Data availability
The data that support the findings of this study are not openly available due to reasons of commercial sensitivity but are available from the corresponding author upon request. Data are located in controlled-access LabArchives data storage at the University of Melbourne.
References
-
Wang, P. et al. Increased resistance of SARS-CoV-2 Variants B.1.351 and B.1.1.7 to antibody neutralization. https://doi.org/10.1101/2021.1101.1125.428137 (2021).
-
Davies, N. G. et al. Increased mortality in community-tested cases of SARS-CoV-2 lineage B.1.1.7. Nature 593, 270–274 (2021).
-
Qu, P. et al. Evasion of neutralizing antibody responses by the SARS-CoV-2 BA.2.75 variant. Cell Host Microbe 30, 1518–1526 e1514 (2022).
-
Takashita, E. et al. In vitro efficacy of antiviral agents against omicron subvariant BA.4.6. N. Engl. J. Med. 387, 2094–2097 (2022).
-
Arora, P. et al. Omicron sublineage BQ.1.1 resistance to monoclonal antibodies. Lancet Infect. Dis. 23, 22–23 (2023).
-
Voysey, M. et al. Single-dose administration and the influence of the timing of the booster dose on immunogenicity and efficacy of ChAdOx1 nCoV-19 (AZD1222) vaccine: a pooled analysis of four randomised trials. Lancet. https://doi.org/10.1016/S0140-6736(21)00432-3 (2021).
-
Polack, F. P. et al. Safety and efficacy of the BNT162b2 mRNA Covid-19 vaccine. N. Engl. J. Med. 383, 2603–2615 (2020).
-
Uraki, R. et al. Humoral immune evasion of the omicron subvariants BQ.1.1 and XBB. Lancet Infect. Dis. 23, 30–32 (2023).
-
Kurhade, C. et al. Low neutralization of SARS-CoV-2 Omicron BA.2.75.2, BQ.1.1, and XBB.1 by parental mRNA vaccine or a BA.5-bivalent booster. Nat. Med. https://doi.org/10.1038/s41591-022-02162-x (2022).
-
Planas, D. et al. Distinct evolution of SARS-CoV-2 Omicron XBB and BA.2.86/JN.1lineages combining increased fitness and antibody evasion. Nat. Commun. 15, 2254 (2024).
-
Yang, S. et al. Fast evolution of SARS-CoV-2 BA.2.86 to JN.1 under heavy immune pressure. Lancet Infect. Dis. 24, e70–e72 (2024).
-
Zou, J. et al. Neutralization of BA.4-BA.5, BA.4.6, BA.2.75.2, BQ.1.1, and XBB.1with Bivalent Vaccine. N Engl. J. Med. 388, 854–857 (2023).
-
Chalkias, S. et al. Three-month antibody persistence of a bivalent omicron-containing booster vaccine against COVID-19. Res. Sq. https://doi.org/10.21203/rs.3.rs-2239682/v1 (2022).
-
Wang, Q. et al. Antibody response to omicron BA.4-BA.5 bivalent booster. N. Engl. J. Med. https://doi.org/10.1056/NEJMc2213907 (2023).
-
Collier, A. Y. et al. Immunogenicity of BA.5 Bivalent mRNA vaccine boosters. N. Engl. J. Med. https://doi.org/10.1056/NEJMc2213948 (2023).
-
Fabiani, M. et al. Protection against severe COVID-19 after second booster dose of adapted bivalent (original/Omicron BA.4-5) mRNA vaccine in persons >/=60 years, by time since infection, Italy, 12 September to 11 December 2022. Euro Surveill. 28. https://doi.org/10.2807/1560-7917.ES.2023.28.8.2300105 (2023).
-
Liu, J. et al. Virological and antigenic characteristics of SARS-CoV-2 variants LF.7.2.1, NP.1, and LP.8.1. Lancet Infect. Dis. 25, e128–e130 (2025).
-
Guo, C. et al. Antigenic and virological characteristics of SARS-CoV-2 variants BA.3.2, XFG, and NB.1.8.1. Lancet Infect. Dis. 25, e374–e377 (2025).
