P-147: COVID-19, impact of vaccination in myeloma patients

The worldwide COVID-19 pandemic represents an unprecedented crisis that affects the entire medical community, and appears to be a devastating infection in patients with hematological disorders, including myeloma (MM). Vaccination is therefore crucial in this population. Seroconversion after COVID-19 has been shown to be lower in MM patients compared to the general population. The same is expected after vaccination, as different reports have already revealed a lower antibody response after anti-SARS-CoV-2 vaccination in this group. We investigated the role of anti-SARS-CoV-2 vaccination in our MM patients. We collected data on the occurrence and outcome of COVID-19, and impact of anti-SARS-CoV-2 vaccination in patients with MM or related disorders, excluding MGUS. Diagnosis of COVID-19 relied on a positive RT-PCR nasopharyngeal swab, while immunization was assessed after two shots of either a mRNA (Pfizer®/Moderna®) or a viral vector (Astra Zeneca®) vaccine, using the Elecsys immunoassay (Roche®) that measures anti-SARS-CoV-2 antibodies including IgG. From March 2020 to date, 219 patients with plasma cell dyscrasias were seen on a regular basis at our outpatient facility. Only 15 of them were diagnosed with COVID-19 (median age 71, range 55-85), with an adverse outcome occurring in 3 patients with an advanced disease. We then collected the serological status at day 30, of the first 129 patients that completed vaccination. 97 were affected by MM, 19 by SMM, 3 by MGRS, 10 by AL amyloidosis. 118 developed regular antibodies confirmed by the presence of the receptor binding domain of the spike protein (RBD) antibodies, while 7 presented nucleocapsid protein (N) antibodies, suggesting a previous contact with the virus in the absence of any clinical manifestation. 11 patients failed to develop any immunization, all had received immunosuppressive therapies (renal transplantation in 1, long-term corticosteroid in 1, cyclophosphamide in 7, anti-CD20 monoclonal antibodies in 2) or multiple previous lines of therapies. We could not identify any link with immunoparesis or CD4/CD8 levels, additional tests are pending. With a 3 month median follow up, only 1 patient experienced a mild form of COVID-19 after vaccination despite high levels of neutralizing antibodies. So far, SARS-CoV-2 vaccination provides an adequate coverage in our MM population since only one case of COVID-19 occurred after vaccination. Extended follow-up will however be needed to confirm this, particu