Scientists at the Walter Reed Army Institute of Research are leading a massive project aimed at developing a universal coronavirus vaccine that can provide protection against all SARS-CoV-2 variants. A handful of newly published studies are reporting successful preclinical results and Phase 2 human trials are set to kick off very soon.
As scientists around the world received the first genomic sequences of SARS-CoV-2 in early 2020 many began to work on developing an all-important vaccine. A team from the Walter Reed Army Institute of Research (WRAIR) decided to tackle the problem from a different angle. Instead of racing to produce a specific, targeted SARS-CoV-2 vaccine the researchers chose to play a longer game and investigate a more broadly protective vaccine that could produce immune responses against all kinds of coronaviruses, including any specific variants that may arise.
“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,” explains Kayvon Modjarrad, from WRAIR’s Emerging Infectious Diseases Branch. “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.”
Now, two years into this global pandemic, the research is bearing fruit as a number of recently published studies outline an innovative nanoparticle vaccine. The vaccine is called SpFN, or the spike ferritin nanoparticle vaccine.
Instead of focusing on a single permutation of the SARS-CoV-2 spike protein, as most first-wave COVID-19 vaccines have, this technology harnesses the unique structure of ferritin proteins to present the body with a broad array of different coronavirus antigens.
Ferritin is a naturally occurring protein best known as an iron-carrying particle in human bodies. Its unique structure has been said to resemble a soccer ball in that it has 24 different faces. Before the pandemic researchers had been investigating ferritin nanoparticles as a technology for a universal influenza vaccine because a different viral antigen can be attached to each of those 24 faces.
In the context of a coronavirus vaccine, scientists can attach a different spike protein to each of the 24 faces of a ferritin nanoparticle. This means a single nanoparticle could hold spikes from not only a variety of SARS-CoV-2 variants, but a variety of other common coronaviruses.
“This vaccine stands out in the COVID-19 vaccine landscape,” explains Modjarrad. “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.”
Over the last few months WFAIR researchers have published a number of preclinical studies testing its SpFN vaccine in animals. All studies demonstrated the novel vaccine produced robust immune responses against several SARS-CoV-2 variants.
But perhaps the most promising preclinical study was published in mid-December in Science Translational Medicine. It reported extraordinarily broad neutralizing antibody responses in nonhuman primates against a variety of SARS-CoV-2 variants as well as effective immune responses against the original SARS virus from 2002.
In April 2021 the research team started a Phase 1 human clinical trial testing the safety of the vaccine in a cohort of healthy adults. Results from the Phase 1 trial are yet to be formally announced but Modjarrad did reveal last month that the trial was successful, saying in an interview with Defense One, “so far everything has been moving along exactly as we had hoped.”
Alongside an expansive six-month trial testing both a two- and three-dose protocol, a reason the Phase 1 trial has taken so long is the researchers wanted to track down participants who had either not yet been vaccinated or not been infected with SARS-CoV-2. As you can imagine, finding a willing cohort to fulfill those criteria in 2021 would have been challenging.
Modjarrad has indicated the research team will be testing the effect of vaccine-induced antibodies against all known circulating SARS-CoV-2 variants, including Omicron. A full announcement with those Phase 1 trial results is expected soon.
The researchers are also working on a trial looking at the safety of the vaccine in those previously vaccinated with a current COVID-19 vaccine, and in those who have previously been infected with the virus.
“We need to evaluate it in the real-world setting and try to understand how does the vaccine perform in much larger numbers of individuals who have already been vaccinated with something else initially … or already been sick,” Modjarrad said to Defense One.
The research still has a long road ahead, with thorough Phase 2 and 3 human trials needed to establish safety and efficacy. But a single pan-coronavirus vaccine that can tackle emerging variants is a pretty promising prospect, and if this one is successful it could be profoundly valuable in both the ongoing fight against SARS-CoV-2 variants and any other novel coronaviruses that could emerge in the future.
Source: US Army