-
Addo, I. Y., Dadzie, F. A., Okeke, S. R., Boadi, C. & Boadu, E. F. Duration of immunity following full vaccination against SARS-CoV-2: a systematic review. Arch. Public Health 80, 200 (2022).
-
Tu, W. et al. SARS-CoV-2 infection, hospitalization, and death in vaccinated and infected individuals by age groups in Indiana, 2021‒2022. Am. J. Public Health 113, 96–104 (2023).
-
Mesle, M. M. I. et al. Estimated number of lives directly saved by COVID-19 vaccination programmes in the WHO European Region from December, 2020, to March, 2023: a retrospective surveillance study. Lancet Respir. Med. 12, 714–727 (2024).
-
Link-Gelles, R. et al. Interim estimates of 2024-2025 COVID-19 vaccine effectiveness among adults aged >/=18 Years—VISION and IVY networks, September 2024–January 2025. Morb. Mortal. Wkly Rep. 74, 73–82 (2025).
-
Suryawanshi, R. K. et al. Limited cross-variant immunity from SARS-CoV-2 Omicron without vaccination. Nature 607, 351–355 (2022).
-
Collett, S. et al. Development of virus-like particles with inbuilt immunostimulatory properties as vaccine candidates. Front. Microbiol. 14, 1065609 (2023).
-
Sekine, T. et al. Robust T cell immunity in convalescent individuals with asymptomatic or mild COVID-19. Cell 183, 158–168 e114 (2020).
-
Grifoni, A. et al. Targets of T cell responses to SARS-CoV-2 coronavirus in humans with COVID-19 disease and unexposed individuals. Cell 181, 1489–1501 e1415 (2020).
-
Sette, A. & Crotty, S. Adaptive immunity to SARS-CoV-2 and COVID-19. Cell 184, 861–880 (2021).
-
Tarke, A. et al. SARS-CoV-2 vaccination induces immunological T cell memory able to cross-recognize variants from Alpha to Omicron. Cell 185, 847–859 e811 (2022).
-
Augusto, D. G. et al. A common allele of HLA is associated with asymptomatic SARS-CoV-2 infection. Nature 620, 128–136 (2023).
-
Chalkias, S. et al. A bivalent omicron-containing booster vaccine against Covid-19. N. Engl. J. Med. 387, 1279–1291 (2022).
-
Li, Q. et al. Cross-reactivity of eight SARS-CoV-2 variants rationally predicts immunogenicity clustering in sarbecoviruses. Signal Transduct. Target. Ther. 7, 256 (2022).
-
Moyo-Gwete, T. et al. Shared N417-dependent epitope on the SARS-CoV-2 Omicron, Beta, and Delta Plus variants. J. Virol. 96, e0055822 (2022).
-
Launay, O. et al. Immunogenicity and safety of beta-adjuvanted recombinant booster vaccine. N. Engl. J. Med 387, 374–376 (2022).
-
Choi, A. et al. Safety and immunogenicity of SARS-CoV-2 variant mRNA vaccine boosters inhealthy adults: an interim analysis. Nat. Med. 27, 2025–2531 (2021).
-
Klinakis, A., Cournia, Z. & Rampias, T. N-terminal domain mutations of the spike protein are structurally implicated in epitope recognition in emerging SARS-CoV-2 strains. Comput. Struct. Biotechnol. J. 19, 5556–5567 (2021).
-
Dacon, C. et al. Broadly neutralizing antibodies target the coronavirus fusion peptide. Science 377, 728–735 (2022).
-
Edeling, M. A. et al. Development of methods to produce SARS-CoV-2 virus-like particles at scale. Biotechnol. Bioeng. https://doi.org/10.1002/bit.28937 (2025).
-
Hsieh, C. L. et al. Structure-based design of prefusion-stabilized SARS-CoV-2 spikes. Science 369, 1501–1505 (2020).
-
Carrera Montoya, J. et al. Human nasal epithelium organoids for assessing neutralizing antibodies to a protective SARS-CoV-2 virus-like particle vaccine. Organoids 3, 0–13 (2024).
