mRNA-1273 Noninferior to BNT162b2 After Third Vaccine Dose in Immunosuppressed

Results of a study published in Open Forum Infectious Diseases indicate noninferiority between mRNA-1273 and BNT162b2 vaccination among patients with varying levels of immunosuppression following receipt of a third COVID-19 vaccine dose.

In this extension of a randomized controlled noninferiority trial, researchers compared antibody responses among patients with varying levels of immunosuppression following receipt of a third COVID-19 vaccine dose. Patients were randomly assigned to receive either the mRNA -1273 or BNT162b2 vaccine, with blood samples collected up to 2 weeks prior or 8±2 weeks after receipt of the third vaccine dose. The primary outcome was the percentage of patients who experienced a positive antibody response (≥ 100 U/mL) to SARS-CoV-2 spike protein receptor-binding domain at 8 weeks.

A total of 312 (72.6%) patients from the previous study (N=430) participated in the extension study, of whom the median age was 54 (IQR, 44-60) years, 75% were men, and 90.7% had HIV infection. Of patients with HIV infection, most were virologically suppressed with CD4⁺ counts of more than 350 cells/µL. 

Positive antibody responses were noted among 95.3% (95% CI, 91.9%–98.7%) of patients in the mRNA-1273 group and 98.1% (95% CI, 95.9%–100.0%) of those in the BNT162b groups following receipt of the third vaccine dose, indicating noninferiority. In addition, seroconversion rates were similar between the groups (96.0% vs 99.0%, respectively).

Positive antibody responses were observed in 99.6% (95% CI, 98.9%-100.0%) of patients with HIV infection and 65.4% (95% CI, 47.1%-83.7%) of solid organ transplant (SOT) recipients following receipt of the third vaccine dose.

At 8 weeks, 14 (9.3%) patients in the mRNA-1273 group and 10 (6.4%) patients in the BNT162b2 group tested positive for COVID-19 infection.

This study was limited as several patients switched vaccine product following receipt of the second dose and many SOT recipients received a third COVID-19 vaccine dose prior to the release of national guidelines recommending a third dose for the entire population.

Based on these findings, “[The antibody response of Moderna mRNA-1273 compared to Pfizer-BioNTech BNT162b2 after third vaccination was noninferior in patients with different levels of immunosuppression,” the researchers noted. “Additional strategies (eg, new vaccines, monoclonal antibodies) need to be investigated for nonresponders such as SOT recipients,” the researchers concluded.

This article originally appeared on Infectious Disease Advisor