The release of updated results comes on the heels of separate data that showed the vaccine is safe and effective in 12 to 15-year-olds, paving the way for the drugmakers to seek United States and European approval to use the shot in this age group within weeks.
The updated topline results show that the Pfizer vaccine is 91.3 per cent effective against Covid-19, seven days through up to six months after the second dose.
The vaccine, given in two doses three weeks apart, is already cleared for emergency use in people ages 16 and up.
Last week, the companies gave the first vaccine doses in a series of trials testing it in younger children, including those as young as six-months-old.
"In South Africa, where the B.1.351 lineage is prevalent and 800 participants were enrolled, nine cases of Covid-19 were observed, all in the placebo group", the companies said.
This story was first published on CNN.com, "Pfizer says Covid-19 vaccine protection lasts at least six months, protects against variants".
"These data confirm the favorable efficacy and safety profile of our vaccine and position us to submit a Biologics License Application to the U.S. FDA", Albert Bourla, Pfizer's chairman and chief executive officer, said in a statement. Time will tell, ' Fauci told CNN.
A second study, the largest study on antibody and cellular immune factors to date, suggests people are likely to be protected against the Wuhan, Kent and Brazilian types of coronavirus following two doses of the Pfizer jab.
"We share the urgency to expand the authorization of our vaccine to use in younger populations and are encouraged by the clinical trial data from adolescents between the ages of 12 and 15", Bourla said.
'From the 927 confirmed symptomatic cases of COVID-19 in the trial, 850 cases of COVID-19 were in the placebo group and 77 cases were in the BNT162b2 group, corresponding to vaccine efficacy of 91.3%,' it said.
Pfizer CFO Frank D'Amelio said that the COVID-19 vaccine might have to shift gears if the virus becomes endemic to our society.
As many as 7,06,18,026 vaccine doses were administered till 8 pm, including 6,13,56,345 people who received their first dose. And there are different vaccines out there with different efficacy against COVID-19 variants.
"The antibody levels were so high that they'd gone above the thresholds so they had to dilute them". And the combination of having very high levels of antibodies and persistent levels of protection are the recipe for a very long level of protection against these variants, ' Hensley added.
Plus, vaccines often aren't effective forever - the COVID-19 vaccine might be a semi-annual or annual vaccine that we need to get like the flu.
Both Pfizer and Moderna use a technology called messenger RNA or mRNA delivery as the basis of their vaccines.
"Will it be 100 percent efficacious in the real world?"