A vaccine could train the immune system to fight coronavirus, according to US scientists.

Neutralising antibodies have been found in the first eight people who took part in safety trials for the experimental mRNA-1273 vaccine.

The drug, being tested by firm Moderna, injects a small sample of Covid-19’s genetic code into patients.

The amount is enough to encourage a response from the immune system and the trials are expected to be rolled out more widely in the summer.

Tal Zaks, chief medical officer at Moderna, said: “These interim Phase 1 data, while early, demonstrate that vaccination with mRNA-1273 elicits an immune response of the magnitude caused by natural infection starting with a dose as low as 25 micrograms.”

He added: “These data substantiate our belief that mRNA-1273 has the potential to prevent Covid-19 disease and advance our ability to select a dose for pivotal trials.”

The sentiments were echoed by CEO Stephane Bancel, who added: “With today’s positive interim Phase 1 data and the positive data in the mouse challenge model, the Moderna team continues to focus on moving as fast as safely possible to start our pivotal Phase 3 study in July.”

Professor Robin Shattock, Professor of Mucosal Infection and Immunity, Imperial College London, called the early results “encouraging”.

He added: “While it will be important to scrutinise the actual data, the reported findings are in line with expectations that vaccine candidates should provide levels of neutralising antibodies that are at least equivalent to convalescent subjects.

“This is a promising start, but efficacy data will be key followed by an ability to scale in a manner that provides global access should this vaccine be successful.”