Nearly all vaccines must be kept refrigerated or frozen until they are used. Maintaining that "cold chain" is expensive and, in places without reliable electricity, sometimes impossible, and large amounts of vaccine are thrown away when they get too warm. A British biotech company, Stablepharma, has developed a way to reformulate existing vaccines so they can be stored at room temperature.

The trial

In April 2025, researchers at University Hospital Southampton began what they described as the world's first clinical trial of a fridge-free vaccine: SPVX02, a tetanus-diphtheria vaccine, backed by Britain's National Institute for Health and Care Research. "For too long, vaccines have been limited by the need for refrigeration," Health Secretary Wes Streeting said. Stablepharma said it had identified about 60 vaccines that could potentially be converted to fridge-free versions.

The results

The results of the first-phase trial, published in August 2026 in the journal eClinicalMedicine, were encouraging (University Hospital Southampton; News-Medical):

  • Immune response: All 60 healthy adults in the randomized trial who received SPVX02 had protective antibody levels against both tetanus and diphtheria by day 28 — comparable to licensed vaccines.
  • Safety: There were no vaccine-related serious side effects.
  • Stability: The vaccine kept its potency for at least two years at 30°C (86°F), and remained fully effective after being cycled three times between -20°C and +40°C.

The caveats

The trial was small and enrolled only healthy adults, and the researchers say larger studies are needed. The Science Media Centre noted that a Stablepharma founder and an adviser were among the study's authors (Science Media Centre).

What happens next

A larger Phase 2b trial has begun. Stablepharma has said it hopes to make the vaccine available globally around 2027, which would make it easier to protect children against tetanus and diphtheria in remote and low-income regions.

Sources