Seroprevalence to SARS-CoV-2 in Patients with Rheumatic Diseases on Disease Modifying Antirheumatic Drugs and /or Immunosuppressive Medications from India: A Multicentric Study

Background: There is an uncertainty regarding the effect of the SARS-CoV-2 infection on patients with chronic rheumatic diseases who are on immunosuppressive drugs. Disease-modifying anti-rheumatic drugs (DMARDs) are immunomodulatory or immunosuppressive. In the current COVID-19 pandemic, it is not clear whether DMARDs are helpful or detrimental. This study was carried out to estimate the pre-vaccination seroprevalence of antibodies to SARS-CoV-2 in patients with a rheumatic disease on DMARDs and/or immunosuppressive drugs and compare them with family controls Methods: A multicentric cross-sectional seroprevalence study were conducted in five different cities of India using convenient sampling. Patients with a diagnosis of rheumatic disease and on DMARDs were included. Relatives of the patients, preferably staying in the same household with no known rheumatic diseases served as controls. Serum IgG antibodies to SARS-CoV-2 Receptor-Binding Domain(RBD) of the spike protein was measured using electrochemiluminescence immunoassay(ECLIA) using the Roche Kit on Cobas system and IgG antibodies to nucleoprotein (NP) were assayed using chemiluminescent magnetic assay using Abott kit on ARCHITECT system. Findings: Eight hundred ninety-five sera (cases=378 and controls=517) were assayed for detection of antibodies to SARS-CoV-2. IgG antibodies to either RBD and/or NP were positive in 135 (36%) cases as compared to 196 (38%) in controls. The seroprevalence to RBD and NP varied between different cities but was not significantly different between cases and controls in Mumbai, Ahmedabad, Bengaluru and Bhubaneswar. However, the occurrence of IgG antibodies to RBD was significantly (p<0.05) lower in cases (28/65;43%) as compared to controls (423/65;65%) in Kolkata, where the positivity rate was lower in connective tissue disease group than in inflammatory arthritis group . Interpretation: Overall, patients with rheumatic diseases on DMARDs have IgG antibodies to RBD and NP of SARS-CoV-2 at a comparable level with that of controls, but the level of antibodies to RBD is lower in patients with connective tissue disease on immunosuppressive drugs in one centre.Trial Registration: The study was registered in the Central Trial Registry of India with reference number CTRI/2020/11028967.Funding: RM and SP; KIMS, Bhubaneswar & ICMR-RMRC, Bhubaneswar.Declaration of Interest: None to declare. Ethical Approval: This study was approved by the ethics committee at Kalinga Institute of Medical Science, Bhubaneswar which served as the nodal centre on behalf of all the participating centres [KIIT/KIMS/IEC/385/2020].