ATLANTA — There are two different types of COVID-19 vaccine that are being rolled out for emergency use around the world.
The first one that was authorized by the Food and Drug Administration came from Pfizer and began shipment on Sunday from its plant in Kalamazoo, Mich.
A second vaccine that may receive emergency use declaration from the FDA is from Moderna.
Both vaccines require two separate doses for full effectiveness.
Following an initial injection, the Pfizer vaccine must be followed up with a second shot 21 days later. The Moderna vaccine requires a first shot followed by a second jab 28 days later.
This is not an unusual situation. Other vaccination courses, like forms of the hepatitis vaccine and others, necessitate multiple courses for full effectiveness.
Now that the COVID-19 vaccine is being rolled out around the nation, there are other questions that are being raised.
Once vaccinated, is it possible for an individual to pass COVID-19 on to someone else?
The short answer is that it is too early to say.
According to medical experts, it is not known if individuals may be able to become asymptomatic; or in other words, become carriers of the illness without becoming ill.
"It remains possible that if you're vaccinated, you could actually develop asymptomatic infections, so you feel well and have no symptoms, but potentially you could spread the virus to others," said Dr. Thomas Russo of the University of Buffalo's Department of Infectious Diseases.
RELATED: VERIFY: Will the COVID-19 vaccine stop you from spreading it to others? Experts don't know yet
More data and monitoring needs to take place to ensure that if, in fact, the virus replicates a vaccinated, non-symptomatic individual can't infect someone else.
After vaccination, do individuals still need to wear masks in public?
Since we don't know if vaccinated individuals can spread the virus, it is still incumbent to wear masks in public and continue to practice social distancing in order to protect those around us from the virus.
In addition, it will take months for everyone to receive the vaccination, so there will be an extended period when some will have been vaccinated and others have not.
How effective are the vaccines?
Out of the two vaccines that are currently being put into circulation -- according to Pfizer, its vaccine is 94.5% effective in clinical trials. Moderna says its vaccine is 95% effective.
Another vaccine that may be approved down the road, developed by AstraZeneca and Oxford University, is said to be about 70% effective.
How long does protection last after being vaccinated?
That's another question that is not completely clear.
Those taking part in the Phase 3 clinical trials and the first folks to get vaccinated may eventually to be able to provide the answer to that question, according to researchers at Johns Hopkins University.
Epidemeologist Dr. Anthony Fauci said he would be surprised if the vaccine gave life-long immunity like the measles vaccine.
Moncef Slaoui, head of the US vaccine development effort said he believes the effectiveness could last for "many, many years," with older people and others who are more vulnerable requiring a booster shot every three-to-five years.
What about side effects of the vaccine?
According to a handout from the CDC, on the arm where you get the shot, some pain and swelling are common. They said that throughout the rest of the body, fever, chills, tiredness, and headache are not uncommon.
They said in most cases, discomfort from fever or pain is normal. If redness or tenderness increases after 24 hours or if the side effects are worrying or do not seem to be going away after a few days, patients are advised to contact a medical professional.
Can you get COVID-19 from the vaccine?
The CDC said that none of the vaccines that have been in development use the live virus that causes COVID-19. The goal of each of the vaccines is to teach our immune systems to recognize and fight the virus that causes the coronavirus. Sometimes this process can cause symptoms, such as fever. These symptoms are normal and are a sign that the body is building immunity.
Can you still donate blood and plasma after receiving a vaccine?
According to the December 2 update from the American Association of Blood Banks and the FDA, people who receive a vaccine can still donate blood, but not convalescent plasma.
Convalescent plasma is human plasma collected from individuals whose plasma contains COVID-19 antibodies, and who meet all donor eligibility requirements and qualifications.
Should you get the vaccine if you have already had COVID-19?
According to Dr. Stuart Ray from Johns Hopkins University, getting vaccinated is an extra layer of protection.
“Based on what we know, right now, it's likely that a vaccine would be recommended for a person who's had COVID, because we don't think that prior infection is likely to generate lasting immunity," Ray said. "There's lots of ways people might think that they are immune, and given the stakes, it seems a good idea to be really sure. And so if the vaccine is found to be safe and effective, and we wouldn't offer it otherwise, then it seems likely that we would recommend it."
Should pregnant women get the vaccine?
Pregnant women were excluded from participating in the Pfizer and Moderna studies, so it is not known how they would be impacted.
During Pfizer's study, 23 women became pregnant during the study and nine of them dropped out as a result. The remainder are still being followed.
The American College of Obstetricians and Gynecologists said on Sunday that vaccination should not be withheld from pregnant women who otherwise would qualify.
The bottom line is that it's up to you and your doctor to make that decision.
When will the general public be able to get the vaccine?
According to Dr. Anthony Fauci, average Americans are not likely to be able to get the COVID-19 vaccine until around March or April 2021.
Supply and worldwide demand will play a factor.
Additional supplies will become available as more vaccines are approved.
Canada and the U.K. had approved the Pfizer vaccine ahead of the United States.
The CDC said a coronavirus vaccine for young children may not be available until more studies have been completed.