• connective tissue diseases
• covid-19
• rare diseases
• vccinations

On May 5, 2023, the World Health Organization declared officially the end of the global health emergency caused by SARS-CoV-2; however still today, the virus continues to be present and infect the population, although with a lower risk of developing severe COVID-19 disease than in the past.
This result was achieved thanks to the development of vaccines against SARS-CoV-2. There has been a long debate about their safety and efficacy in the general population and especially in some categories of subjects defined fragile, as they are subjected to a greater risk of infection, hospitalization and death due to the presence of comorbidities and/or due to the intake of immunosuppressive therapies such as in the case of rheumatology patients suffering from rare and complex connective tissue disease (rcCTD).
The European Reference Network on Rare and Complex Connective Tissue and Musculoskeletal Diseases has investigated the long-term effects, in terms of efficacy and safety, of anti-COVID-19 vaccinations in patients through the creation of a multicenter observational study with rcCTD.
This study enrolled 363 rcCTD patients (87% female, mean age 51.8 ± 14.6 years) from 9 ERN ReCONNET centers during the period February 2021-October 2021.
Demographic, clinical and vaccination data were acquired for these patients at the time of enrolment. Follow-up visits were subsequently made at 4, 12, 24, 36 and 48 weeks after completion of the first vaccination course. Data on adverse events, disease exacerbations, and the occurrence of new SARS-CoV-2 infections were collected during these visits.
Overall, 200 patients (55.1%) experienced at least one adverse event, generally mild and in most cases occurring immediately after vaccination.
During the follow-up, 55 disease exacerbations were recorded in 39 patients (10.7%), distributed over the entire observation period, although more frequently within 4 weeks of completing the vaccination cycle.
The incidence of new SARS-CoV-2 infections was 8.9 per 1000 person-months, with no cases within 12 weeks of vaccine administration and a trend of increasing infections away from the primary vaccination course.
During the follow-up, 55 disease exacerbations were recorded in 39 patients (10.7%), distributed over the entire observation period, although more frequently within 4 weeks of completing the vaccination cycle.
The incidence of new SARS-CoV-2 infections was 8.9 per 1000 person-months, with no cases within 12 weeks of vaccine administration and a trend of increasing infections away from the primary vaccination course.
Only one case of severe COVID-19 was reported during the study period.
COVID-19 vaccination appears effective and safe in patients with rcCTD.
The rate of new infections was quite low, and serious infections were rare in our cohort.
We have not observed an increased risk of disease exacerbations compared to previous disease history; however, such exacerbations can be potentially serious, underscoring the need for close monitoring of our patients.