A series of recently published preclinical study results show that the Spike Ferritin Nanoparticle (SpFN) COVID-19 vaccine developed by researchers at the Walter Reed Army Institute of Research in Silver Spring, Maryland not only elicits a potent immune response but may also provide broad protection against SARS-CoV-2 variants of concern as well as other coronaviruses.

Scientists in WRAIR's Emerging Infectious Diseases Branch (EIDB) developed the SpFN nanoparticle vaccine, based on a ferritin platform, as part of a forward-thinking "pan-SARS" strategy that aims to address the current pandemic and acts as a first line of defense against variants of concern and similar viruses that could emerge in the future.

"The accelerating emergence of human coronaviruses throughout the past two decades and the rise of SARS-CoV-2 variants, including most recently Omicron, underscore the continued need for next-generation preemptive vaccines that confer broad protection against coronavirus diseases," said Dr. Kayvon Modjarrad, director of the Emerging Infectious Diseases Branch at WRAIR, co-inventor of the vaccine and the Army lead for SpFN. "Our strategy has been to develop a 'pan-coronavirus' vaccine technology that could potentially offer safe, effective and durable protection against multiple coronavirus strains and species."

Pre-clinical studies published today in Science Translational Medicine indicate that the SpFN vaccine protects non-human primates from disease caused by the original strain of SARS-CoV-2 and induces highly-potent and broadly-neutralizing antibody responses against major SARS-CoV-2 variants of concern including the SARS-CoV-1 virus that emerged in 2002.

SpFN entered Phase 1 human trials in April 2021. Early analyses, expected to conclude this month, will provide insights into whether SpFN's potency and breadth, as demonstrated in preclinical trials, will carry over into humans. The data will also allow researchers to compare SpFN's immune profile to that of other COVID-19 vaccines already authorized for emergency use.

"This vaccine stands out in the COVID-19 vaccine landscape," Modjarrad said. "The repetitive and ordered display of the coronavirus spike protein on a multi-faced nanoparticle may stimulate immunity in such a way as to translate into significantly broader protection."

WRAIR developed a secondary candidate vaccine, a SARS-CoV-2 Spike Receptor-Binding Domain Ferritin Nanoparticle (RFN) vaccine, which targets a smaller part of the coronavirus Spike protein than the SpFN vaccine. Results from a study, published recently in the Proceedings of the National Academy of Sciences, show that this vaccine potentially offers similar protection against an array of SARS-CoV-2 variants and SARS-CoV-1.

"The RFN vaccine candidate is more compact and has some natural advantages as we try to increase the immune response against multiple coronaviruses using a single vaccine platform, so it is still under consideration as part of our pan-coronavirus vaccine development pipeline," said Dr. Gordon Joyce, WRAIR structural biologist and vaccine co-inventor.

"The threat from COVID-19 continues as it evolves, and eventually there will be other emerging disease threats," said Dr. Nelson Michael, director of the Center for Infectious Diseases Research at WRAIR. "Our investment in developing a next generation vaccine is an important step towards getting ahead of COVID-19 and future disease threats."