One striking chart shows just how well Pfizer's vaccine works to prevent COVID-19 infections

• The FDA released data about Pfizer's new coronavirus vaccine on Tuesday.
• The data suggests the company's 2-shot course works very well at preventing COVID-19 infections.
• One chart in the brief suggests protection from infection begins 14 days after a person's first shot, and that protection gets much better after their second dose is administered.
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The US Food and Drug Administration released safety and efficacy data on Pfizer's novel coronavirus vaccine to the public on Tuesday - and it's looking good. 

In a 53-page briefing document posted on its website, the FDA data showed that Pfizer's mRNA vaccination course worked well in more than 40,000 people of various ages, races, and sexes who tested it out in six different countries around the world. 

One chart in the briefing materials documents how many people during the study got COVID-19, the disease caused by the novel coronavirus. Comparing those who got the Pfizer treatment to those in the control group, it shows just how well the new 2-shot vaccine course can work at preventing infections.

The red line in the chart represents how many of the roughly 21,000 participants in the control group - those who (unknowingly) received a bogus (placebo) shot - got sick. The blue line shows rates of COVID-19 infection in the other half of the study, among the roughly 21,000 people who received the real Pfizer shot. 

The chart suggests people who got the real Pfizer vaccine started to gain protection from infection beginning 14 days after their first shot. Then, 21 days in, they got their second (and final) shot. After that, they were protected well from infection for at least two more months.

The vaccine's protection possibly lasts much longer than that, it's just too soon to know for sure.

The vaccine's protection gets a lot better with a second shot 

It takes some time for shots to take effect in the body, providing robust and full protection against the virus. Because of this, after the first Pfizer shot was administered, nearly 90 people who got the vaccine became sick with COVID-19 before receiving their second shot. 

But starting one week after the second shot was given, the vaccine became much more effective at preventing infections.

Only 8 people got COVID-19 after receiving both doses of the Pfizer vaccine, and waiting a full week for the vaccination to take effect (roughly 28 days from the start of the trial). Only one person among those 8 suffered a severe case of the disease; they were not hospitalized.

Meanwhile, in the control group with no protection, cases continued to climb. After day 28, they recorded 163 more infections, with three severe cases, including two hospital admissions (one in the ICU).

The FDA is scheduled to hold an advisory committee meeting on Thursday, to decide whether the agency will approve - or reject - what would be America's first emergency-authorized vaccine for COVID-19. Pfizer's vaccine has already been approved for use in the UK and Bahrain.