What question did this study set out to answer?

To evaluate the efficacy of a novel MERS-CoV nanoparticle vaccine in eliciting antibody responses and providing protection against viral challenge.

February 8, 2026Open Access

A stabilized MERS-CoV spike ferritin nanoparticle vaccine elicits robust and protective neutralizing antibody responses

Key Points

To evaluate the efficacy of a novel MERS-CoV nanoparticle vaccine in eliciting antibody responses and providing protection against viral challenge.
Designed and characterized a ferritin nanoparticle displaying stabilized MERS-CoV spike antigens.
Conducted immunizations in BALB/c mice and non-human primates (NHPs).
Evaluated neutralizing antibody titers and protective efficacy in various animal models.
The vaccine elicited robust neutralizing antibody titers in mice.
A single immunization in NHPs produced high geometric mean titers, boosted by a second dose.
Immunized NHP sera showed cross-reactivity against multiple coronavirus strains.
Vaccine provided dose-dependent protection in human DPP4 transgenic mice against lethal MERS-CoV challenge.
Full protection was observed in female alpacas after immunization.

Abstract

Abstract Middle East respiratory syndrome coronavirus (MERS-CoV) was identified as a human pathogen in 2012 and causes ongoing sporadic infections and outbreak clusters. Despite case fatality rates (CFRs) of over 30% and considerable pandemic potential, a safe and efficacious vaccine has not been developed. Here we report the design, characterization, and preclinical evaluation of MERS-CoV antigens. Our lead candidate comprises a stabilized spike displayed on a self-assembling ferritin nanoparticle that can be produced from a high-expressing, stable cell pool. This vaccine elicits robust MERS-CoV pseudovirus and authentic virus neutralizing antibody titers in BALB/c mice. Immunization of male non-human primates (NHPs) with one dose of Alhydrogel-adjuvanted vaccine elicited a > 10 3 geometric mean titer of pseudovirus neutralizing antibodies that was boosted with a second dose. Sera from these NHPs exhibited cross-reactivity against spike-pseudotyped lentiviruses from MERS-CoV clades A, B, and C as well as a distant pangolin merbecovirus. In human DPP4 transgenic mice, immunization provided dose-dependent protection against MERS-CoV lethal challenge, and in an established alpaca challenge model using female alpacas, immunization fully protected against MERS-CoV infection. This MERS-CoV nanoparticle vaccine is a promising candidate for clinical advancement to protect at-risk individuals and for future use in a potential outbreak setting.

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