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All participants had already received prior COVID vaccinations, making it impossible to determine whether observed immunity came from the experimental shot, prior vaccines, or natural infection.

Researchers behind an experimental AI-designed “pan-Sarbecovirus” COVID vaccine recorded 148 separate adverse events among just 39 vaccinated participants during a first-in-human clinical trial published last month in the Journal of Infection.

The vaccine, known as pEVAC-PS, was developed using “Digitally Immune Optimised Synthetic Vaccine” (DIOSynVax) technology and was computationally engineered to target not only SARS-CoV-2, but a broad family of purportedly related bat coronaviruses.

The vaccine was delivered through a needle-free intradermal injection system using the PharmaJet Tropis device.

The mainstream is celebrating the drug as a “world-first.”

However, according to the paper, researchers documented:

• 121 unsolicited adverse events,
• 15 adverse events of special interest (AESIs),
• and 12 clinically significant laboratory adverse events

across only 39 vaccinated participants.

That’s roughly 3.8 total recorded adverse-event entries per vaccinated participant in the small phase I trial.

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The study further states that 23 of the unsolicited adverse events were considered “possibly,” “probably,” or “definitely” related to the vaccine.

The paper nevertheless repeatedly describes the vaccine as “well tolerated.”

The paper downplays the severity of the adverse events, but the raw numbers remain notable relative to the tiny sample size—especially given the vaccine failed to demonstrate broad or robust neutralizing activity.

“No serious adverse reactions (SARs), suspected unexpected adverse reactions (SUSARs) or serious adverse events (SAEs) occurred. There were 15 adverse events of special interest, all of which were COVID-19 episodes which were of grade one or two severity and did not require medical attention. There were 121 unsolicited adverse events, all of which were grade one or two severity and 23 were deemed possibly, probably or definitely related to the vaccine. There were 12 laboratory adverse events considered clinically significant, all of which were grade one or two severity and self-resolved without intervention during the study.”

“All four dose concentrations of pEVAC-PS were generally well tolerated.”

Adverse-event burden is being generated in a trial so small that even a modest number of reactions changes the overall safety picture.

The authors do not provide a detailed breakdown of the specific unsolicited adverse events, raising questions about whether the paper’s reassuring “well tolerated” framing would hold up under full public disclosure of the actual reactions recorded during the trial.

Without a transparent symptom-by-symptom breakdown, readers are largely being asked to accept the authors’ safety characterization at face value.

Vaccinated Received Previous COVID Shots, Making Cause of Immunity Impossible to Determine

The trial was conducted between December 2021 and September 2023 and involved healthy adults between ages 18 and 50 who had already received two or three prior COVID-19 vaccine doses.

Since the participants were already heavily pre-immunized before receiving the experimental vaccine, the researchers themselves acknowledge they could not cleanly isolate what immune responses actually came from the new vaccine.

“Interpretation of immunogenicity outcomes was influenced by high baseline antibody levels and heterogeneous exposure histories due to ongoing waves of Omicron variant infections during recruitment, which differed across dose-escalation cohorts and introduced unavoidable immune bias,” the study reads.

The study cannot determine whether any observed immunity came from:

• the new AI-designed vaccine,
• prior COVID shots,
• prior natural infections,
• or combinations of all three.

That is why the paper ultimately falls back to cautious language like:

• “modest immunogenicity,”
• “limited boosting,”
• and merely “supporting the underlying design concept” rather than demonstrating clear protective efficacy.

The authors acknowledged the findings did “not support a robust vaccine-induced increase in antibody responses beyond pre-existing levels.”

The paper further admits the vaccine failed to produce the intended broad coronavirus immune-boosting effect:

“Although pEVAC-PS was designed to elicit cross-reactive responses against both SARS-CoV-2 and SARS-CoV-1, this intended boosting effect was not observed.”

Researchers additionally acknowledged the vaccine did not demonstrate “broad or robust neutralizing activity.”

Researchers from the University of Cambridge, University of Southampton, Imperial College London, DIOSynVax Ltd, and other institutions participated in the study.