Immunogenicity of Extended mRNA SARS-CoV-2 Vaccine Dosing Intervals

Abstract

This study investigates the immunogenicity of extended mRNA vaccine dosing intervals.

Figure 1.. Comparison of Serological Outcomes in Paramedics Who Received Short (≤28 Days) vs Medium (42-49 Days) mRNA Vaccine Dosing Intervals

The solid lines indicate the geometric mean. P values were derived from the Wilcoxon matched-pair signed rank test. A, Reciprocal of live viral Wuhan strain neutralization titers, expressed as highest serum dilution able to block viral cytotoxicity (geometric mean, 54.6 [geometric SD {GSD}, 3.0] for the short group vs 230.8 [GSD, 2.0] for the medium group). The dashed line indicates the lower limit of detection with values below set at 1:4. B, The antibody IgG concentration for the multiplex spike was 87 292 arbitrary units (AU)/mL (SD, 5.4 AU/mL) for the short group vs 163 167 AU/mL (SD, 2.2 AU/mL) for the medium group and for the receptor-binding domain (RBD) was 51 753 AU/mL (SD, 5.3 AU/mL) for the short group vs 128 987 U/mL (SD, 2.3 U/mL) for the medium group. C, Inhibition of angiotensin-converting enzyme 2 (ACE-2) binding to the SARS-CoV-2 receptor-binding domain for the Wuhan strain was 24.0 U/mL (SD, 1.9 U/mL) for the short group vs 31.9 U/mL (SD, 2.4 U/mL) for the medium group; for the Delta variant it was 8.64 U/mL (SD, 2.1 U/mL) for the short group vs 22.3 U/mL (SD, 2.0 U/mL) for the medium group.

Figure 2.. Comparison of Serological Outcomes in Paramedics Who Received Short (≤36 Days) vs Long (100-120 Days) mRNA Vaccine Dosing Intervals

The solid lines indicate the geometric mean. P values were derived from the Wilcoxon matched-pair signed rank test. A, Reciprocal of live viral Wuhan strain neutralization titers, expressed as highest serum dilution able to block viral cytotoxicity (geometric mean, 41.8 [geometric SD {GSD}, 2.8] for the short group vs geometric mean, 302.3 [GSD, 2.4] for the long group). The dashed line indicates the lower limit of detection with values below set at 1:4. B, The antibody IgG concentration for the multiplex spike was 45 155 arbitrary units (AU)/mL (SD, 2.3 AU/mL) for the short group vs 129 299 AU/mL (SD, 2.8 AU/mL) for the long group. The receptor-binding domain (RBD) was 22 071 AU/L (SD, 2.4 AU/L) vs 66 022 AU/L (SD, 2.9 AU/L). C, Inhibition of angiotensin-converting enzyme 2 (ACE-2) binding to SARS-CoV-2 receptor binding domain for the Wuhan strain was 7.9 U/mL (SD,1.6 U/mL) vs 26.8 U/mL (SD, 2.9 U/mL) and for the Delta variant, 2.7 U/mL (SD, 1.5 U/mL) vs 8.7 U/mL (Sd, 2.4 U/mL).