Method(s) These data are from the SAFER study 'Safety and efficacy of the COVID-19 vaccine in rheumatic disease', a real-life phase IV multicenter longitudinal study, evaluating patients since before the first dose. Pregnant women, those with a history of serious adverse events prior to any vaccine, and those with other causes of immunosuppression were excluded. Patients with pSS > 18 years, classified according to ACR/EULAR 2016 classification criteria were included. Antibodies against the Receptor Binding Domain - RBD portion of the Spike protein of SARS-CoV-2 (IgG-S) were measured by chemiluminescence (Architect SARS-CoV-2 Quanti II, Abbott), before the first dose and 28 days after the 2nd and 3rd dose. Seropositivity was defined as IgG-Spike titers >=7.1 BAU/mL. Patients received adenoviral vector (ChAdOx1, Astrazeneca), mRNA (Pfizer) or inactivated SARS-COV-2 (Coronavac). Non-parametric methods were used. The alpha level of significance was set at 5%. Result(s) 56 participants received 3 doses, 46 +/- 11 years old, disease duration 7.62 years, 92.9% female, 41.1% White and 55.4% Mixed. The homologous third-booster dose group (n = 15, all ChAdOx1) and heterologous group (n = 41) were homogeneous for age, sex, ethnicity, comorbidities, medication and baseline IgG-S median [IQR] titers. After primary vaccination (2 doses) IgG-S median and titers [IQR] were similar in homologous and heterologous groups (373.03 [179.58, 843.92] vs. 473.36 [119.05, 1059.60], p = 0.705). Third-booster dose induced higher IgG-S median [IQR] titers compared to only 2 doses (1229.54 [333.55, 4365.47] vs 464.95 [140.42, 1015.25], p alpha 0.001). Heterologous 3rd-booster induced higher IgG-S median [IQR] titers than homologous scheme with ChAdOx1 (1779.52 [335.83, 4523.89] vs 730.76 [303.37, 1858.98], p = 0.150), Fig 1 and 2, although not statistically significant. Conclusion(s) Third booster dose induced higher humoral immune response compared to two doses whichmay improve protection against COVID-19 in patients with pSS. Although not statistically significant, the response to the heterologous scheme tended to be better than the response to the homologous booster vaccination, which heterologous booster scheme tended to respond better than homologous booster vaccination, which is relevant in this immunosuppressed population. Increasing the sample size will help clarify this issue. .