This is a summary, written by members of the CITF Secretariat, of:

Cheung MW, Dayam RM, Law JC, Goetgebuer RL, Chao GYC, Finkelstein N, Stempak JM, Pereira D, Croitoru D, Acheampong L, Rizwan S, Lee JD, Ganatra D, Law R, Delgado-Brand M, Mailhot G, Piguet V, Silverberg MS, Watts TH, Gingras A-C, Chandran V. Third dose corrects waning immunity to SARS-CoV-2 mRNA vaccines in immunocompromised patients with immune-mediated inflammatory diseases. RMD Open. doi:. 10.1136/rmdopen-2022-002622

The results and/or conclusions contained in the research do not necessarily reflect the views of all CITF members.

In a letter published in RMD Open, CITF-funded researchers found that SARS-CoV-2 antibody levels and T cell responses increased following a third dose of vaccine in immunocompromised patients. Drs. Vinod Chandran, Anne-Claude Gingras, and Tania Watts (University of Toronto) showed that 92% of COVID-naïve patients with immune-mediated inflammatory disease (IMID) showed anti-spike and anti-RBD antibody levels that were greater than convalescent individuals (those recovering from COVID-19 infection). This was following a third dose of the Pfizer or the Moderna vaccine.

Immunocompromised patients being treated with immunosuppressive drugs are at increased risk of adverse outcomes following SARS-CoV-2 infection. Recent studies have shown that antibody levels and T cell responses wane within three months following the second dose of a SARS-CoV-2 vaccine compared with healthy controls.

Key findings:

  • Anti-spike and anti-RBD IgG levels increased following the third dose.
  • T cell responses, measured by interleukin-2 (IL-2) and interleukin-4 (IL-4)The primary function of interleukins is to modulate growth, differentiation, and activation of cells during inflammation and immune responses. , increased following the third dose, with IL-2 being at a higher concentration after the third dose compared to second dose.
  • There were no observed differences in IL-2 and IL-4 levels against the Omicron variant compared to wild-type (original strain of SARS-CoV-2).

This study indicates that the third vaccine dose induces robust antibody and cellular responses in patients with immune-mediated inflammatory diseases, suggesting that it is important to get the vaccine in a timely manner in order to sustain immune protection induced by the second dose.

Blood samples were collected 2-3 weeks after the third dose from 62 patients (with a median age of 40 years old) who were diagnosed with one or more of the following IMIDs: inflammatory bowel disease, psoriasis, psoriatic arthritis, ankylosing spondylitis, rheumatoid arthritis, or hidradenitis suppurativa.

The primary function of interleukins is to modulate growth, differentiation, and activation of cells during inflammation and immune responses.