Challenges to Vaccination against SARS-CoV-2 in Patients with Immune-Mediated Diseases

Aberrant deployment of the immune response is a hallmark pathogenic feature of se- vere acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-related disease (COVID-19), possibly accounting for high morbidity and mortality, especially in patients with comorbidities, including immune-mediated disorders. Immunisation with SARS-COV-2 vaccines successfully instructs the immune system to limit viral spread into tissues, mitigate COVID-19 manifestations and prevent its most detrimental inflammatory complications in the general population. Patients with immune- mediated diseases have been excluded from vaccine registration trials, foreclosing the acquisition of specific efficacy and safety data. In this review, we aimed to summarise and critically discuss evidence from real-world studies addressing this issue to provide a comprehensive view of the impact of vaccination practices in patients with allergy, autoimmunity or immunodeficiency. We analysed clinical and laboratory data from 34 studies involving more than 13,000 subjects with vari- ous immune disorders who were vaccinated with mRNA- DNA- or inactivated viral particle-based vaccines. These data globally support the safe and effective use of SARS-CoV-2 vaccines in patients with immune-mediated diseases, although patient-tailored strategies to determine vaccination tim- ing, vaccine choice and background therapy management are warranted to optimise vaccination outcomes. More data are needed regarding patients with primary immunodeficiencies.