What You Need To Know If You Are Taking the COVID-19 Vaccine

Stephanie Tardieu, MD and Marie-Ange Tardieu, MD  

If you are wondering whether you should get the vaccine, you are in good company. According to the Pew Research Center, the first week of December 2020, roughly 46% of Americans were on the fence and said that they might get the COVID-19 vaccine, but only after others got the vaccine and more information becomes available.

The first COVID-19 vaccine was administered to a nurse in New York City on the morning of December 14th, 2020. Since then, both the Pfizer-BioNTech and Moderna COVID-19 vaccines have been administered across the US, primarily to healthcare providers and frontline workers. So far, according to the CDC, about 4.6 million Americans have received one of these vaccines, as the rest of the United States and the rest of the world watch in anticipation either waiting for their turn to get the vaccine or wondering if they should get it once it becomes available to them.

The biggest questions on most people’s minds are: Is the vaccine safe? and will it work? Our goal in this article is to provide you with the most up-to-date information currently available about these vaccines to empower you to make an informed decision about whether you should get the vaccine or not.

COVID-19: The Pandemic

A little over one year ago, in December of 2019, a pneumonia outbreak of unknown cause began in Wuhan, China. The virus causing this epidemic was soon identified and called SARS-Cov-2, and the disease that it caused was called COVID-19. It is highly contagious and not long after its discovery, the rest of the world soon followed with growing epidemics of their own.

In March of 2020, the World Health Organization (WHO) declared COVID-19 to be a global pandemic. To this day, the world has seen over 82 million cases with 1.8 million deaths from the COVID-19 pandemic. In the United States, where we are currently experiencing our most significant surge of the virus since the pandemic started, over 20 million people have been infected and over 350,000 Americans have died from the virus.

Why does the world need a COVID-19 vaccine?

The facts speak for themselves.

The COVID-19 numbers continue to rise rapidly and exponentially in all groups of people but especially in high-risk groups such as the elderly and those with underlying medical conditions. The elderly and people with high-risk underlying medical conditions are more likely to suffer from severe COVID-19 disease and have a much greater risk of ICU admission, intubation, and death. These high-risk conditions include diabetes, obesity, and high blood pressure of which 10%, 42% and 45% of Americans suffer from, respectively.

Moreover, there is no way to know how COVID-19 will affect you. There are large numbers of previously young and healthy people who develop severe COVID-19 and die from its complications. There are also large numbers of people who have COVID-19 and have no symptoms at all but spread it to their family members and communities leading to others they know to become seriously ill and, in many cases, die of the disease.

Because of how infectious and severe this disease can be, and the astronomical number of people affected in the US and the world, the fastest, safest, and most effective medical intervention to reduce the spread of the virus and curtail the death rate from COVID-19 is to use a vaccine to protect the population.

What is the COVID-19 vaccine and how does it work?

How do other vaccines work? We usually think of a vaccine as being an injection of live germs that have been attenuated or weakened. These are called live attenuated vaccines. They trigger a controlled immune response that trains the body to fight a particular germ whenever such germ is encountered later in the life of the subject. For instance, if you took the MMR vaccine, this means that you received an injection of live weakened Measles, mumps, and rubella viruses. MMR is therefore a live attenuated vaccine.

There are also inactivated vaccines, which use killed germs to trigger the cells of your body to build immunity. When you get a flu shot, it is an injection of killed or inactivated influenza virus. The flu shot is therefore an inactivated vaccine. Polio and rabies vaccines are also inactivated vaccines. Those vaccines are less effective; they offer less protection and therefore require boosters to maintain immunity.

The Covid-19 vaccines currently being in use in the US are neither live attenuated nor inactivated vaccines. These two COVID-19 vaccines, one from Pfizer and the other from Moderna, use a molecule called messenger RNA (mRNA) to confer immunity. Messenger RNA (mRNA) is a molecule that carries the instructions necessary for your cells to make different proteins. It is not DNA and cannot alter your DNA.

The mRNA, which is used in the two COVID-19 vaccines in the US, carries instructions into the cells of your body to make a COVID-19 protein without the parts of the virus that make you sick. When your body is exposed to this mRNA, you will then be able to produce antibodies against the COVID-19 protein coded for by the mRNA vaccine, without you becoming sick with the disease.

In other words, the COVID-19 vaccine does not give you the COVID-19 disease, but it allows your body to mount an immune response to the virus by exposing you to a nontoxic part of the virus that is in the vaccine. This way, if your body becomes exposed to the COVID-19 virus in the future, you will be able to mount an immune response and produce antibodies to help your body fight the virus.

Does the COVID-19 vaccine work?

Both COVID-19 vaccines that are currently available in the US have been shown to be highly effective at preventing the COVID-19 disease based on the studies that are currently available. Two doses of these vaccines administered 3 weeks (Pfizer) or 4 weeks (Moderna) apart are required to achieve (95%) efficacy after the second dose.

You will not achieve 95% protection from COVID-19 immediately after the second dose of the vaccine. It will take 1 to 2 weeks after the second dose for you to be considered fully vaccinated and protected.

