Phumratanaprapin W.Luvira V.Lawpoolsri S.Cowan J.Muangnoicharoen S.Kamolratanakul S.Sabmee Y.Narakorn P.Surichan S.Mercer L.D.Raghunandan R.Polyak C.S.Wirachwong P.Flores J.Innis B.L.Pitisuttithum P.Mahidol University2026-01-012026-01-012025-12-01Npj Vaccines Vol.10 No.1 (2025)https://repository.li.mahidol.ac.th/handle/123456789/113701To promote self-reliance in vaccine production, a chimeric Newcastle Disease Virus (NDV) based vaccine (NDV-HXP-S) was developed in Bangkok, Thailand, with the support of PATH. The interim results of phase 1 on initial safety and immune responses of five formulations: 1 µg, 3 µg, 10 µg, 1 µg+ CpG, and 3 µg+CpG adjuvant were reported. The 3 µg and 3 µg+CpG formulations were selected to advance into phase 2. The full one-year follow-up of safety and immune responses of the NDV-HXP-S vaccine from a pooled phase 1/2 randomized, double-blind, placebo-controlled trial in vaccine naïve individuals with no prior SARS-CoV-2 infection was reported here. The two-dose NDV-HPX-S primary series was safe and elicited a strong immune response over one year, especially in the 3 µg+CpG and 10 µg groups. The 3 µg+CpG group had a significantly higher geometric mean fold rise (GMFR) than the 3 µg group (57.1 vs 40.0, p = 0.028) 14 days after the second dose.Pharmacology, Toxicology and PharmaceuticsMedicineImmunology and MicrobiologyArticleSCOPUS10.1038/s41541-025-01321-82-s2.0-10502539922020590105