The Covid-19 Vaccine: my experience with the side effects

by The Darwinian Doctor

Today I describe getting the first and second shots of the Covid-19 vaccine, and my experience with the side effects from each shot.

This post may contain affiliate links.

TLDR: I had relatively mild side effects, worse with the second shot, that were over in 24-48 hours.

As a surgeon, I work both inside and outside of the operating room. I also take call in the hospital, see patients in clinics, and consult both in the ER and the inpatient floor.  With Covid-19 patients now flooding our hospitals, I also help take care of these patients. 

I take precautions, like wearing eye protection, a gown, and an N95 mask. With this protective equipment, infection risk is thought to be quite low. But it’s not zero.

While my children, wife, and I are at low risk of death from Covid-19, my parents are at high risk. Since we essentially live with my parents, my biggest fear is that I’ll bring home the virus, infect my parents, and cause their deaths.

So I’ve been eagerly keeping an eye on vaccine development over the past year, and I was overjoyed in December to hear that my hospital received a shipment of vaccines.

Luckily, as a front line healthcare worker I’m in the highest tier for vaccine deployment. On December 22, I got the first vaccine dose.  Specifically, I got the Pfizer-BioNTech mRNA vaccine.  

How the vaccine works

I won’t go into the detailed science behind the vaccine, but I can give a short summary of how it works. This will be pretty elementary if you’re a physician, but I hope it will help explain the concepts to our other readers.

The vaccine contains mRNA (messenger RNA). This is basically an instruction manual that tells our bodies what kind of protein to create. The mRNA in both the Pfizer-BioNTech and Moderna vaccines tells our bodies to make “spike proteins,” which is the velcro that Covid-19 uses to attach to and infect our cells.

When our bodies see the spike proteins floating around, our immune system generates antibodies. These antibodies then protect us from later infection from the SARS-CoV-2 virus that causes Covid-19.

Go to these links at the NYTimes for more details on how the Pfizer-BioNTech and Moderna vaccines work.

There’s been a lot of writing already about how this vaccine is very safe, but I thought it would be helpful if I described my personal experience with the side effects. 

Please know that my experiences might be different from your own.  

Getting the first shot

Right after getting the Covid-19 vaccine shot #1
Selfie right after getting Covid vaccine shot #1

At my hospital, they converted a big conference room into a vaccination center. On one side of the large room, there were about a dozen small tables set up with supplies and seats.  The other side of the room had a socially distanced seating area for post-vaccination observation.  There was an exciting, almost party-like atmosphere in the air.

After checking in, I filled out a survey about my allergy history and then sat down at one of the stations.  A nurse reviewed my paperwork and gathered up the precious vaccination liquid into a small syringe.  I averted my eyes and thought about gratitude to distract myself.  (I’m much more comfortable sticking needles into other people than having them pointed in my direction.)

The nurse swabbed my left shoulder with alcohol and jabbed the syringe into my deltoid.  And just like that, the precious vaccine was in my arm.  I found this shot really pain free compared to my annual flu shot, which usually burns as it goes in.  I just felt a small bit of pressure as it was over.  

After the shot, I got a bandage and my official vaccination card.  I then sat down in the waiting area for the mandatory 15 minute observation period.  I surreptitiously took a selfie while I monitored myself for signs of a severe allergic reaction, like difficulty breathing, coughing, itching, hives, or dizziness.  There were no dangerous symptoms, so I set up my second vaccination appointment and then left. 

Side effects from the Covid-19 vaccine shot #1

Early symptoms

My immediate side effect was an immense sense of gratitude.  I felt grateful that we live in an era when science is able to create vaccines to help protect us from a deadly virus.  I also felt grateful that I was able to get the vaccine at all.  

In terms of side effects, here is a chart describing my early symptoms:

At first, aside from slight shoulder soreness, I didn’t notice anything for a couple of hours.

On my drive home later that afternoon, I definitely felt more tired than usual. At dinnertime, I noticed a mild headache and a feeling like I was “coming down” with a cold. But I slept well that night with no issues.

Late symptoms

In the morning, I woke with a pretty bothersome headache. It was a throbbing headache, like one you might get after too many shots of bad tequila. I also had mild body aches.

After a cup of coffee and 400mg of ibuprofen, I felt relatively normal and was able to work a whole day of clinic. By the evening, I felt 95% back to normal. By day two, I had no noticeable side effects.

