Dec. 8 (UPI) -- Pfizer's COVID-19 vaccine offers more than 50% protection against the virus within 10 days of receiving the first dose, according to documents released Tuesday by the U.S. Food and Drug Administration.
Data posted online by the FDA also suggests that the vaccine works well irrespective of recipients' race, weight or age.
This is significant, given research has found that people of color, those who are overweight or obese and the elderly are at increased risk for infection and serious illness with COVID-19.
The review of existing study data on the safety and efficacy of the Pfizer vaccine is being conducted as part of the drugmaker's application for an emergency use authorization for the two-dose shot.
Earlier this month, Pfizer, which developed the vaccine in partnership with Germany-based BioNTech, announced that the vaccine was more than 95% effective preventing infection with the new coronavirus after two doses.
However, the data posted on the FDA web site on Tuesday indicates that the shot offered 52% of recipients protection against infection within 10 days of the first dose.
The two vaccine doses are intended to be administered 21 days apart. The FDA's vaccine advisory panel is scheduled to review the data Thursday before voting on whether to approve the emergency use authorization for the vaccine.
The federal government has agreed to purchase 100 million doses of the Pfizer vaccine, enough to inoculate 50 million people.
The FDA also is scheduled to hold a hearing Dec. 17 on Moderna's emergency use application application for its vaccine, which the company claims also is more than 90% effective at preventing COVID-19 infection.
Both vaccines require cold storage -- Pfizer's at minus-94 degrees C and Moderna's at minus-4 degrees C -- to remain effective. Special freezer units are being distributed across the country in anticipation of their FDA approval, officials have said.
With vials and doses already in production, some hope exists that initial doses of one or both shots could be administered before the end of December, with elderly residents of nursing homes and healthcare workers given first priority.