The coronavirus vaccine developed by Pfizer and BioNTech appears to protect 94% of adults over 65 years old.
More data released from their ongoing phase three trial suggests it works equally well in people of all ages, races and ethnicities.
The companies say they will now apply for authorisation for emergency use of the jab in the US.
The findings are based on two doses given to more than 41,000 people around the world, reports the BBC.
Last week, Pfizer and BioNTech published preliminary data showing the vaccine offered 90% protection against Covid-19 and there were no safety concerns.
This was followed by impressive data on another vaccine, made by US company Moderna, suggesting nearly 95% protection.
Today’s data from Pfizer and BioNTech suggests the vaccine is 95% effective based on 170 cases of Covid-19 developing in volunteers – just eight were in the group given the vaccine, suggesting it offers good protection.
The rest of the cases were in the placebo group given a dummy jab.
The companies say there have been no serious safety concerns, but they did notice headaches and fatigue in around 2% of volunteers given the vaccine.
In the trial, 42% of all participants are from diverse ethnic backgrounds and 41% are aged between 56 and 85 years old.
The trial is still continuing, and will collect data on the safety and efficacy of the vaccine for another two years.
The vaccine is being tested on people at 150 sites in the US, Germany, Turkey, South Africa, Brazil and Argentina.
The companies expect to produce up to 50 million doses of the vaccine this year and up to 1.3 billion doses by the end of 2021.
The UK has pre-ordered 40 million doses of this vaccine and should get 10 million by the end of the year.