Pillar 4
Functional Genomics & Structure-Function of VOCs

We previously demonstrated in a JCI insight study that antibody levels and T cell responses in patients with immune-mediated inflammatory diseases (IMIDs) showed a more rapid decrease by 3 months after the 2nd dose of SARS-CoV-2 mRNA vaccine compared to healthy controls, emphasizing that a 3rd dose of vaccine is very important in IMID patients.

In a new study, our team investigated immune responses in patients with IMID following a third dose of the Pfizer or Moderna mRNA vaccine. We collected blood samples 2–4 weeks after the third dose of vaccine from 62 patients. Using an automated enzyme linked immunosorbent assay (ELISA), we determined that antibody levels to the full-length spike and its receptor binding domain are restored following the third dose vaccination. In addition, the third dose of mRNA vaccine corrects the decreased T cell stimulation measured three months after the second dose of the vaccine.  As previously shown with healthy individuals, we saw no differing T cell response to Omicron peptides in comparison to wild-type, indicating that the IMID patients retain T cell immunity to the Omicron variant tested after three doses of the vaccine. Overall, we observed robust humoral and cellular responses in patients with IMID following the third dose of SARS-CoV-2 mRNA vaccine. Further work is ongoing to look at the waning dynamics of the immune response after the third dose and to evaluate the effect of a fourth dose in these patients.

Funding for this study came from Juan and Stefania Speck, the Canadian Institutes of Health Research, the COVID-19 Immunity Task Force and CoVaRR-Net.

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Michelle Cheung, Roya Dayam, Jaclyn Law, Rogier Goetgebuer, Gary Chao, Naomi Finkelstein, Joanne Stempak, Daniel Pereira, David Croitoru, Lily Acheampong, Saima Rizwan, Jenny Lee, Darshini Ganatra, Ryan Law, Melanie Delgado-Brand, Geneviève Mailhot, Vincent Piguet, Mark Silverberg, Tania Watts, Anne-Claude Gingras, Vinod Chandran. Third dose corrects waning immunity to SARS-CoV-2 mRNA vaccines in immunocompromised patients with immune-mediated inflammatory diseases. RMD Open. 2022.08.002622; https://rmdopen.bmj.com/content/rmdopen/8/2/e002622.full.pdf