Impact of COVID-19 and vaccination campaign on 1,755 systemic sclerosis patients during first three years of pandemic. Possible risks for individuals with impaired immunoreactivity to vaccine, ongoing immunomodulating treatments, and disease-related lung involvement during the next pandemic phase.

ABSTRACT

Introduction: The impact of COVID-19 pandemic represents a serious challenge for 'frail' patients' populations with inflammatory autoimmune systemic diseases such as systemic sclerosis (SSc). We investigated the prevalence and severity of COVID-19, as well the effects of COVID-19 vaccination campaign in a large series of SSc patients followed for the entire period (first 38 months) of pandemic. Patients and method: This prospective survey study included 1755 unselected SSc patients (186 M, 1,569F; mean age 58.7 ± 13.4SD years, mean disease duration 8.8 ± 7.3SD years) recruited in part by telephone survey at 37 referral centers from February 2020 to April 2023. The following parameters were carefully evaluated i. demographic, clinical, serological, and therapeutical features; ii. prevalence and severity of COVID-19; and iii. safety, immunogenicity, and efficacy of COVID-19 vaccines. Results: The prevalence of COVID-19 recorded during the whole pandemic was significantly higher compared to Italian general population (47.3 % vs 43.3 %, p < 0.000), as well the COVID-19-related mortality (1.91 % vs 0.72 %, p < 0.001). As regards the putative prognostic factors of worse outcome, COVID-19 positive patients with SSc-related interstitial lung involvement showed significantly higher percentage of COVID-19-related hospitalization compared to those without (5.85 % vs 1.73 %; p < 0.0001), as well as of mortality rate (2.01 % vs 0.4 %; p = 0.002). Over half of patients (56.3 %) received the first two plus one booster dose of vaccine; while a fourth dose was administered to 35.6 %, and only few of them (1.99 %) had five or more doses of vaccine. Of note, an impaired seroconversion was recorded in 25.6 % of individuals after the first 2 doses of vaccine, and in 8.4 % of patients also after the booster dose. Furthermore, the absence of T-cell immunoreactivity was observed in 3/7 patients tested by QuantiFERON® SARSCoV-2 Starter Set (Qiagen). The efficacy of vaccines, evaluated by comparing the COVID-19-related death rate recorded during pre- and post-vaccination pandemic periods, revealed a quite stable outcome in SSc patients (death rate from 2.54 % to 1.76 %; p = ns), despite the significant drop of mortality observed in the Italian general population (from 2.95 % to 0.29 %; p < 0.0001). Conclusions: An increased COVID-19 prevalence and mortality rate was recorded in SSc patients; moreover, the efficacy of vaccines in term of improved outcomes was less evident in SSc compared to Italian general population. This discrepancy might be explained by concomitant adverse prognostic factors increased rate of non-responders to vaccine in SSc series, low percentage of individuals with four or more doses of vaccine, ongoing immunomodulating treatments, disease-related interstitial lung disease, and/or reduced preventive measures in the second half of pandemic. A careful monitoring of response to COVID-19 vaccines together with adequate preventive/therapeutical strategies are highly recommendable in the near course of pandemic in this frail patients' population.