New mpox vaccine shows promising early results in first human trial
The first clinical trial of a new vaccine designed to protect against mpox has reported encouraging early results.
The study tested an mRNA-based candidate vaccine called BNT166a in healthy adult volunteers.
Researchers found that the vaccine was generally safe and well tolerated.
Crucially, the vaccine also triggered a strong immune response, producing antibodies capable of recognising and fighting the virus.
These responses were seen across all dose levels and in both people who had and had not previously been vaccinated against related viruses.
The international trial was led by University Hospital Southampton, with participants taking part at three NIHR Clinical Research Facilities as well as two sites in the USA.
Researchers have published their findings in The Lancet Infectious Diseases.
New generation of vaccines
Mpox (formerly known as monkeypox) is a viral infection that can cause painful skin lesions and, in some cases, serious complications. Recent global outbreaks have highlighted the need for new, scalable vaccines that can be rapidly deployed to protect populations at risk.
This new vaccine uses mRNA technology, similar to that used successfully in COVID-19 vaccines. It works by teaching the body to recognise specific proteins from the virus, helping the immune system respond quickly if exposed. It has been developed by life sciences company BioNTech.
Professor Saul Faust, UK Chief Investigator for the trial and Director of the NIHR Clinical Research Facility: Southampton, said:
“These findings are an important step forward in the development of a new generation of vaccines against mpox. We’ve shown that this mRNA vaccine approach can safely generate strong immune responses in people, which is very encouraging.
“The trial results also showed some initial evidence that the vaccine might provide some protection against different clinical strains that have occurred in human outbreaks.
“While further studies are needed, this brings us closer to having more effective and adaptable tools to respond to outbreaks and protect vulnerable communities.”
First-in-human trial
The trial was designed primarily to assess safety and immune responses, rather than how well the vaccine prevents infection.
A total of 64 people took part, including 48 participants who had not previously been vaccinated against related viruses and a further 16 who had.
Most side effects were mild to moderate and short-lived.
UK participants were seen at the NIHR Southampton Clinical Research Facility at University Hospital Southampton NHS Foundation Trust, the NIHR Cambridge Clinical Research Facility at Cambridge University Hospitals NHS Foundation Trust, and the NIHR Royal Surrey Clinical Research Facility at Royal Surrey NHS Foundation Trust.
Professor Krishna Chatterjee is Director of the NIHR Clinical Research Facility: Cambridge. He is also a Consultant Endocrinologist at Cambridge University Hospitals and Professor of Endocrinology at the University of Cambridge.
He said: “This trial showed how UK Government investment in early-phase trial facilities can support industry to rapidly test new vaccines and medicines before proceeding to larger scale trials.”
The vaccine is now progressing to a larger trial to confirm its effectiveness in real-world settings.