Antibody Response in Immunocompromised Patients After the Administration of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Vaccine BNT162b2 or mRNA-1273: A Randomized Controlled Trial

BACKGROUND

BNT162b2 by Pfizer-BioNTech and mRNA-1273 by Moderna are the most commonly used vaccines to prevent SARS-CoV-2 infections. Head-to-head comparison of the efficacy of these vaccines in immunocompromised patients is lacking.

METHODS

Parallel, two-arm (allocation 1:1), open-label, non-inferiority randomised clinical trial nested into the Swiss HIV Cohort Study and the Swiss Transplant Cohort Study. Patients living with HIV (PLWH) or solid organ transplant recipients (SOTR; i.e. lung and kidney) from these cohorts were randomised to mRNA-1273 or BNT162b2. The primary endpoint was antibody response to SARS-CoV-2 spike (S1) protein receptor binding domain (Elecsys Anti-SARS-CoV-2 immunoassay, Roche; cut-off ≥0.8 units/ml) 8 weeks after second vaccination. In addition, antibody response was measured with the Antibody CORonavirus Assay 2 (ABCORA 2).

RESULTS

430 patients were randomised and 412 were included in the intention-to-treat analysis (341 PLWH and 71 SOTR). The percentage of patients showing an immune response was 92.1% (95% confidence interval [CI] 88.4-95.8%; 186/202) for mRNA-1273 and 94.3% (95% CI 91.2-97.4; 198/210) for BNT162b2 (difference: 2.2%; 95% CI -7.1 to 2.7), fulfilling non-inferiority of mRNA-1273. With the ABCORA 2 test 89.1% had an immune response to mRNA-1273 (95% CI 84.8-93.4%; 180/202) and 89.5% to BNT162b2 (95% CI 85.4-93.7%; 188/210). Based on the Elecsys test, all PLWH had an antibody response (100.0%; 341/341), while for SOTR only 60.6% (95% CI 49.2-71.9%; 43/71) had titres above the cut-off.

CONCLUSIONS

In immunocompromised patients the antibody response of mRNA-1273 was non-inferior to BNT162b2. PLWH had in general an antibody response, while a high proportion of SOTR had no antibody response.