(ABC4) – The Pfizer COVID-19 vaccine is the first to receive full approval from U.S. regulators. On Monday, the Food and Drug Administration approved the coronavirus vaccine, saying this “signifies key achievement for public health.” Now that the Pfizer vaccine has reached full approval status, here are some things to know about the shot, per the FDA.

How did the FDA decide to give the Pfizer COVID-19 vaccine full approval and what makes it different from the emergency authorization approval the vaccine received in December 2020?

According to the FDA, data and information submitted by Pfizer for the Comirnaty – COVID-19 vaccine mRNA – was received to determine if the vaccine is safe and effective in preventing coronavirus in those 16-years-old and older. In December, the Pfizer vaccine was approved for emergency use based on clinical trials in about 36,000 people – 18,000 received the vaccine while the rest received a placebo. The COVID-19 vaccine was 95% effective in preventing the disease with eight of those in the vaccinated group getting COVID-19 and 162 in the placebo testing positive. An updated analysis of about 40,000 people – half getting the vaccine – found the Pfizer dose was 91% effective after 77 with the shot got the virus. In that placebo group, 833 COVID-19 cases were reported.

How effective is the Pfizer COVID-19 vaccine?

According to the FDA, the Pfizer vaccine is 91% effective in preventing COVID-19 disease. Commonly reported side effects of this vaccine were pain, redness, and swelling at the injection site, as well as fatigue, headache, muscle pain, joint pain, and fever.

The FDA says they also evaluated data regarding some who received the Pfizer vaccine suffering from myocarditis – inflammation of the heart muscle – and pericarditis – inflammation of a sac-like structure with two thin layers of tissue surrounding the heart, according to the American Heart Association. They found an increased risk, particularly within the seven days following the second dose of the Pfizer vaccine. The risk is higher among men under the age of 40-years-old and highest among males between the ages of 12 and 17. While short-term follow up data shows most individuals “had resolution of symptoms,” the FDA says some individuals required intensive care support. There is not yet information about the potential long-term health outcomes.

Can those under the age of 16 still get the Pfizer COVID-19 vaccine? What about third doses for the immunocompromised?

While the FDA’s full approval is specifically for the use of the Pfizer COVID-19 vaccine in those 16-years-old and older, the emergency use authorization remains in effect for teenagers between the ages of 12 and 15. Additionally, emergency use authorization is still available for vaccinated, immunocompromised individuals seeking a third dose based on guidance from the CDC.

How long will the Pfizer COVID-19 vaccine protect me from the virus?

In April, Pfizer announced its COVID-19 vaccine remains effective for at least six months.

For more frequently asked questions about the Pfizer COVID-19 vaccine, visit the FDA’s website.