P413 Antibody response to the COVID-19 ChAdOx1nCov-19 and BNT162b2 vaccines in the immunosuppressed (RESCUE)

Tran, A.P.(1,2);Tassone, D.(3,4);Nossent, J.C.(2,5);Ding, N.S.(3,4);

(1)St John of God Hospital, Wexford Medical Centre, Murdoch, Australia;(2)The University of Western Australia, School of Medicine and Pharmacology, Perth, Australia;(3)St Vincent's Hospital Melbourne, Gastroenterology, Fitzroy, Australia;(4)The University of Melbourne, Faculty of Medicine- Dentistry and Health Sciences, Parkville, Australia;(5)Sir Charles Gairdner Hospital, Department of Rheumatology, Perth, Australia;


Immunocompromised patients are inherently vulnerable to severe outcomes to vaccine preventable infections compared to the general population. This study aims to investigate the impact of immunosuppression on response to the ChAdOx1nCov-19 and BNT162b2 vaccines to better inform vaccination efforts in this cohort.


A three-armed randomised controlled trial was performed. Patients with autoimmune disorders on immunosuppressive therapies and healthy controls were recruited from two sites. Participants receiving immunosuppression were randomly assigned to either withhold or continue treatment contemporaneous to vaccine administration. Serum SARS-Cov2 immunoglobulin assays were performed at baseline and 4-weeks following first and second vaccine doses. Between group comparisons were performed to examine differences in vaccine seroconversion and immunogenicity.


A total of 253 participants of median age 55 years (IQR: 45.5-64) including 193 patients receiving immunosuppression and 60 healthy controls were studied. Immunosuppressed patients were randomly allocated to continue (n=105) or withhold (n=88) treatment. Of those receiving immunosuppression, 27.08%, 40.63% and 32.29% of patients were exposed to cDMARDs, bDMARDs and tsDMARDs respectively while rates of BNT162b (Pfizer) vaccination were 52.33%, 60.67% and 48.33% among the continue, withhold, and control groups respectively. Post-first dose vaccination seroconversion rates were highest among healthy controls (90%) and patients who temporarily withheld immunosuppressants (76.32%) compared to patients continuing treatment (48.24%) p=0.000. Post-second dose vaccination seroconversion rates were 100% in both the control and withhold groups and 86.75% in the continuation (p=0.001). Mean quantitative serum SARS-CoV-2 IgG titres were 8.58 U/ml, 5.11 U/ml and 3.29 U/ml (p=0.0001) between the controls, withhold and continue groups respectively following first vaccination. While post-second vaccination mean serum IgG titres were 96.31 U/ml, 91.86 U/ml, and 49.73 U/ml (p=0.0066) between these groups.


COVID-19 vaccine response in terms of seroconversion and the level of antibody production was highest among healthy controls compared with patients with autoimmune diseases receiving immunosuppression. Temporary cessation of immunosuppressant therapy, contemporaneous to COVID19 vaccination appears to improve vaccine response in this cohort.