Statistician Data analyst Research Institute of the McGill University Health Centre Montreal, Canada
Background: Persons with immune-mediated inflammatory diseases (IMID) often take medications that may dampen vaccine responses. SUCCEED was funded by the Canadian government’s COVID Immunity Task Force to study COVID vaccination in IMID.
Objectives: To describe serological results post-vaccine, safety, and estimated serological evidence of recent COVID infection.
Methods: From Vancouver, Calgary, Winnipeg, Montreal, Quebec City, Sherbrooke, Toronto, and Hamilton, data and dried blood spots/sera post-COVID vaccination were collected from adults with rheumatoid arthritis, inflammatory bowel disease, ankylosing spondylitis/spondyloarthritis and psoriasis/psoriatic arthritis. We evaluated seropositivity (surpassing 1% false-reporting cut-off) for anti-SmT1/spike or anti-receptor-binding domain (RBD) IgG as indicating successful serologic response to vaccine. Anti-nucleocapsid (N) IgG seropositivity indicated recent infection.
Results: About 60% of the 1031 participants were female; mean age was 54. Pfizer vaccine accounted for 75% of first/second doses, and 66% of third doses. Moderna accounted most of the remainder. The median time between vaccinations was 59 days between first/second, 143 between second/third; 180 between third/fourth; and 157 between fourth/fifth. Serum samples were collected at a median of 40 days after second, 48 after third, and 21 after fourth dose.
Positive serology for anti-SmT1/RBD IgG was present in 95 percent (95% CI 93-97) post-second-dose, 93% (91-95%) post-third dose, and 95% (74-100%) post-fourth dose. Concordance between anti-SmT1 and anti-RBD IgG was 90.8%. Adverse events post-vaccination were uncommon, with few disease flares requiring ED visits. Bell’s Palsy represented one ED visit, with no confirmed Guillain-Barre or transverse myelitis in our preliminary analyses. Over 2021-2022, anti-N positivity (indicating recent infection) was present in 5.8 % of samples, tending to be more common in the post-Omicron months.
Conclusions: The vast majority of individuals with IMID demonstrated positive anti-SmT1/RBD post-second dose, and after additional doses. Relatively few serious adverse events occurred. These data support the potential usefulness of mRNA COVID-19 vaccination in IMID. Ours is the first estimate of the prevalence of recent COVID infections in a large, pan-Canadian IMID sample.
