What Happens To Your Body When You Take The Pfizer COVID-19 Vaccine

The coronavirus pandemic has been with us for quite some time, but while we've been growing used to stay-at-home orders, business closures, all-day Netflix binging, and sweatpants wearing, scientists and medical professionals have worked to create a number of different vaccines, all in record time. Two vaccines from separate companies were given emergency authorization in the United States. One such vaccine was the Pfizer vaccine, a two-part vaccination that, at the time of this writing, has been administered to over 86 million people across the country (via the Centers for Disease Control).

So what is the process of getting the Pfizer COVID-19 vaccine? What does it consist of? What impact does it have on the body? These are all questions that people are wanting the answers to, given that vaccinations are now happening across the country.

The Pfizer vaccine is being administered, like the other vaccines available, to certain age groups, essential workers, and people with preexisting conditions across the United States. With time, more states are expanding their eligibility, leading to more vaccinated people in the near future. So here's everything you need to know about what happens to your body when you receive the Pfizer COVID-19 vaccine.

Some people have been wondering if there are any steps you need to take before getting the Pfizer vaccine. Like many other vaccines, like the flu shot, there isn't really any prep work on your part that needs to be done. Simply show up to your appointment wearing a shirt with a sleeve that is easy to roll up and get ready for a pretty quick, little jab in the arm.

However, the one step that people can take involves their medical history.  Prior to receiving the vaccine, people should identify any ingredients within the Pfizer COVID-19 vaccine that they might be allergic to. Pulmonary medicine specialist Dr. Jafar Abunasser told Health Essentials that common allergies like hay fever or nut allergies aren't an area of concern, but if you have hesitations, talk to your doctor. "I will always tell someone who has an immunologist to talk about their concerns with their doctor since they know your individual case," Dr. Abunasser said, "and can tell from your records or tests what you are actually allergic to."

There has been a little bit of confusion about the two-step process associated with the Pfizer vaccine, so here's the info. The manufacturer of the vaccine is Pfizer, Inc. and BioNTech. It is an mRNA vaccine and must be administered in two different shots, each shot being 21 days apart. It's given in the upper arm, and it can be administered to anyone 16 and older, as recommended by the Centers for Disease Control. After the first dose, the second should be given after 21 days but before 42 days for "optimal vaccine effectiveness," as concluded by the Morbidity and Mortality Weekly Report from the CDC on March 15, 2021. 

So why the two shots? As noted by Healthline, the mRNA vaccine works with the cells in your body and creates the proteins necessary to keep your body functioning well. The mRNA that is in the Pfizer vaccine gives your body's cells a set of instructions that it then uses to create the "spike protein" that works to protect you from COVID. So you heard it here: If you're getting the Pfizer COVID-19 vaccine, make sure you go for that second appointment.

For anyone concerned about potentially having an allergic reaction to the Pfizer vaccine, consult with your doctor, as aforementioned. However, if your doctor clears you for the vaccine and you still have an immediate allergic reaction, it will materialize within four hours of the vaccine being administered, according to the Centers for Disease Control. The CDC suggests that if you have ever had a serious and/or immediate allergic reaction to any of the included ingredients in the vaccine, you should not get the COVID vaccine. Similarly, if you have an immediate allergic reaction to your first Pfizer COVID-19 vaccine — even if it's not serious — you should not get the second dose. 

So what constitutes a serious allergic reaction? If you have to go to the hospital due to your reaction or you have to use an EpiPen, then you fall under the severe allergic reaction category. While everyone reacts slightly differently, an allergic reaction to the vaccine can consist of swelling, hives, and respiratory problems like wheezing. So make sure you check that ingredient list before making your appointment.

When you get the Pfizer coronavirus vaccine, you should be aware of the common side effects. Like the flu vaccine, the Pfizer jab goes into the upper part of your arm, and there are some common side effects that may present themselves at the area at which it's administered. According to the Centers for Disease Control, you may experience redness, pain, or swelling in the area where you received the vaccine. Of course, everyone is different, so you may experience these side effects or you may not — it varies person to person.

There are some other side effects that should be noted that impact other areas of your body, rather than just the point of vaccination. After the Pfizer COVID-19 vaccine, you may experience side effects including chills, nausea, tiredness, headaches, muscle pain, and fever. According to the CDC, the side effects usually materialize within a day or so of getting the vaccine and should go away in a couple days. So maybe plan to take it easy for the few days after your appointment. Even if you don't get side effects, some downtime at home with Netflix is always a good idea.

Given that the point of vaccination on your upper arm can get a little sore after you receive the Pfizer COVID-19 vaccine, it doesn't come as a surprise that people have wanted to take painkillers after the fact. The good news is that you can take painkillers like ibuprofen or aspirin after you get the vaccine. According to the Centers for Disease Control, you shouldn't have any concerns about taking an over-the-counter pain medication, especially if you have no other medical reasons that would cause you to normally be wary of painkillers. However, it is very important to note that the CDC does not recommend taking any kind of pain medication before getting the Pfizer vaccine as a way to diminish side effects. 

Dr. Jafar Abunasser, a pulmonary medicine specialist, told Health Essentials that trying to avoid side effects by taking a painkiller before the vaccine is a no-go and that you should wait to address side effects only when you experience them. "You don't prepare for the side effects. Instead, you would monitor for them after you've been vaccinated," he said.

Like a lot of vaccines that we're used to getting — the flu shot, the chickenpox vaccine, etc. — the Pfizer COVID-19 vaccine comes with temporary setbacks. Dealing with a slight fever, body aches, and area soreness (among other side effects) is never fun, and while most post-vaccine symptoms should go away quickly, it's important to know how to treat your body. Good thing for people who have been vaccinated or are waiting for their turn, the Centers for Disease Control has a list of practices you can do to help heal from the vaccine as quickly as possible. 

Let's break it down. Your arm could be a bit sore, red, or swollen at and around the area you were given the actual shot of the Pfizer vaccine. In order to help with these side effects, it's recommended to apply a cool, clean, wet washcloth and let it work its magic. It is also important to exercise and use your arm like you normally would. In the aftermath of the vaccine, you should dress lightly (especially if you have a bit of a fever) and be sure to drink a lot of water.

Side effects for people who have been administered the Pfizer vaccine are normal occurrences, and some people don't get any kind of post-vaccine symptoms at all. As noted by the Centers for Disease Control, the discomfort that you feel from the vaccine — especially the fever — is actually a good sign. It means that your body is adapting to the vaccine. But if you do get the vaccine and your body reacts in a severe way, you should call and consult your doctor.

If the area where you got the vaccine continues to be sore, red, and tender and gets worse a full 24 hours after the jab, you should talk to your doctor. It is also recommended to speak to a medical professional if you are worried about the side effects you're experiencing or if your body's reaction to the shot — chills, fever, body aches, etc. — is either staying the same or getting worse. All in all, just be aware of your body and how you're feeling.

As aforementioned, the Pfizer COVID-19 vaccine consists of two separate shots that are administered 21 days apart. So what exactly happens to the body after the second Pfizer jab? We've got the answers you're looking for. The normal side effects that we've previously discussed can return after the second dose of the vaccine, and a decent number of people reported feeling worse than they did after the first shot. But don't be alarmed — your body's heightened reaction to the second dose is a good sign. 

Dr. Debra Powell, who serves as Tower Health's chief of infectious diseases in Pennsylvania, told Healthline that the common side effects people may experience after the second vaccine are signs that the jab has "triggered a response by your immune system" — basically, these side effects are a way you can tell the vaccine's doing its job. "When you feel sick or have a fever, that's largely your body responding," Dr. Powell said. "It's usually a very short-term thing and much better than getting COVID and being sick for 2 weeks or in the hospital." Dr. Powell explained that the first COVID vaccine "teaches" the body how to respond to the virus, while the second is a boost to the system. The two shots are 90 percent efficient in protecting vaccinated people against the virus, as noted by The Washington Post. 

So what is so bad about the second dose of the Pfizer COVID-19 vaccine and why have so many people heard that it's far worse than the first? Here's the breakdown. As noted by The New York Times, people who got the second Pfizer jab described their symptoms as flu-like. One person said that the symptoms "flattened" them, and another said that they were "useless for two days." People who signed up for the vaccine study were even told to schedule time off work so they could recover from the second shot if need be. 