If you do test positive for COVID-19 after this time frame, based on current data and data available from other vaccines, experts believe that the COVID-19 vaccines could prevent you from developing severe COVID-19 disease, thus avoiding life-threatening complications.

Should I still continue to socially distance and wear a mask if I get the COVID-19 vaccine?

Given the limited information available on how well the vaccine will work under real life conditions, and the lack of knowledge on how long the immunity from the vaccine will last, if you get vaccinated, you should continue to follow the CDC guidelines to protect yourself and others from getting COVID-19. These include:

  • Covering your nose and mouth with a mask
  • Avoiding crowds and indoor gatherings
  • Wash your hands with soap and water or hand sanitizer frequently
  • Avoid touching your face
  • Continue social distancing and stay at least 6 feet apart from others
  • Follow the CDC travel guidelines
  • Follow your workplace and school guidelines
  • Follow the quarantine guidelines after exposure to someone with COVID-19

Together, getting the vaccine and following these guidelines will offer you and others the best protection from contracting COVID-19 and offers the world the best chance of ending the pandemic and the spread of the virus as soon as possible.

Can I still get COVID-19 even if I get the vaccine?

The data available at this time to answer this question is limited and the duration of protection against COVID-19 from the vaccines is currently unknown.

No vaccine is 100% effective. However, both COVID-19 vaccines that are currently available in the US have been shown to be highly effective at preventing the COVID-19 disease based on the research studies that are currently available. Two doses of the vaccines administered 3 weeks (Pfizer) or 4 weeks (Moderna) apart are required to achieve (95%) efficacy after the second dose.

There has been anecdotal evidence of health care providers becoming sick with COVID-19 after the first dose of the vaccine. This is not unexpected and does not mean that the vaccine did not work. You will not achieve 95% protection from COVID-19 immediately after the 2nd dose of the vaccine. It will take on average 1 to 2 weeks following the second dose for you to be considered fully vaccinated and protected.

If you do test positive for COVID-19 after completion of your vaccine, based on the current studies and data from other vaccines, experts believe that the COVID-19 vaccines could prevent you from developing severe COVID-19 disease thus avoiding life-threatening complications.

Do I need to get the vaccine if I have already had COVID-19?

Currently, it is unknown how long immunity from being sick with COVID-19 lasts. Current data suggest that immunity obtained from having been sick with COVID-19 may last 3 to 4 months.

There is also no data currently available regarding how long the vaccines will protect you against COVID-19 and whether immunity from the vaccines is the same as immunity obtained from having been sick with COVID-19. Therefore, it is recommended that you get the vaccine even if you have been sick with COVID-19.

Are there any side effects associated with the COVID-19 vaccine?

The most common side effects associated with the COVID-19 vaccines are mild to moderate. They can occur after the first or second dose, usually within the first 3 days after the vaccine and lasting 1 to 2 days. Side effects observed in the available studies were less common in those over the age of 55 and symptoms were usually worse after the second dose.

The most common side effects reported from the phase 3 clinical trials so far are:

  • Pain, redness or swelling where the shot was given (80%)
  • Fatigue (60%)
  • Headache (50%)
  • Muscle pain (10-20%)
  • Chills (10-20%)
  • Joint pain (10-20%)
  • Fever (14%)

You should be monitored for 15 minutes after your injection to monitor for side effects. If you develop any of these side effects, please notify your health care provider for further guidance.

Some of these side effects are like the signs and symptoms of COVID-19. If you’ve received the vaccine and have been exposed to COVID-19 or you develop COVID-19 symptoms that last longer than 2 days following the vaccine, please call your health care provider, self-isolate, and get tested.

Rare and more serious side effects have also been reported after obtaining the vaccine, however, they have been reported as very rare. These include severe allergic reactions (i.e. anaphylaxis) and temporary paralysis of the face (i.e. Bell’s palsy). 

Who can get the COVID-19 vaccine?

  • The COVID-19 vaccine has received FDA emergency use authorization (EUA) for people who are 16 years old or older
  • Anyone currently or recently infected with COVID-19 should wait 90 days after their recovery to get the vaccine
  • Anyone who does not have a contraindication to obtaining the vaccine (please see below)

Who should not get the COVID-19 vaccine?

These are the contraindications to the vaccines as listed by Pfizer, Moderna, the FDA and the CDC.

