Our Readers Report Their Side Effects to the COVID-19 Vaccine

COVID vaccine side effects

MedShadow was the first to launch its COVID-19 Vaccine Side Effect Tracker, even before any COVID-19 vaccines were authorized by the Food and Drug Administration (FDA). Its goal is to report on the adverse effects in clinical trials, help our readers make informed decisions and know what to expect when they get their shots. Experts said early on that some of the side effects may be severe enough that patients will want to stay home from work after receiving the vaccine. 

Our vaccine side effect tracker has amassed more than 800 comments, a handful of which have discussed unusual reactions, such as blurred vision and heart palpitations.

Heart and vision symptoms weren’t reported in the clinical trials and haven’t yet been the focus of any investigations published by the Centers for Disease Control and Prevention (CDC). So, MedShadow is exploring those symptoms.

A series of case studies from Switzerland reported that nine out of the first 12,349 people vaccinated there experienced a rise in blood pressure after receiving their first dose of the Pfizer or the Moderna vaccine. Some also had headaches, chest pains, sweating and anxiety. All but one of the patients reported having a history of well-controlled hypertension. Six patients required emergency treatment or monitoring, and all recovered.

One online survey reported that four out of 803 healthcare workers who replied and had received the Pfizer vaccine experienced blurred vision. Another 35 reported heart palpitations. The same research group found similar results for patients who received the Moderna vaccine. The survey had several limitations, including the fact that nearly 90% of those respondents  were women. Patients submitted their responses anonymously, and neither the researchers nor other healthcare providers evaluated their symptoms. Nor did the researchers take into account any preexisting conditions or collect data on the timing of symptoms. Lastly, the study only included participants who reported at least one symptom. Patients who experienced no adverse effects were excluded from the analyses.

We cannot firmly conclude that any of the symptoms reported in this study or in the comments from our tracker were or were not COVID vaccine side effects.

Racing Heart

On Feb. 6, 2021, Matt L. described having immediate heart palpitations in the comment section of MedShadow’s side effect tracker. “Within 2-3 minutes of vaccination I experienced rapid heart palpitations, which lasted a couple minutes, I thought I might die. Was it a stress reaction? I have no history of adverse reactions to vaccines. My heart rate remained elevated about 20 beats above normal for the 30 minute observation period and was still elevated and irregular that evening. I was unable to sleep. The next day my heart was back to near normal, but I had to take off work a couple days due to feeling crappy. I reported it on VAERS,” he writes.

Others, like Nick, who submitted this comment on April 8, 2021, have told of palpitations that started later and lasted longer. “I received my first dose on March 2nd and my second dose on March 30th of the Moderna vaccine. Both times about 7 days into each dose I started noticing heart palpitations. I do not have any heart disease, except controlled high blood pressure. After the first dose, they started and were happening often, and was concerning – then they stopped after 5 days right before my scheduled second shot. Now after my second dose, they have started again a week after the dose. Not sure if they are related to the vaccine, but good to see others are experiencing this symptom too. I will see my PCP next week, Hopefully, the palpitations will stop as they did after the first shot.”

Blurred Vision

Several others mentioned blurred vision in the days following the shot. TrudyD who writes, “Had first Pfizer shot on 3/12/2021 at 1:30pm. Woke at 6 AM next day with blurred vision in right eye. Lasted 12 hours. Am headed to ophthalmologist this week to discuss. Not many reporting blurred vision to date. I reported to cdc. I think I will wait 4-6 weeks and evaluate reports before proceeding. Event was definitely outcome of shot. I take no meds and have no conditions.”

On April 1, 2021, Sean writes, “My Moderna 2nd shot was 3/15/21. Right eye has serious blocked vision to left side, just developed 3/31. Will be scheduling Ophthalmologist visit. Will followup with results.”

Two doctors involved in administering vaccines told MedShadow that they haven’t cared for any patients with vision symptoms or heart palpitations persisting into the days after the shots. “Many patients of ours have described diverse symptoms, some with an allergic flavor (hives, rashes, for example) and some with neurologic flavor (tingling, numbness, metallic taste, even personality change!).  We have not seen [heart palpitations, elevated heart rate, blurry vision or seeing spots],” Kimberly Blumenthal MD, an allergist, immunologist and drug allergy researcher at Massachusetts General Hospital, who published some of the first accounts of delayed arm pain, writes in an email.

