Coronavirus vaccine manufacturer Pfizer has claimed its vaccine is more than 90% effective in preventing Covid-19 during a major trial.

The pharmaceutical firm, developing the mRNA-based vaccine with BioNTech, achieved the results during phase three clinical study.

The study enrolled 43,538 participants who had no evidence of prior infection – 42% of whom having a diverse background – and saw no serious safety concerns observed.

The case split between vaccinated individuals and those who received the placebo indicates a vaccine efficacy rate above 90%, at seven days after the second dose.

It confirmed 94 cases of Covid-19 in trial participants, although interim analysis of the phase is continuing.

Dr Albert Bourla, CEO of the American company, said “today is a great day for science and humanity”.

Dr Bourla said: “The first set of results from our phase three Covid-19 vaccine trial provides the initial evidence of our vaccine’s ability to prevent Covid-19.

“We are reaching this critical milestone in our vaccine development programme at a time when the world needs it most with infection rates setting new records, hospitals nearing over-capacity and economies struggling to reopen.

“With today’s news, we are a significant step closer to providing people around the world with a much-needed breakthrough to help bring an end to this global health crisis. We look forward to sharing additional efficacy and safety data generated from thousands of participants in the coming weeks.

“I want to thank the thousands of people who volunteered to participate in the clinical trial, our academic collaborators and investigators at the study sites, and our colleagues and collaborators around the world who are dedicating their time to this crucial endeavour.

“We could not have come this far without the tremendous commitment of everyone involved.”

The UK has secured 40 million doses of the Pfizer/BioNTech vaccine - the first agreement the firms signed with any government.

It is reported people will need two doses, meaning not enough shots have yet been secured for the entire UK population.