Pfizer says Covid-19 vaccine found to be “more than 90% effective” 2 years ago

Pfizer says Covid-19 vaccine found to be “more than 90% effective”

“Today is a great day for science and humanity.”

A global clinical trial of a Covid-19 vaccine has been found to be more than 90% effective, according to manufacturers Pfizer and BioNTech.


The first set of results from the Phase 3 Covid-19 vaccine trial were announced by Pfizer on Monday (9 November), a day described as “a great day for science and humanity” by Dr. Albert Bourla, Pfizer Chairman and CEO.

The results revealed that the vaccine candidate was found to be more than 90% effective in preventing Covid-19 in participants without evidence of prior infection, in analysis by an external, independent Data Monitoring Committee.

The figure of over 90% is hugely significant as regulators have previously discussed a willingness to approve a vaccine that is 50% effective, thereby protecting only half of those who would get it.

The global trial, which began in July, involved 43,538 participants, 42% of whom were said to come from “diverse backgrounds”.


The analysis evaluated 94 confirmed cases of Covid-19 in trial cases. Pfizer says that 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.

This, Pfizer says, means that protection is achieved 28 days after the initiation of the vaccination, which consists of a two-dose schedule.

The study will continue until there is final analysis of 164 confirmed cases in order to collect further data and characterise the vaccine candidate’s performance.

The potential for the vaccine to provide protection against Covid-19 in those who have had prior exposure to the virus, as well as vaccine prevention against severe Covid-19 disease, will also be explored as the study continues.


To date, the independent Data Monitoring Committee has not reported any serious concerns or side effects and data collected will be discussed with regulatory authorities around the world.

Pfizer and BioNTech say they are currently working to prepare the necessary safety and manufacturing data to submit to the US Food and Drug Administration (FDA) to demonstrate the safety and quality of the vaccine product produced.

Once the required safety milestones are reached - currently expected to be the third week of November - the vaccine will be submitted for Emergency Use Authorisation (EUA) to the FDA.

“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,” said Dr. Albert Bourla.


“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,” Bourla added.

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

Based on current projections, Pfizer and BioNTech say they expect to produce up to 50 million vaccine doses globally in 2020 and up to 1.3 billion doses in 2021.

Data from the full Phase 3 trial will also be submitted by Pfizer and BioNTech for scientific peer-review publication.