Immunogenicity of Covishield vaccine in patients with autoimmune rheumatic diseases

The Coronavirus disease 2019 (COVID-19) pandemic has been the biggest threat to humankind during the last 3 years. It has caused the loss of more than 6.9 million precious lives across the world. The only method by which the massacre could be stopped was by mass vaccination or mass immunization. The patients suffering from autoimmune rheumatic disorders (AIRDs) and treated with immunosuppressants were the high-priority candidates for vaccination. However, the data regarding the efficacy of COVID-19 vaccines in this group of patients are very less. Hence, this study was planned to study the immunogenicity of Covishield in patients with AIRDs attending the rheumatology OPD at DMCH, Ludhiana.

It was a prospective cohort study and was planned by the Department of Biochemistry and Department of Clinical Immunology and Rheumatology at Dayanand Medical College and Hospital, Ludhiana. Fifty patients with AIRDs attending the DMCH rheumatology OPD and 52 age and sex-matched healthy controls who had received two doses of Covishield vaccine were included in this study. Patients having any other immunosuppressive conditions like uncontrolled diabetes, hepatitis, malignancy or HIV were excluded. Patients who had suffered from previous laboratory-confirmed COVID-19 infection (by RT-PCR) were also excluded. Blood samples were collected following all aseptic precautions from patients and controls on the 28^th day after administration of a second dose of Covishield vaccine and total antibodies to the severe acute respiratory syndrome coronavirus 2 spike (S) protein receptor binding domain was measured using Elecsys Anti-SARS-CoV-2 S kit from Roche.

It was observed that no significant difference was there in antibody titre between cases and controls (6213 ± 4418 vs. 8331 ± 7979, P = 0.1022). It was also observed that no statistically significant difference in antibody titre in cases without prednisolone and those taking treatment with prednisolone was found (P = 0.7058). A similar observation was found in terms of methotrexate also (P = 0.457). No significant difference in antibody titres was there when compared with controls (for prednisolone, P = 0.169, for methotrexate, P = 0.078). We found that only the patients receiving mycophenolate mofetil showed a statistically significant decrease in antibody titre in comparison to healthy controls (P = 0.03). Our study showed no statistically significant difference in antibody titres between patients suffering from different AIRDs.

Our study supplements the fact that patients with AIRDs in India can receive Covishield as the primary vaccine against COVID-19 without concerns regarding decreased immunogenicity or increased adverse effects.