-
Melbourne, T. U. o. Stabilised virus-like particles and uses there of. Australian Provisional Patent Application No. 2024903881 (2024).
-
Townsend, J. A. et al. Differences in oligomerization of the SARS-CoV-2 envelope protein, poliovirus VP4, and HIV Vpu. Biochemistry 63, 241–250 (2024).
-
Mandala, V. S. et al. Structure and drug binding of the SARS-CoV-2 envelope protein transmembrane domain in lipid bilayers. Nat. Struct. Mol. Biol. 27, 1202–1208 (2020).
-
Zhang, R. et al. Dimeric transmembrane structure of the SARS-CoV-2 E protein. Commun. Biol. 6, 1109 (2023).
-
Tan, C. W. et al. A SARS-CoV-2 surrogate virus neutralization test based on antibody-mediated blockage of ACE2-spike protein-protein interaction. Nat. Biotechnol. 38, 1073–1078 (2020).
-
Tan, C. W. et al. Pan-sarbecovirus neutralizing antibodies in BNT162b2-immunized SARS-CoV-1 survivors. N. Engl. J. Med. 385, 1401–1406 (2021).
-
Zhuang, Z. et al. Mapping and role of T cell response in SARS-CoV-2-infected mice. J. Exp. Med. 218. https://doi.org/10.1084/jem.20202187 (2021).
-
Hassert, M. et al. mRNA-induced expression of human angiotensin-converting enzyme 2 in mice for the study of the adaptive immune response to severe acute respiratory syndrome coronavirus 2. PLoS Pathog. 16, e1009163 (2020).
-
van Bergen, J. et al. Multiantigen pan-sarbecovirus DNA vaccines generate protective T cell immune responses. JCI Insight 8. https://doi.org/10.1172/jci.insight.172488 (2023).
-
Kingstad-Bakke, B. et al. Vaccine-induced systemic and mucosal T cell immunity to SARS-CoV-2 viral variants. Proc. Natl. Acad. Sci. USA 119, e2118312119 (2022).
-
Tarres-Freixas, F. et al. Heterogeneous infectivity and pathogenesis of SARS-CoV-2 variants Beta, Delta and Omicron in transgenic K18-hACE2 and wildtype mice. Front. Microbiol. 13, 840757 (2022).
-
Gary, E. N. et al. A novel mouse AAV6 hACE2 transduction model of wild-type SARS-CoV-2 infection studied using synDNA immunogens. iScience 24, 102699 (2021).
-
Rathnasinghe, R. et al. Comparison of transgenic and adenovirus hACE2 mouse models for SARS-CoV-2 infection. Emerg. Microbes Infect. 9, 2433–2445 (2020).
-
Tailor, N. et al. Generation and characterization of a SARS-CoV-2-susceptible mouse model using adeno-associated virus (AAV6.2FF)-mediated respiratory delivery of the human ACE2 gene. Viruses 15. https://doi.org/10.3390/v15010085 (2022).
-
Glazkova, D. V. et al. Generation of SARS-CoV-2 mouse model by transient expression of the human ACE2 gene mediated by intranasal administration of AAV-hACE2. Mol. Biol. 56, 705–712 (2022).
-
Tran, B. M. et al. Air-liquid-interface differentiated human nose epithelium: a robust primary tissue culture model of SARS-CoV-2 infection. Int. J. Mol. Sci. 23, https://doi.org/10.3390/ijms23020835 (2022).
-
Chen, Y. et al. Broadly neutralizing antibodies to SARS-CoV-2 and other human coronaviruses. Nat. Rev. Immunol. 23, 189–199 (2023).
-
Wu, W. L. et al. Monoclonal antibody targeting the conserved region of the SARS-CoV-2 spike protein to overcome viral variants. JCI Insight 7. https://doi.org/10.1172/jci.insight.157597 (2022).
-
Wang, Z. et al. Analysis of memory B cells identifies conserved neutralizing epitopes on the N-terminal domain of variant SARS-CoV-2 spike proteins. Immunity 55, 998–1012 e1018 (2022).
-
Ng, K. W. et al. SARS-CoV-2 S2-targeted vaccination elicits broadly neutralizing antibodies. Sci. Transl. Med. 14, eabn3715 (2022).
