One Vaccine To Fight Them All? Scientists Hold First Human Trial Of Universal Coronavirus Shot

No Needle, No Single Strain: Scientists Test a Vaccine Built to Battle a Broad Family of Coronaviruses

Three major coronavirus outbreaks in 20 years. Most scientists expect more. A team of researchers is now trying to get ahead of the next one with a single vaccine designed to work against a broad group of SARS-related coronaviruses at once, and delivered without a needle.

In a first-of-its-kind human trial published in the Journal of Infection, scientists tested a vaccine called pEVAC-PS, designed using computer modeling to target a broad group of SARS-related coronaviruses, not just the one behind COVID-19. The goal is ambitious: a single vaccine platform that could one day help protect against current and future coronavirus threats, whether from known variants of SARS-CoV-2 or from entirely new viruses lurking in animal populations. SARS in 2002, MERS in 2012, and COVID-19 beginning in 2019 have shown the pattern, and researchers argue it is too consistent to ignore.

Scientists Designed pEVAC-PS to Recognize Coronaviruses Before the Next Outbreak Hits

Thirty-nine healthy adults between 18 and 50 were enrolled, all previously vaccinated against COVID-19. Rather than a traditional needle and syringe, participants received injections through a pressure-based device that pushes the vaccine through the skin, an approach researchers say could make deployment far easier where medical needles are difficult to store or safely dispose of. Participants were split into four groups and received two doses each of pEVAC-PS at 0.2 mg, 0.4 mg, 0.8 mg, and 1.2 mg, with the second dose given 28 days after the first.

pEVAC-PS is a DNA vaccine, a type that delivers genetic instructions to cells, which then produce a protein that trains the immune system to recognize the virus. DNA vaccines are generally more heat-stable and easier to distribute than mRNA vaccines because they do not require ultra-cold storage. A trade-off exists: DNA must travel into the cell’s nucleus to be read, making it harder for the body to mount as strong a response. pEVAC-PS was designed to focus the immune system’s attention on parts of the coronavirus that stay largely the same across many different variants and related viruses, with the idea that recognizing those stable, shared structures could help fight off a wide range of threats.

Running from December 2021 through September 2023, the trial landed squarely in the Omicron wave era, which created real complications. Because participants were enrolled across different periods, each group came in with different COVID-19 exposure histories. Some contracted COVID-19 between doses and had to be removed from the immune response analysis, and others were excluded after screening revealed infections they may not have known they had.

Vaccine Proved Safe Across All Doses, but Immune Response Remained Modest

On safety, the results were encouraging. No serious adverse reactions occurred, and the vaccine was well tolerated across all four dose levels with no clear pattern of worse side effects at higher doses. Most reported reactions were mild to moderate, soreness at the injection site or flu-like symptoms, and tended to be fewer after the second dose than the first. Seven moderate-to-severe reactions in one participant from the lowest-dose group were traced to a COVID-19 infection that coincided with the vaccination window, not the vaccine itself.

Antibody levels were modest across the board and did not clearly rise in proportion to the dose. In the highest-dose group, a statistically meaningful increase in antibody binding to the vaccine’s target protein appeared by week six, but the magnitude fell short of the strong, dose-dependent rise researchers would ideally want to see. Neutralizing activity was measured only in the two higher-dose groups, with some increases found against Omicron BA.1 in one group and the Delta variant in another, while activity against the original Wuhan strain and the original SARS virus remained largely unchanged.

Immune System Targeted the Right Viral Regions, Even if the Response Wasn’t Strong Enough

Among the more intriguing findings was a detailed analysis of which parts of the coronavirus the immune responses were targeting. A subset of participants showed antibody activity in regions of the virus critical for infection, including a region recognized by S309, a broadly neutralizing monoclonal antibody studied in prior SARS research. Though the researchers note that binding to this region may not directly translate into broad functional neutralization, the vaccine appears to be directing the immune system toward the right parts of the virus.

Interpreting this trial is tricky, and the researchers are candid about that. Study conditions were complicated by an active pandemic with constantly shifting variants, meaning participants arrived with very different levels of pre-existing immunity. Those differences make it hard to draw firm conclusions about the vaccine’s boosting effect. Adding to that, the trial had no standard vaccine comparison group, immune response tests were developed in-house rather than validated against outside benchmarks, and the groups were too small to draw confident dose-response conclusions.

Despite all that, the researchers say the trial accomplished its primary goal: showing that the vaccine is safe, that needle-free delivery is feasible, and that the immune system does respond to the shared coronavirus structures the vaccine was designed to target. COVID-19 variants keep emerging and outpacing updated vaccines, and bats carry a large reservoir of related coronaviruses that scientists believe could one day infect humans. Whether pEVAC-PS can be made to work powerfully enough to matter against those threats is the question researchers will need to answer next.

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Disclaimer: This article is based on a published phase I clinical trial and is intended for informational purposes only. Phase I trials are designed primarily to assess safety, not to establish that a vaccine works. The findings described here are preliminary and do not indicate that pEVAC-PS is approved, proven effective, or ready for widespread use. Readers should consult qualified health professionals for guidance on vaccines and personal health decisions.

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