About a week later, I enjoyed the feeling of being about 50% protected from Covid-19 infection, even after just one shot..

Covid-19 vaccine shot #2

On January 8, I got the second Covid shot. The general guideline is to get it 3 weeks after the first Pfizer shot. (It’s 4 weeks apart for the Moderna vaccine.)

It was only 17 days after my first shot, but apparently the CDC says it’s OK to be four days plus or minus for the second dose.

The vaccination center atmosphere was still buzzing and positive. It was right after the lunch time rush, so there were a lot of people lounging and doing their 15 minutes of observation.

Side effects from Covid-19 vaccine shot #2

Selfie right after getting Covid vaccine shot #2
Selfie right after getting Covid vaccine shot #2

Early symptoms (shot #2)

I got the second shot around 1pm. Again, I hardly felt it go in. For the next couple of hours, I felt a little lightheaded but otherwise well. I was nervous, because I’d heard that the side effects from the second shot were much worse than from the first shot.

By dinner time, about six hours later, I had a little fatigue and a mild headache. But overall I felt pretty normal. I was worried about waking up at the 12 hour mark with chills and body aches, so I actually took a couple Motrin before I went to sleep.

Just like after the first shot, I slept through the night with no issues. 

Late symptoms (shot #2)

I woke up with a bothersome headache like after the first shot, and as I got up and stretched, I also noted some mild body aches. But I had no chills or fever to speak of.

The headache was stronger than after the first shot, and it did made it really hard to tolerate the morning shrieks and hyperactivity from my kids. Thank goodness the Dr-ess was there to corral them!

My mood brightened after I took some Motrin and my headache faded, but it never fully went away for the whole morning — it just receded into the background somewhat.

Despite the Motrin, I had fatigue throughout the morning and afternoon.  I thought of my med school friend Jmir, who ran 7 miles the day after getting his second shot. I made a half hearted attempt at doing some yardwork, but I gave up after about 15 minutes due to fatigue. 

Instead, I decided to sit in the shade and order my kids around the yard. This was much more tolerable.

Persistent symptoms

I went to bed that night with hopes that I’d feel 100% by the morning of the next day, but I was still fatigued and under the weather for the morning. Although the headache was gone, the fatigue and body aches were still both noticeable until about a full 48 hours from shot #2.

After a full two days passed from shot #2, I really felt back to normal.

That afternoon, the Dr-ess and I took the kids to the beach in Santa Monica and soaked up some winter SoCal sunlight to close out the weekend.


My experience with the Covid-19 Pfizer-BioNTech vaccine was on par with my expectations. I had pretty mild side effects after the first shot for about 24 hours. The side effects after my second shot were more noticeable and lasted a full 48 hours.

If you can arrange some time to relax after the vaccines, I’d definitely recommend it. Although I worked after my first shot (and probably could have worked after my second shot too), I was glad to have the time off.

The Covid-19 vaccine definitely caused more side effects than after my annual flu shot.

Regardless of the side effects, I can’t wait for the ~95% protection against Covid-19 infection from this life-changing vaccine. Once my immune system finishes making antibodies in about a week or so, I’ll be able to venture forth into virus-ridden Southern California with newfound confidence.


What do you think of my the experience with getting the Covid-19 vaccine and my side effects? How do they compare to your own? Did I get the science right? Please comment below and subscribe for more!


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3 years ago


Thanks for the post. I also got my second dose of the Pfizer vaccine recently. I had some mild fatigue after the second dose, but felt back to normal within 24 hours.

There is still a lot of vaccine hesitancy with my patients and I accept that a lot of factors drive this (fear, personal history, morals, experience with the health care system etc.) It’s hardly ever just about not knowing the facts. That said, I offer any and all advice I can in convincing my patients to get vaccinated.

3 years ago

I had rigors, a fever of 102 and could barely move for about a 24 period, beginning 12 hrs after my second Pfizer shot. However, I somehow managed to get AND recover from COVID between the two shots so that may have played a role. I absolutely could not have worked (or parented) yesterday but feeling much closer to normal today! Still happy and grateful to have received it!

3 years ago

Our vaccine team and employee health advised to go ahead and get it since I had pretty much recovered (and I didn’t want to have to start the series over again!). They did say I could wait 90 days if I preferred. I’m still glad I got it despite a rough post vax time!


[…] to most nations). We do such a good job of this that we’ve had a hard time controlling the Covid-19 virus because of variable enforcement of masking and social distancing regulations from state […]

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