A final analysis of the Phase 3 trial of Pfizer's coronavirus vaccine shows it was 95% effective in preventing infections, even in older adults, and caused no serious safety concerns, the company said Wednesday.
The company counted 170 cases of coronavirus infection among volunteers who took part in the trial. It said 162 infections were in people who got placebo, or plain saline, shots, while eight cases were in participants who got the actual vaccine. That works out to an efficacy of 95%, Pfizer said.
The data show Pfizer's initial claim of a better than 90% efficacy -- a claim that stunned and pleased health officials and vaccine developers last week -- holds up.
"Efficacy was consistent across age, race and ethnicity demographics. The observed efficacy in adults over 65 years of age was over 94%," Pfizer and its German partner BioNTech said in a joint statement.
"There were 10 severe cases of Covid-19 observed in the trial, with nine of the cases occurring in the placebo group and one in the BNT162b2 vaccinated group." BNT162b2 is the experimental name for the vaccine.
An independent group has been keeping an eye on results and side-effects. "To date, the Data Monitoring Committee for the study has not reported any serious safety concerns related to the vaccine," the companies said.
"The only Grade 3 (severe) solicited adverse event greater than or equal to 2% in frequency after the first or second dose was fatigue at 3.7% following dose 2," the companies said. Older adults tended to have fewer adverse events and those they had were milder.
Pfizer said it will seek US Food and Drug Administration emergency use authorization "within days."
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CNN's Sanjay Gupta explains Pfizer's 95% effectiveness rate: