Pfizer’s COVID-19 vaccine is officially being distributed throughout the US after the Food and Drug Administration (FDA) authorized it for emergency use on December 11. Right now, the first round is being rolled out to health care workers and residents of long-term care facilities—so unless you fall into one of those two groups, you’re likely not going to get the vaccine anytime soon.

Still, the Pfizer vaccine—and any other forthcoming vaccines—are at the top of everyone’s minds, so it’s normal to have questions about the process, especially what you can expect when you get the vaccine at some point in the future. To help, the Centers for Disease Control and Prevention (CDC) has released guidance on what people can expect before, during, and after the vaccination process. Here’s what you need to know if you want to be prepared for what’s to come.

First, some COVID-19 vaccine basics:

The Pfizer COVID-19 vaccine, which is the only vaccine against the coronavirus that’s currently approved by the FDA for emergency use, uses newer technology called messenger RNA (mRNA). Biotech company Moderna also has a COVID-19 vaccine that uses mRNA, and could be granted emergency use authorization by the FDA as soon as this week, as well.

These mRNA vaccines work by encoding a part of the spike protein found on the surface of SARS-CoV-2, the virus that causes COVID-19, the Centers for Disease Control and Prevention (CDC) explains. The vaccine use pieces of the encoded protein to spark an immune response in your body. That, in turn, causes your body to develop antibodies to SARS-CoV-2, which should help you fight off the infection in the future. Afterwards, your body eliminates the protein and the mRNA, while the antibodies stick around to help provide immunity.

What should you do before you get the COVID-19 vaccine?

First, the agency recommends that you see if COVID-19 vaccination is recommended for you right now. (Again, currently, it’s only recommended that healthcare workers and nursing home residents get vaccinated, but that will change over time and with more availability.)

Then, the CDC recommends that you learn more about how the COVID-19 vaccine works and the benefits of getting vaccinated. Those benefits include helping to keep you from getting COVID-19, the vaccine being a safer way to help build protection against the virus, and helping to stop the pandemic.

Additionally, while there’s no official guidance on this,  it’s not a bad idea to take it easy the night before, infectious disease expert Amesh A. Adalja, M.D., senior scholar at the Johns Hopkins Center for Health Security, tells Health. “You don’t want to do a bunch of shots and then be hungover,” he says. His biggest concern: If you feel crappy, it could be blamed on the vaccine instead of your hangover. Also, there is a chance that the COVID-19 vaccine could cause some flu-like side effects, and you don’t want to deal with that on top of already feeling crummy, Dr Adalja says.

Another thing you don’t want to do is to take acetaminophen or ibuprofen in anticipation of potentially having side effects from the vaccine. “Nobody has studied that,” William Schaffner, MD, an infectious disease specialist and professor at the Vanderbilt University School of Medicine, tells Health. “We don’t think it would impair your immune response, but we don’t want to take any chances.”

Overall, Dr Adalja recommends following this advice: “Just do what you would normally do, within reason.”

What happens when you get the COVID-19 vaccine?

As of now, the vaccine is being given at medical centres, but that’s subject to change. There’s been some talk of dentists and optometrists vaccinating people in the future to get the vaccine out more quickly, but that hasn’t happened yet.

When you show up for your appointment to get vaccinated, the CDC recommends covering your mouth and nose with a mask and staying at least six feet away from others (until, of course, it’s time to be vaccinated).

The actual vaccination process will be similar to how it’s been when you’ve gotten a flu shot or most other vaccines, John Sellick, DO, an infectious disease expert and professor of medicine at the University at Buffalo/SUNY in New York, tells Health. Meaning, a spot on your upper arm will be sterilized with rubbing alcohol or something similar, and you’ll receive your injection.

“You will be asked to wait around for 15 minutes or so to make sure you don’t have a reaction,” Dr Schaffner says. This is technically also a recommendation with the flu shot, but many places don’t enforce it, he says, adding, “I think this will be observed with the COVID-19 vaccine, just to be safe.”

Then, the CDC says that should receive a vaccination card or printout that tells you what COVID-19 vaccine you received, the date you received it, and where you received it. You should also receive a paper or electronic version of a fact sheet that tells you more about the specific COVID-19 vaccine you are being offered. (Again, as of this second, only the Pfizer-BioNTech COVID-19 vaccine has been authorized by the FDA.)

“After that, you can go about your merry way,” Dr Sellick says.

What can you expect after you get the COVID-19 vaccine?

You won’t be considered fully vaccinated against COVID-19 until you get a second shot, which is usually given a few weeks later. And you’ll have to talk to your provider for the specifics on that.

You may experience some side effects after getting vaccinated. These are the most common side effects of the COVID-19 vaccine, per the CDC:

• Pain at the injection site
• Swelling in the arm where you got your shot
• Fever
• Chills
• Tiredness
• Headache

If you have arm soreness or swelling, the CDC recommends holding a clean, cool, wet washcloth over the area, and using or exercising your arm. If you have a fever, the CDC suggests drinking plenty of fluids and dressing lightly. And, if you have pain or discomfort, the CDC says it’s a good idea to talk to your doctor about taking an over-the-counter medicine like ibuprofen or acetaminophen.

In general, the side effects—if you even experience them—should go away in a day or two, Dr Schaffner says. But the CDC recommends calling your healthcare provider if the redness or tenderness where you got the shot increases after 24 hours or if your side effects are worrying you or don’t seem to be going away after a few days.

The CDC recommends that you get the second shot even if you have side effects after the first one unless a vaccination provider or your doctor tells you not to get a second shot.

The CDC also recommends that you sign up for V-safe, a free, smartphone-based tool that uses text messaging and web surveys to provide personalized health check-ins after you receive the vaccine. It also reminds you to get your second dose.

Even with two shots, it can take a little time for your body to build up immunity to COVID-19. The CDC says that both shots may not protect you until “a week or two” after your second shot.

Even after you’ve gotten to that point, Dr Adalja says it’s still important to wear a mask in public and follow other methods of preventing the spread of COVID-19. The vaccine isn’t 100% perfect, after all, and it’s unclear at this point whether you can still spread the virus after you’ve been vaccinated. “Keep following recommendations until public health officials advise otherwise,” Dr Adalja says.