select search filters
briefings
roundups & rapid reactions
Fiona fox's blog
Results of a phase 1 trial published in eClinicalMedicine looks at the safety and tolerability of a tetanus-diphtheria vaccine.
Prof Linda Klavinskis, Professor of Viral Immunology, King’s College London, said:
“The data from this phase 1 clinical trial of a thermostabilised tetanus-diphtheria vaccine are encouraging; the study is solid in terms of safety and short-term immune responses reported. The real-world impact claims are a bit premature, since the study only shows immunogenicity at 28 days post vaccination, which is not the same as longer term immune durability i.e. real-world effectiveness. As such, studies with a larger sample size and longer follow-up will be required to evaluate effectiveness of this stabilised vaccine for real-world protection.”
Dr Hamid Merchant, pharmaceutical scientist and Head of Department for Biosciences, University of East London, said:
“The most important finding is that the vaccine appears to produce safety and immunogenicity profiles similar to existing tetanus-diphtheria booster vaccines while potentially removing one of the biggest barriers to global vaccination – the dependence on the cold chain.
“Cold-chain requirements remain a major contributor to vaccine wastage, logistical complexity and cost, particularly in resource-limited settings. A vaccine that can be stored at room temperature and withstand temperature excursions could have important global public health benefits.
“The trial has several strengths, including a randomised design and the use of two licensed active comparator vaccines rather than placebo. However, it remains an early-stage study involving only 20 healthy adults in each vaccine group who were followed for only 28 days. The study was not powered for formal statistical comparisons between vaccine groups.
“Another important limitation is participant diversity. Around 95% of participants were white and all were healthy adults aged 18 to 55 years. Larger and more representative studies will be needed before the findings can be confidently generalised to wider populations.
“It is also important to note that the claim that the vaccine is ‘unaffected by freezing’ is supported by laboratory stability and freeze-thaw studies rather than direct clinical evaluation of vaccine exposed to such conditions before administration.
“The human trial demonstrates that room-temperature-stored SPVX02 remained safe and immunogenic, whereas the longer-term stability claims derive from separate laboratory stability programmes. While the vaccine was reported to have been stored at room temperature during the trial, the paper does not specify when the clinical batch was manufactured or how long it had been stored before administration.
“From a pharmaceutical science perspective, the scientific interest lies in the formulation technology rather than the vaccine itself. However, the paper provides limited detail on how thermostability was achieved, and it remains unclear how the clinical-trial formulation relates to the proprietary sponge-based stabilisation platform described in earlier publications.
“Therefore, an important unanswered question is whether the stability advantage can be delivered through a conventional vaccine-in-a-vial manufacturing process that is sufficiently simple, cost-effective and transferable to achieve the global health impact envisaged by the authors.
“Overall, this is a promising proof-of-concept study. The real test will be larger Phase 2/3 trials, longer follow-up, greater population diversity, and further transparency around the formulation and manufacturing platform. If those data are positive, the implications could extend well beyond tetanus-diphtheria vaccines to other aluminium-adjuvanted vaccines where cold-chain dependence remains a major global challenge.”
Prof Tuck Seng Wong, Professor of Biomanufacturing, University of Sheffield; and Director, UK-Southeast Asia Vaccine Manufacturing Research Hub, funded by DHSC and EPSRC, said:
“This very exciting study addresses one of the greatest challenges in biopharmaceuticals – the cold-chain requirement for biologics including vaccines.
“Through reformulation and lyophilisation, the authors demonstrate that vaccines can potentially be stored at 30°C for up to 24 months while retaining their potency, a significant breakthrough in UK science.
“Importantly, the strategy appears to be biomolecule-agnostic, suggesting that it could be broadly applicable to a wide range of biologics.
“In my view, this is where its true value and potential impact lie.
“Despite these exciting findings, several areas warrant further investigation. Many low- and middle- income countries (LMICs) experience temperatures well above 30°C, as well as substantial temperature fluctuations between day and night.
“It therefore remains to be seen whether the reformulated and lyophilised vaccine can maintain its stability at higher temperatures and, importantly, whether it is robust enough to withstand significant temperature fluctuations during storage and distribution.
“The relatively small clinical trial size (20) is another consideration, particularly given that most participants self-identified as White.
“If this technology is to help address global health challenges, greater ethnic diversity in clinical evaluation will be important to establish its broader applicability and relevance, particularly in LMIC populations.”
‘Safety, tolerability, and immunogenicity of SPVX02, a room temperature-stabilised tetanus-diphtheria vaccine, compared to two established tetanus-diphtheria booster vaccines: a multicentre, single-blind, randomised, first-in-human phase 1 trial in the UK’ by Thomas A. N. Reed et al. was published in eClinicalMedicine at 23:30 UK time on Wednesday 5 August 2026.
DOI: 10.1016/j.eclinm.2026.104116
Declared interests
Prof Linda Klavinskis: “No COIs.”
Dr Hamid Merchant: “Dr Hamid A. Merchant is Head of Department for Bioscience at the University of East London and has held adjunct professorships at the Health Services Academy, Ministry of National Health Services, Regulations and Coordination, Government of Pakistan, and at Dow Life Sciences, Dow University of Health Sciences. Dr Merchant has extensive experience collaborating with and undertaking projects for the pharmaceutical industry through previous academic and professional roles and has previously worked for Abbott Laboratories Ltd before joining academia.
No funding was received to commission, support, or influence the preparation of this work. Dr Merchant declares that he has no financial, personal, or professional competing interests directly related to this study or to the opinions, comments, and responses presented herein.”
Prof Tuck Seng Wong: “No conflict of interest to declare.”
This Roundup was accompanied by an SMC Briefing.