TY - JOUR T1 - Breakthrough infection after three doses of COVID-19 mRNA vaccine in systemic autoimmune rheumatic diseases: two cases in patients on TNF inhibitor monotherapy JF - RMD Open JO - RMD Open DO - 10.1136/rmdopen-2021-002082 VL - 8 IS - 1 SP - e002082 AU - Kathleen MM Vanni AU - Naomi J Patel AU - Michael DiIorio AU - Emily Kowalski AU - Grace Qian AU - Claire E Cook AU - Susan Y Ritter AU - Zachary S Wallace AU - Jeffrey A Sparks Y1 - 2022/02/01 UR - http://rmdopen.bmj.com/content/8/1/e002082.abstract N2 - Despite COVID-19 vaccination, immunocompromised patients may be particularly susceptible to SARS-CoV-2 breakthrough infections,1 defined by the US Centers for Disease Control and Prevention (CDC) as positive test results 14 or more days after initial vaccine series completion (https://www.cdc.gov/vaccines/COVID-19/health-departments/breakthrough-cases.html). On 13 August 2021, the US Food and Drug Administration and CDC authorised immunocompromised patients to receive a third dose of SARS-CoV-2 mRNA vaccine, defining this as the completion of their initial series (rather than a ‘booster’). Studies have evaluated breakthrough infections in patients with systemic autoimmune rheumatic diseases (SARDs) after the second but not third dose of mRNA (messenger ribonucleic acid) vaccine.2 3 Therefore, we aimed to provide an early description of two cases of breakthrough infections occurring after three mRNA vaccine doses.Mass General Brigham (MGB) is a large, multicentre healthcare system in the greater Boston, Massachusetts area. As previously described,4 we systematically identify all patients with SARDs at MGB with confirmed COVID-19 (by PCR or antigen testing). As of 25 October 2021, we identified two cases of breakthrough infections at least 14 days after receipt of three … ER -