So let's break it down by numbers, so it's not super overwhelming. About 29 percent of people said they felt fatigued after their first Pfizer shot, whereas 50 percent of people said they felt fatigued after the second. Reports of muscle aches went from 17 percent after the first Pfizer shot to 42 percent, and rates of body chills and fevers went from 7 percent to 26 percent. So is there a decent chance you could feel a bit under the weather after the second Pfizer shot? Yes, but it's also 100 percent better than getting the coronavirus.

So let's talk about something that can't be controlled but is still very annoying. As noted by The New York Times, women have reportedly been experiencing a more serious reaction to the Pfizer COVID-19 vaccine than men, and that's just flat out frustrating. But there are reasons, so we'll break it down for you. 

After the first 13.7 million COVID vaccines were administered in the United States, an analysis found that common side effects were more prevalent in women. The analysis also found that almost only women experienced rare serious reactions to the vaccine like going into anaphylactic shock. 

Unfortunately, this is pretty standard. Women have often reported more significant side effects to a variety of other vaccines than their male counterparts, so it looks like the COVID vaccine is nothing if not consistent. So why the unfair symptoms? Women, obviously, have estrogen which can "stimulate" the immune system's response. Testosterone, on the other hand, has the ability to "blunt" the immune system. Because being a woman isn't hard enough.

We've spent a lot of time talking about side effects, what can happen to the body, and what to expect after getting the Pfizer COVID-19 vaccine. But what if you get the jab and experience no side effects? Did it work? Should you be concerned? Your answers are: yes, it worked, and no, you shouldn't be worried. 

As noted by The New York Times, side effects and the potential risks of the vaccine typically get attention, but they really shouldn't. During the trial of the Pfizer vaccine, one in four patients reported having no side effects at all. That's a 25 percent chance that you won't feel the slightest bit under the weather, and given how detrimental the coronavirus can be to your body, those odds sound pretty good. 

Dr. Paul Offit, who sits on the Food and Drug Administration's vaccine advisory panel, told The Times that those who don't experience any symptoms after their vaccine should not be worried, especially given the over 90 percent success rate of the shot. Unfortunately, not a ton is known about why some people get side effects and others don't.

There have been questions circulating around the Pfizer COVID-19 vaccine and people who have previously had and recovered from the coronavirus, so here's what you need to know. As noted by The New York Times, both research and testimonies from people previously diagnosed with the coronavirus showed that some who had the virus reacted more severely to the vaccine than those who never got it. 

Research and experiences from those who have received the vaccine also showed that those who reacted more severely to the first jab may have had the coronavirus at some point, even if they hadn't been aware of the virus in their body. So if you had the coronavirus or you tested positive for the coronavirus antibodies, you should prepare yourself to possibly have a stronger reaction to the shot. 

The Times recommended possibly taking a couple of days off work, not only for your own health and well-being, but also for the peace of mind of your colleagues (that's if you go into work and aren't working from home). Plus, a couple days in bed is always a good call if you're feeling under the weather.

There's been information floating around about the side effects that come with the different vaccines, so we're going to lay out the confirmed information for you. When it comes to the Pfizer COVID-19 vaccine, about 18 percent of people experience headaches after the first dose, while 43 percent have headaches after the second dose, according to the Centers for Disease Control. For comparison, about 20 percent of people who receive the Moderna vaccine also develop headaches, and about 39 percent of those who get the Johnson & Johnson vaccine developed headaches (via the FDA). 

If fatigue is more your concern, here are the numbers. According to studies, after the first Pfizer vaccine, around 47 percent of people experienced fatigue, which jumped to 59 percent after the second shot. For those who had the first Moderna shot, 39 percent reported fatigue, which jumped to 68 percent after the second. For those who took the single-dose Johnson & Johnson vaccine, about 38 percent said they felt fatigued. 

As far as body chills are concerned, almost 6 percent of people who got the first shot and 31 percent of those who received the second shot of Pfizer reported chills. About 9 percent of people who received the first Moderna vaccine experienced chills, while 48 percent of people had chills after the second dose. A small percentage of Johnson & Johnson vaccine recipients also reported the side effect.