You should not receive either of the COVID-19 vaccines if you have a history of any of the following:

  • A confirmed severe or non-severe allergic reaction to a previous dose of either one of the COVID-19 vaccines
  • A confirmed severe allergic reaction (i.e. hives, facial swelling (angioedema), difficulty breathing or anaphylaxis) to any component of either COVID-19 vaccine
    • This includes polyethylene glycol (PEG) or polysorbate, a known allergen commonly found in medicines and in household goods and cosmetics. Allergy to PEG is extremely rare and may be unknown. People with an undiagnosed PEG or polysorbate allergy may have a history of unexplained anaphylaxis or anaphylaxis to multiple classes of drugs.
    • Components of the Pfizer COVID-19 vaccine also include:
      1.  mRNA
      2. Lipids ((4-hydroxybutyl)azanediyl)bis(hexane-6,1-diyl)bis(2-hexyldecanoate), 2 [(polyethylene glycol)-2000]-N,N-ditetradecylacetamide, 1,2-distearoyl-sn-glycero-3-phosphocholine, and cholesterol)
      3. Potassium chloride
      4. Potassium phosphate
      5. Sodium chloride
      6. Sodium phosphate dihydrate
      7. Sucrose
    • Components of the Moderna COVID-19 vaccine also include:
      1. mRNA
      2. Lipids (SM-102, polyethylene glycol [PEG] 2000 dimyristoyl glycerol [DMG], cholesterol, and 1,2-distearoyl-sn-glycero-3-phosphocholine [DSPC])
      3. Tromethamine hydrochloride
      4. Acetic acid
      5. Sodium acetate
      6. Sucrose
    • Neither the Pfizer nor the Moderna COVID-19 vaccine contains any preservatives
    • Neither the Pfizer nor the Moderna COVID-19 vaccine vial stoppers are made with latex

Can I get the COVID-19 vaccine if I have a history of allergies?

If you have a history of any allergic reaction to any vaccine or injectable medication, the CDC recommends that you consult your health care provider to determine if it is safe for you to get the COVID-19 vaccine. We recommend the same and preferably consultation with a specialist in Allergy and Immunology to be evaluated for PEG and polysorbate allergy.

If you have a history of a severe allergic reaction (i.e. hives, angioedema (facial swelling), difficulty breathing or anaphylaxis) not related to vaccines or injectable medications, such as food or environmental allergies, the CDC recommends that you can still get the vaccine if you have no other contraindications. We recommend consultation with your health care provider if you have any questions or concerns about this recommendation. 

If you have a history of severe allergy of any kind, you should be monitored for 30 minutes after you get the vaccine in case you develop an allergic reaction and require urgent medical treatment. Persons with no history of allergy should be monitored for 15 minutes after vaccination or as needed.

Special populations and the COVID-19 vaccine:

o   Persons who are immunocompromised, on immunosuppression therapy, or have HIV may be at increased risk for severe COVID-19 disease. There is currently no data available to establish the safety and efficacy of the vaccine in this group. At this time, the CDC recommends that you can still receive the COVID-19 vaccine if you have no contraindications.

If you are immunocompromised, you should know that you may not mount a full immune response to the vaccine and may have a higher risk of contracting COVID-19 after your vaccination. We recommend consulting your health care provider to discuss your specific case further before obtaining the vaccine.

  Pregnant persons and breast-feeding mothers should know that there are currently no data on the safety and efficacy of the COVID-19 vaccines in pregnant or breastfeeding women.  Based on current knowledge, however, experts believe that mRNA vaccines are unlikely to pose a risk to the pregnant person, developing baby, or breastfeeding baby because mRNA vaccines are not live viruses.

The American College of Obstetricians and Gynecologists (ACOG) currently recommends that COVID-19 vaccines should not be withheld from pregnant persons who meet the criteria for vaccination and that the decision to vaccinate should be made based on the pregnant person’s wishes, their individual risk of contracting COVID-19 and other factors in their history. If you are pregnant or breastfeeding, talk to your health care provider about the risks and benefits of getting the COVID-19 vaccine.

  Persons who have dermal filler injections should know that a small number of cases of facial swelling have been reported in people with dermal fillers after getting the COVID-19 vaccine. So far, all these facial swelling reactions have been mild and responded quickly to oral steroids or oral antihistamines.

Currently, the Aesthetic Society recommends that having a history of dermal fillers should not prevent someone from getting the COVID-19 vaccine because the benefits of being protected from COVID-19 outweigh the risk of facial swelling observed in this small group. If you have any questions about dermal fillers and getting the COVID-19 vaccine, we recommend consulting your plastic surgeon or skin care specialist to discuss your specific case.

Last, but not least…

For you to achieve maximum protection from the COVID-19 vaccine, your body needs to be able to mount a strong immune response. We recommend that if you are considering taking the vaccine, in addition to continued social distancing and good hygiene practices, that you optimize your intake of essential vitamins and nutrients to boost your immune system. Vitamin C, vitamin D, Quercetin, Zinc, and Vitamin B complex, have all been cited as good immune boosters. Our complete recommended immune-boosting vitamin regimen is listed in our What Should You Do if You Test Positive for COVID-19? blog article and YouTube video. If you are going to follow this protocol, we recommend you speak with your own physician to make sure that it is safe for you to take these vitamins with your medical history or pre-existing medical conditions.

We hope this helps! 


We have no relevant financial or nonfinancial relationships in the products described, reviewed, and discussed in this article.

As always, this information is not meant to treat you. It is only intended to be educational. The information in this article regarding the COVID-19 vaccines is the most up-to-date information available as of January 5th, 2021. Please understand that this information is rapidly evolving and may change as the year moves forward.

If you have any real-time questions regarding obtaining the vaccine or concerns regarding your own health and well-being, please consult, and speak with your health care provider.


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