Pfizer Inc and its German collaborator BioNTech have said their mRNA-based vaccine candidate (BNT162b2) against SARS-CoV-2 has demonstrated over 90 per cent efficacy in those without the infection.

The critical milestone in the vaccine development programme was based on early analysis conducted on Sunday by an external, independent Data Monitoring Committee (DMC) from the late-stage Phase 3 clinical study, a note from the companies said.

Calling it a great day for “science and humanity”, Albert Bourla, Pfizer Chairman and chief executive, said: “The vaccine candidate was found to be more than 90 per cent effective in preventing Covid-19 in participants without evidence of prior SARS-CoV-2 infection in the first interim efficacy analysis.”

The development comes “at a time when the world needs it most with infection rates setting new records, hospitals nearing over-capacity and economies struggling to reopen,” he said. It is 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, he added.

“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,” the note said. This means that protection is achieved 28 days after the initiation of the vaccination, which consists of a two-dose schedule, the company explained.

FDA approval

“It’s important to note that we cannot apply for FDA (Food and Drug Administration) Emergency Use Authorization based on these efficacy results alone. More data on safety is also needed, and we are continuing to accumulate that safety data as part of our ongoing clinical study,” said Bourla, adding that data as required by the FDA would be available by the third week of November.

“Efficacy, safety and consistent manufacturing are the three requirements that are needed before we are able to file for authorisation,” he said.

“The first interim analysis of our global Phase 3 study provides evidence that a vaccine may effectively prevent Covid-19,” observed Ugur Sahin, BioNTech co-founder and chief executive. “When we embarked on this journey 10 months ago, this is what we aspired to achieve. Especially today, while we are all in the midst of a second wave and many of us in lockdown, we appreciate even more how important this milestone is on our path towards ending this pandemic and for all of us to regain a sense of normality”, he said.

Based on current projections, the two companies expect to produce globally up to 50 million vaccine doses in 2020 and up to 1.3 billion doses in 2021.

Long-term efficacy

The late-stage Phase 3 clinical trial on the vaccine candidate began late in July and has enrolled 43,538 participants to date, 38,955 of whom have received a second dose of the vaccine candidate as of Sunday. Approximately 42 per cent of global participants and 30 per cent of US participants have racially and ethnically diverse backgrounds, it added.

The study will also evaluate the potential for the vaccine candidate to provide protection against the virus in those with prior exposure to SARS-CoV-2, as well as vaccine prevention against severe Covid-19 disease. Participants will continue to be monitored for long-term protection and safety for an additional two years after their second dose, it added.