PHARMACEUTICAL giant Pfizer and biotech firm BioNTech have said their coronavirus vaccine was more than 90 per cent effective in preventing Covid-19 among those without evidence of prior infection.

The results are based on the first interim analysis of Phase 3 of the study and evaluated 94 confirmed cases of Covid-19 in trial participants.

The study enrolled 43,538 participants, with 42 per cent having diverse backgrounds, and no serious safety concerns have been observed, the companies report.

They add that safety and additional efficacy data continue to be collected.

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

Researchers say this means that protection is achieved 28 days after the initiation of the vaccination, which consists of two doses.

However, they caution that as the study continues the final vaccine efficacy percentage may vary.

Dr Albert Bourla, Pfizer chairman and chief executive, said: “Today is a great day for science and humanity.

“The first set of results from our Phase 3 Covid-19 vaccine trial provides the initial evidence of our vaccine's ability to prevent Covid-19.”

He added: “We will continue to collect further data as the trial continues to enrol for a final analysis planned when a total of 164 confirmed Covid-19 cases have accrued.

“I would like to thank everyone who has contributed to make this important achievement possible.”

Their vaccine has been tested on 43,500 people in six countries and no safety concerns have been raised.

The companies plan to apply for emergency approval to use the vaccine by the end of the month.

A vaccine – alongside better treatments – is seen as the best way of getting out of the restrictions that have been imposed on all our lives.

There are around a dozen in the final stages of testing – known as a phase 3 trial – but this is the first to show any results.