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Immune response of bivalent mRNA booster in adults who had received a primary series of an inactivated recombinant Newcastle disease virus vaccine expressing SARS-CoV-2 spike (NDV-HXP -S)

Year: 2025

Type: article

Abstract: An inactivated recombinant Newcastle disease virus vaccine expressing SARS-CoV-2 spike (NDV-HXP-S) is a novel inactivated COVID-19 vaccine platform. With possibilities for local manufacturing utilizing existing egg-based production technologies, NDV-HXP-S vaccines could be introduced if proven efficacious both as primary series or a booster dose. This study aims to assess the immune responses of the bivalent mRNA boost among participants primed with two NDV-HXP-S vaccine doses and had received heterologous COVID-19 vaccine booster doses. The prospective open-label study was conducted at Vaccine Trial Centre, Mahidol University, Thailand. Participants who had received either 3 µg, 3µg+CpG or 10µg of NDV-HXP-S doses and a first booster dose of either vector- or mRNA-based vaccines, at least 12 months earlier were enrolled. The bivalent mRNA COVID-19 (Spikevax bivalent Original/Omicron BA.4-5 25mcg/25mcg) was administered. Safety and immune responses in terms of anti-spike IgG (ELISA), Pseudovirus Neutralization Assay, and cellular immune response (QuantiFERON) were evaluated at D0, D28 and D90 after booster vaccination. From a total of 97 participants, 95 were included in per-protocol analysis; 37, 44 and 14 were previously primed with 3 µg, 3µg+CpG and 10µg of NDV-HXP-S, respectively. 41% and 52% participants received 4 and 5 doses of COVID-19 vaccine before bivalent booster. The bivalent mRNA booster dose was well tolerated. Anti-S IgG (Geometric mean fold rise (GMFR)) at D28 and D90 were 5.66/6.04/5.67 and 3.08/3.63/2.71 for 3 µg/ 3µg+CpG/ 10µg groups, respectively. GMFR of 50% Pseudo neutralization titer (PNT50) against Omicron (XBB.1.5) were 11.81/11.31/8.35 at D28 and 3.30/4.00/2.58 at DAY90. However, the magnitude of PNT50 against XBB.1.5 was much less than those of Wuhan. The IFN-Gamma (mIU/mL) of 3 µg/ 3µg+CpG/ 10µg were 1783.31/1773.25/1647.84 at baseline, 4280.06/5328.08/5194.80 at D28 and 2658.81/3755.21/2268.86 at Day90. The previous infection group had a higher GMFR of PNT50 (against XBB.1.5) than the no-infection group; 18.67/12.63/9.27 vs. 7.65/10.13/6.91 at D28 and 5.75/5.24/3.50 vs. 1.95/3.06/1.49 at D90. For IFN-Gamma, the GMT (mIU/mL) were at 2,079.12/5,046.49/4,088.73 vs. 4,721.11/2,741.91/3,645.65 at D28 and 2,234.36/4,437.50/2,726.84 vs. 4,206.49/2,314.98/3,712.65 at D90 in those with and without infection. Bivalent boosters could stimulate good immune response against the newer Omicron XBB 1.5 variant in all three groups regardless of the doses and with or without adjuvant. However, the magnitude declined significantly 90 days after. It appeared that the magnitude of T-cell responses especially with symptomatic infection appeared to be higher till D90 in the adjuvanted group (3+CpG). In the event of Omicron surges, the complexity of immune responses in hybrid immunity warrants further exploration. Good safety and immune responses were observed in the context of hybrid immunity and new VOCs, especially XBB.1.5., from bivalent mRNA booster over NDV-HXP-S primary series in all three groups.

Source: International Journal of Infectious Diseases

DOI: 10.1016/j.ijid.2024.107623