Uncategorized Vaccines

COVID-19 Vaccine Side Effects

I’ve seen common trends with mRNA side effects. Learn what to expect so you can make educated decisions about vaccines.

As I’ve seen more people get vaccinated with the COVID19 mRNA vaccines (both Pfizer and Moderna) I’ve seen common trends with side effects. I think it’s important that we know what to expect so we can make educated decisions about vaccines.

I don’t want people to fear these vaccines – the illness has a much greater risk than the vaccine for most people. Understanding the science of how these vaccines are made may help allay some of your fears. If you missed my post on how they’re made, check it out here.

Everyone who is vaccinated is invited to participate in a monitoring program called V-Safe. This data collection will help us all learn more over time!

What about the serious allergic reactions?

Yes, there have been a few people among the many thousands who have gotten the vaccine and had serious allergic reactions, but this pales in comparison to the MANY who have been very sick from COVID19 infection. Some have prolonged complications after even mild COVID19 infections.

Remember that not all who are very sick are hospitalized or die, so these are often underrecognized and not shared in all the hospitalization rates and death counts.

Most of the people who have had serious allergic reactions have a known history of serious allergic reactions, but this does not mean that people with known allergies should not get the vaccine.

If you have a history of anaphylaxis, talk to your physician about the risks and benefits. Bring your epinephrine to the vaccine appointment and let the staff know your risks and that you’ve spoken with your physician and are prepared.

Pfizer vs Moderna?

Side effects for both Pfizer and Moderna brands seem to be similar. They can start immediately or a few hours later.

In general the reactions to the 2nd dose seem to be more significant than to the 1st dose. People who have had COVID infection also seem to react more. This shows that the immune system recognizes a past exposure (to the vaccine or infection) and is DOING ITS JOB. This is a good thing in my book!

What I’m hearing reported – remember not everyone has these symptoms:
  • Fever
  • Arm soreness
  • Muscle aches
  • Back ache
  • Joint pains
  • Fatigue
  • Nausea/vomiting
  • Headache
  • Facial numbness/tingling
  • Dizziness
  • Fainting
  • Swollen glands in the armpit and over the collarbone
  • Delayed redness and swelling in the arm of the injection site, starting 7-14 days after the injection and lasting 1-7 days.
Many of these symptoms are not unique to the COVID19 vaccine.
  • Many parents recall a fussy baby or child after routine vaccines – or their own sore arm after a routine vaccine. Any vaccine can lead to aches and pains or fever that are short lived and easily managed with pain relievers. This is not a sign of infection, but a sign that your immune system is busy doing its job.
  • Teens are especially prone to fainting after vaccines or blood draws. It’s the needle, not what’s in the needle, that leads to this.

Home remedies can be used to treat most side effects:

  • ibuprofen or acetaminophen for fever/pain
  • anti-itch cream or antihistamine for itchiness
  • significant allergic reactions should be managed by medical professionals. Most of these occur within the first few minutes after the vaccine. Everyone should wait at least 15 minutes after their vaccine to monitor for serious reactions.

The best thing about the vaccines are that they are very effective!

They cannot cause infection and do not lead to the complications we see with infection, such as strokes/blood clots, heart problems, prolonged fogginess and fatigue, lung damage, kidney failure and more.

The vaccine provides IMMUNITY!

And yes, it’s still recommended to wear your mask and continue to practice safe precautions to help limit the spread of COVID19 after vaccination at this time.

As immunity rates improve these recommendations will change.

But we need more people to be vaccinated to safely lift restrictions and get back to normal!

A GREAT video!

I’m adding this video because Dr. Kimberly Manning explains the mRNA vaccines in a way that makes it easy for anyone to understand. Follow her on

Side effects we’re NOT seeing

Because there’s so much misinformation being shared about risks of these vaccines, I want to share what is NOT a side effect of these vaccines.

Infection from the vaccine

The mRNA vaccines only give instructions to make the spike protein commonly found on COVID19. There is no possibility of catching COVID19 from the vaccine.

Some people who have not had time to build full immunity with both doses of vaccine have been exposed to COVID19 infection and gotten sick, but that’s due to the timing of exposure, not a failure of the vaccine or the vaccine causing the infection.

Viral shedding from the vaccine

Again, there is no virus in the mRNA vaccines, so it is not possible to shed the infection from the vaccine.

It is possible to spread the infection if you’ve been exposed, even after your vaccine, so it is important to continue to practice safety recommendations, such as wearing a mask and avoiding crowds.

Changes to our DNA

No one is going to grow a tail or have altered DNA after an mRNA vaccine.

It’s just not possible for mRNA to affect our DNA. DNA is in the cell nucleus and the mRNA cannot enter the nucleus.

mRNA only gives instructions to make a protein, then it is broken down by the body. It can’t do anything to your DNA.


I’ll leave this to a great video by a board certified OB-GYN. Follow Dr Danielle Jones on Twitter for more great information related to women’s health!


There is no reason anyone would need to microchip us through a vaccine. It’s already possible to track people with their phones and smart watches, why would anyone pay to develop this expensive technology? How exactly would that work?

There is no microchip in the vaccine.

Bell’s Palsy

Bell’s Palsy is a temporary facial paralysis that can occur after viral infections. While it did occur in mRNA study participants, it was actually at a lower rate among those who got the COVID19 mRNA vaccine compared to the general population.

It is likely that any Bell’s Palsy following the vaccine was coincidental.

Addendum: 3/4/21

Delayed Large Local Reactions to mRNA-1273 Vaccine against SARS-CoV-2 (NEJM report of delayed arm reactions)

For more myth busting:

mRNA vaccine myths – anti-vax lies about COVID-19 vaccines (Skeptical Raptor)

The COVID-19 Vaccine: Myths vs. Facts (MU Health)

COVID-19 vaccine myths debunked (Mayo Clinic)

COVID-19 Vaccine Misinformation and the Anti-Vaccine Movement

Related posts:

COVID-19 Vaccines

What to do after COVID-19 Exposure

By DrStuppy

I am a pediatrician and mother of two teens. I have a passion for sharing health related information.

7 replies on “COVID-19 Vaccine Side Effects”

Thank you for sharing this! I am curious if there’s any information on those that have had serious allergic reactions. Do we know if there is any correlation to their allergic reactions to the vaccine and allergies that they have to other medicines?

From what I understand, most people who have had serious allergic reactions have a history of severe allergic reactions, but not necessarily to any one medication. At this time everyone who is vaccinated should wait 15 minutes minimum after the vaccine to watch for an allergic reaction. Those who are at increased risk should wait longer. The risk of a serious allergic reaction is miniscule compared to the risk of COVID19 infection complications. If you have a history of allergic reactions, talk with your physician and if you’re getting the vaccine, tell the person administering it so they can be prepared.

You’re welcome! I was intrigued when someone asked me about their red arm. I thought it was too late for a vaccine reaction or cellulitis from the shot, but it seems to be a common side effect. I’m learning so much since the pandemic started!

I just got the delayed arm rash about 8 days after my vaccination. This article helped me feel better about it. Thank you.

I’m glad it helped! I think it’s easy to worry about infection or allergic reaction with the redness, but since so many have had it and it goes away, that makes it a lot less scary!

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