Rituximab and Covid-19 Vaccines, Are They Fit for Purpose?

ABSTRACT

Background/Aims Since the COVID-19 outbreak the rheumatology community have been concerned about the risk of SARS-CoV-2 infection in patients prescribed immunosuppressing medications. Data suggests that patients receiving Rrtuximab are at increased risk of developing severe outcomes from COVID-19 (1). In our unit all patients receiving rituximab were selected to receive a targeted vaccination and booster programme with all patients receiving at least 2 vaccinations and up to 3 booster vaccinations. We studied the efficacy of the COVID-19 vaccines in rituximab patients, by checking the the Roche Elecsys Anti-SARS-CoV-2-S (Spike) IgG/IgM total antibody levels post vaccination. Our aim was to assess the vaccination response in patients receiving rituximab and to offer advice on continued shielding or alternatively passive immunization with tixagevimab/cilgavimab in those patients who did not mount a response. Methods Taking 39 patients currently on rituximab therapy, we measured Anti- SARS-CoV-2-S (Spike) antibody levels post vaccination. We recorded whether the test was positive or negative, and the numerical result. We recorded rituximab dates of administration and dates of vaccines. We also recorded diagnosis, co-prescribed DMARDs, immunoglobulin levels, white cell and lymphocyte counts. We took record of whether or not the patient subsequently contracted COVID-19, required a hospital admission, ICU or died. Results Of our 39 patients, 21 had Anti-SARS-CoV-2-S (Spike) antibody levels checked. Of these patients, 7 (33%) had a negative spike protein result. Of the patients with a positive result, 8 (38%) had an antibody level between 0-250U/ML, and only 6 (28.6%) had a level >250U/ML (The manufacturer advises that a level above 0.8U/ML is a positive result). Of patients with a negative result, 1 patient had received 3 vaccines, 5 patients had received 4, and 1 patient had 5. All of the patients had received a vaccine >4 weeks prior to receiving the drug. Two patients were co-prescribed Belimumab, 3 were co-prescribed low-dose methotrexate and 2 were not on additional disease modifying agents. The diagnoses of these patients were, 2 patients with SLE, 4 with SPRA, and 1 MPO Vasculitis. There were no significant findings in lymphocyte count, white cell count or immunoglobulin levels. Conclusion These findings suggest that our current COVID-19 vaccination and booster programme may not provide adequate response in patients receiving rituximab therapy. Despite this being a small cohort, these results show that 33% of patients have not mounted a vaccine response and this is concerning. We suggest that vaccine response should be checked in all patients receiving rituximab therapy and those patients who do not mount a vaccine response should be offered passive immunity and advised of possible additional risks regarding COVID-19 exposure.