-
Pinto, D. et al. Broad betacoronavirus neutralization by a stem helix-specific human antibody. Science 373, 1109–1116 (2021).
-
Dacon, C. et al. Rare, convergent antibodies targeting the stem helix broadly neutralize diverse betacoronaviruses. Cell Host Microbe 31, 97–111 e112 (2023).
-
Richardson, S. I. et al. SARS-CoV-2 Beta and Delta variants trigger FC effector function with increased cross-reactivity. Cell Rep. Med. 3, 100510 (2022).
-
Madhi, S. A. et al. Efficacy of the ChAdOx1 nCoV-19 Covid-19 Vaccine against the B.1.351 Variant. N Engl J Med 384, 1885–98 (2021).
-
Kustin, T. et al. Evidence for increased breakthrough rates of SARS-CoV-2 variants ofconcern in BNT162b2-mRNA-vaccinated individuals. Nat. Med. 27, 1379–1384 (2021).
-
Li, Q. et al. The impact of mutations in SARS-CoV-2 spike on viral infectivity and antigenicity. Cell. https://doi.org/10.1016/j.cell.2020.07.012 (2020).
-
Nguyen, T. H. O., et al. CD8+ T cells specific for an immunodominant SARS-CoV-2 nucleocapsid epitope display high naïve precursor frequency and T cell receptor promiscuity. Immunity. https://doi.org/10.1016/j.immuni.2021.04.009 (2021).
-
Wagner, K. I. et al. Recruitment of highly cytotoxic CD8(+) T cell receptors in mild SARS-CoV-2 infection. Cell Rep. 38, 110214 (2022).
-
Bertoletti, A., Le Bert, N. & Tan, A. T. SARS-CoV-2-specific T cells in the changing landscape of the COVID-19 pandemic. Immunity 55, 1764–1778 (2022).
-
Guo, L. et al. SARS-CoV-2-specific antibody and T-cell responses 1 year after infection in people recovered from COVID-19: a longitudinal cohort study. Lancet Microbe 3, e348–e356 (2022).
-
Rydyznski Moderbacher, C. et al. Antigen-specific adaptive immunity to SARS-CoV-2 in acute COVID-19 and associations with age and disease severity. Cell 183, 996–1012 e1019 (2020).
-
Schulz, A. R. et al. SARS-CoV-2 specific plasma cells acquire long-lived phenotypes in human bone marrow. EBioMedicine 95, 104735 (2023).
-
Nguyen, D. C. et al. COVID-19 and plasma cells: is there long-lived protection? Immunol. Rev. 309, 40–63 (2022).
-
Giannotta, G. & Giannotta, N. mRNA COVID-19 vaccines and long-lived plasma cells: a complicated relationship. Vaccines 9. https://doi.org/10.3390/vaccines9121503 (2021).
-
Halliley, J. L. et al. Long-lived plasma cells are contained within the CD19(-)CD38(hi)CD138(+) subset in human bone marrow. Immunity 43, 132–145 (2015).
-
Turner, J. S. et al. SARS-CoV-2 mRNA vaccines induce persistent human germinal centre responses. Nature 596, 109–113 (2021).
-
Kato, Y. et al. Multifaceted effects of antigen valency on B cell response composition and differentiation in vivo. Immunity 53, 548–563 e548 (2020).
-
Bhattacharya, D. Instructing durable humoral immunity for COVID-19 and other vaccinable diseases. Immunity 55, 945–964 (2022).
-
Cyster, J. G. & Allen, C. D. C. B Cell responses: cell interaction dynamics and decisions. Cell 177, 524–540 (2019).
-
Bennett, N. R., Zwick, D. B., Courtney, A. H. & Kiessling, L. L. Multivalent antigens for promoting B and T cell activation. ACS Chem. Biol. 10, 1817–1824 (2015).
-
Brooks, J. F. et al. Molecular basis for potent B cell responses to antigen displayed on particles of viral size. Nat. Immunol. 24, 1762–1777 (2023).
