Researchers have developed a new all-in-one vaccine aimed at priming the body to respond to a range of different strains of coronaviruses, including the ones not yet known.

The researchers from Cambridge, MIT and CalTech published their findings recently in Nature Nanotechnology. Their vaccine was successfully tested on mice and will likely enter human clinical trials in early 2025.

Rory Hills, the first author of the study, told Health Policy Watch. “We are keen to implement the […] technology outlined in this study to develop broad vaccines against other pathogen groups including influenza. We would at least aim to protect against large groups of influenza viruses if not fully universal flu vaccine.”

Proactive vaccinology, creating vaccines for pathogens that do not exist as yet, is a promising branch of science allowing for a swift response to possible pandemics.

“Our focus is to create a vaccine that will protect us against the next coronavirus pandemic, and have it ready before the pandemic has even started,” said Hills.

Chains of antigens

The vaccine’s key part are receptor-binding-domains (RBDs), the part of the virus that enables it to enter host cells. For coronaviruses, they are placed at the tips of the characteristic ‘spikes’ resembling a crown, to which the viruses own their name.

The RBDs attach to structures on the cell membranes of the host organism, allowing the pathogen to enter and  infect the cell. The body’s immune reaction involves specialised T-cells developing receptors which capture the virus’s RBDs before it can attach to healthy cells.

It’s the T-cell’s ‘memory’ of the specific ‘shape’ of the RBDs that they have already encountered counts as immunity gained with vaccination.

The new catch-all coronavirus vaccine’s key component is a whole chain RBDs coming from different varieties of coronaviruses, connected with the so-called ‘spy-tag,’ a nano-superglue connecting the antigens to form a chain.

Each chain of four RBDs, or a quartet, is attached to a nanocage, a ball of proteins held together by incredibly strong interactions, which makes the construction base of the vaccine.

Broad immunity new to health systems

The vaccinated organism learns to create a response to the included antigens and even other ones that are similar. Mice in the trial developed an immune response to SARS-Cov-1, the virus that caused a multi-continent outbreak in the early 2000s, even though that virus was not included in the vaccine.

“We’ve created a vaccine that provides protection against a broad range of different coronaviruses – including ones we don’t even know about yet,” Hills highlighted.

As proactive vaccinology is only emerging, there are no medical procedures in place to accommodate for it and enable vaccination programs.

It is “new from a regulatory perspective and we will need to work with governments and regulators to develop approval processes and determine the best implementation,” predicted Hills for Health Policy Watch.

Hills sees several possibilities for using the catch-all vaccine., including “a strong vaccine against COVID-19 with the added benefit of protecting against additional coronaviruses”.

Alternatively, and, Hills said, “more likely,” is to “have this vaccine and a small library of other similarly broad vaccines against other pathogen groups developed, validated, and are ready to implement.”

“In the event that a coronavirus or other pathogen crosses over you could have pre-existing vaccine stocks ready and a clear plan to quickly scale up production if needed.”

Image Credits: Nature.