Real-World Effectiveness of a Third Dose of mRNA-1273 versus BNT162b2 on Inpatient and Medically Attended COVID-19 among Immunocompromised Adults in the United States

Recent data have shown elevated infection rates in several subpopulations at risk of SARS-CoV-2 infection and COVID-19, including immunocompromised (IC) individuals. Previous research suggests that IC persons have reduced risks of hospitalization and medically-attended COVID-19 with 2 doses of mRNA-1273 (SpikeVax; Moderna) compared to two doses of BNT162b2 (Comirnaty; Pfizer/BioNTech). The main objective of this retrospective cohort study was to compare real-world effectiveness of third doses of mRNA-1273 versus BNT162b2 at multiple time points on occurrence of COVID-19 hospitalization and medically-attended COVID-19 among IC adults in the US. The HealthVerity (HV) medical and pharmacy claims database, which contains data from >330 million patients, was the data source. Both subgroup and sensitivity analyses were conducted in addition to the core comparisons noted. In propensity score-adjusted analyses, receiving mRNA-1273 vs BNT162b2 as third dose was associated with 32% (relative risk [RR] 0.68; 95% confidence interval [CI] 0.51-0.89) , 29% (0.71; 0.57-0.86), and 23% (0.77; 0.62-0.93) lower risk of COVID-19 hospitalization after 90, 180, and 270 days, respectively. Corresponding reductions in medically-attended COVID-19 were 8% (0.92; 0.86-0.98), 6% (0.94; 0.90-0.98), and 2% (0.98; 0.94-1.02), respectively. Our findings suggest a third dose of mRNA-1273 is more effective than a third dose of BNT162b2 in preventing COVID-19 hospitalization and breakthrough medically-attended COVID-19 among IC adults in the US. ### Competing Interest Statement TS, LL, MG, JM, EB and NVV are employees of Moderna, Inc. and may hold stock/stock options in the company. ### Funding Statement This study was funded by Moderna, Inc. Employees of Moderna participated in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; or the decision to submit the manuscript for publication. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The research employed anonymized and deidentified healthcare claims data. IRB approval was not necessary. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Individual-level data reported in this study are not publicly shared. Upon request, and subject to review, Aetion, Inc. may provide the de-identified aggregate-level data that support the findings of this study. De-identified data (including participant data as applicable) may be shared upon approval of an analysis proposal and a signed data access agreement.