-
Ferapontov, A. et al. Antigen footprint governs activation of the B cell receptor. Nat. Commun. 14, 976 (2023).
-
Yao, H. et al. Molecular architecture of the SARS-CoV-2 virus. Cell 183, 730–738 e713 (2020).
-
Christiansen, D. et al. Pre-clinical evaluation of a quadrivalent HCV VLP vaccine in pigs following microneedle delivery. Sci. Rep. 9, 9251 (2019).
-
Cai, J. P. et al. Intranasal boosting with spike Fc-RBD of Wild-Type SARS-CoV-2 induces neutralizing antibodies against omicron subvariants and reduces viral load in the nasal turbinate of mice. Viruses 15. https://doi.org/10.3390/v15030687 (2023).
-
Tabynov, K. et al. An intranasal vaccine comprising SARS-CoV-2 spike receptor-binding domain protein entrapped in mannose-conjugated chitosan nanoparticle provides protection in hamsters. Sci. Rep. 13, 12115 (2023).
-
Xing, M. et al. An intranasal combination vaccine induces systemic and mucosal immunity against COVID-19 and influenza. NPJ Vaccines 9, 64 (2024).
-
Earnest-Silveira, L. et al. Characterization of a hepatitis C virus-like particle vaccine produced in a human hepatocyte-derived cell line. J. Gen. Virol. 97, 1865–1876 (2016).
-
Deliyannis, G. et al. Broad immunity to SARS-CoV-2 variants of concern mediated by a SARS-CoV-2 receptor-binding domain protein vaccine. EBioMedicine 92, 104574 (2023).
-
Hierholzer, J. C. & Killington, R. A. Virus isolation and quantitation. Virology Methods Manual, 25–46 (Elsevier, 1996).
Acknowledgements
This work was supported by grants from the National Health and Medical Research Council (NHMRC) Medical Research Future Fund (MRFF) (APP2013957), Avalia Immunotherapies Limited, Wellington, New Zealand, Vaccine Alliance Aotearoa New Zealand, Wellington, New Zealand; JT and DG acknowledge support from the Jack Ma Foundation for parts of the SARS-CoV-2 VLP work in this manuscript. SG is supported by an NHMRC Senior Research Fellowship (1159272). DIG was supported by an NHMRC Senior Research Fellowship (1117766) and subsequently by an NHMRC Investigator Grant (2008913). The salary for EV was supported by an NHMRC Ideas grant awarded to EV and JT (APP1181580). For W.R.H. by NHMRC 1154457, and for L.E.H. by NHMRC 2012701. LFW and CWT at Duke-NUS, supported by grants from Singapore National Medical Research Council (STPRG-FY19-001, COVID19RF-003 and OFLCG19-May-0034). D.F.J.P is supported by the MRFF mRNA Clinical Trial Enabling Infrastructure Grant MRFCTI000025 through the Department of Industry, Science Energy and Resources (DISER) “RNA Powered Antiviral Antibodies”. The authors would like to thank Rebecca Plavcak and Charley Mackenzie-Kludas for technical support for during the murine studies conducted at the Doherty Institute. We also thank Yaseelan Palarasah, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark, for providing anti-RBD monoclonal antibody, clone 20-14-5, for immunoprecipitation studies.
Ethics declarations
Competing interests
Two patents (PCT/AU2022/050844 and PCT/AU2022/050843) covering the SARS-CoV-2 VLP vaccines and the underlying technology described in this study have been submitted through The University of Melbourne, with D.I.G. and J.T. as co-inventors. C.W.T. and L.-F.W. are co-inventors of a patent on the surrogate virus neutralization test (sVNT) platform. S.R. is an employee of CSL Seqirus. The authors declare no competing interests.
Additional information
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary information
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
About this article
Cite this article
Earnest, L., Ruiz, D.F., Edeling, M.A. et al. Preclinical development of a cross-protective β-SARS-CoV-2 virus-like particle vaccine adjuvanted with MF59. npj Vaccines (2026). https://doi.org/10.1038/s41541-025-01355-y
-
Received:
-
Accepted:
-
Published:
-
DOI: https://doi.org/10.1038/s41541-025-01355-y