Kartik Cherabuddi, MD, an infectious disease expert at the University of Florida also hadn’t noticed these lingering symptoms in his patients, but added that if the symptoms emerged almost immediately after vaccination, “that would be expected with a vasovagal presyncope/syncope; [Fainting or feeling like you’re going to faint] and the heart palpitations can be seen as part of an allergic response as well.”

What is Syncope?

Syncope is a medical term for fainting, and presyncope describes the sensations that can suggest you may faint, even if you don’t end up losing consciousness, or feeling lightheaded. If you do faint, you’ll likely regain consciousness within a minute. There are many reasons you may have a syncopal episode. They include dehydration, stress, irregular heartbeats, exhaustion, low blood sugar or standing up too fast. A syncopal episode can be a symptom of heart disease or even a side effect of drugs like diuretics, calcium antagonists, ACE inhibitors, nitrates, antipsychotics, antihistamines, levodopa, opioids and alcohol.

If you are otherwise healthy, syncope and presyncope can still be caused by situational triggers, like prolonged standing, anxiety or the sight of blood. The symptoms of presyncope include:

  • Nausea
  • Vision disturbances
  • Lightheadedness
  • Sweating
  • Rapid heartbeat
  • Weakness
  • Shakiness
  • Changes in body temperature (feeling hot or cold)
  • Vertigo

What to Do

Syncope can be scary, but it is rarely a life-threatening experience. People generally recover from it in mere minutes to hours.

If you do faint, do not stand up right away when you regain consciousness, as this can cause you to faint again. The National Institutes of Health recommend that you remain lying down for at least 10 to 15 minutes and then get up slowly. If you feel signs of presyncope, it’s best to sit or lie down so that you’ll be safe if you’re likely to fall. You can also lower your head between your knees to encourage blood flow to your brain.

If you experience syncope regularly, see your doctor. He or she can conduct blood tests and order an image of your heart to rule out underlying causes. Depending on the results , your healthcare provider may suggest a change in diet, biofeedback, elevating your head while you sleep or even surgical treatments, such as implanting a pacemaker.

 [Editor’s note: We do not verify the reports we receive in comments, nor does MedShadow’s comment section serve as an official means to report side effects to agencies monitoring vaccine safety. If you experience adverse effects, be sure to report them to VAERS or to the V-SAFE app designed for COVID-19 vaccinations and see your healthcare provider. MedShadow chose to recount the comments by readers on its side tracker verbatim and not to correct them for grammar or style.] 



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1 day ago

I received my Pfizer vaccine on 5 weeks ago and immediately afterward I had a small rash in the cubital fossa (elbow crease) on both arms. Within two hours after my vaccine I experienced nausea and fatigue. On day 3 after the vaccine I started to experience heart palpitations with increased heart rate up to 170 bpm, high blood pressure, vision disturbances such as tunnel vision and eye floaters. Although these symptoms have decreased over time, I do experience episodes of recurrence. It’s a bit scary when the episodes occur and I’ve talked to a cardiologist and ophthalmologist and all… Read more »

Last edited 1 day ago by Jos
7 days ago

I just got the first moderna shot today and within the 20 minutes I sat waiting to leave Walmart I got really dizzy then it passed. Then walking out to my car I had to hold on to my husband I thought it was just wearing the mask so long and I needed fresh air but then the heart palpitations started and the dizziness that comes in waves and some shaking uncontrollably as if I was cold but I wasn’t( this only lasted about 15-20 minutes) and I was nauseated for around five hours then my ears felt like there… Read more »

7 days ago

Right after getting the Moderna second shot I experienced chills, sensitivity in the underarm area, breast sensitivity, and was very tired and weak. After about 10 to 14 days the symptoms went away and I felt like myself again. But then a week after that (three weeks after the 2nd shot) I woke up at night twice with my heart racing, and didn’t sleep the rest of the night. I also had tightness in the chest around the breastbone, nausea, less appetite, chills, cough, and was very thirsty. These symptoms persist still, and every time I go up the stairs… Read more »

Savoy IL
Savoy IL
17 days ago

Yes, a lot of people are reporting experiencing a delayed vertigo several weeks after the first shot. Possibly an autoimmune response in the inner ear during the antibody forming phase of the vaccination process. It seems most are getting completely ignored by the medical community. I has some mild to moderate dizziness two and a half weeks after the Pfizer vaccine that slowly dissipated over the next 3 weeks. I had a Meniere’s Attack in 2006 and believe my body is prone to this. It also reactivated my psoriasis on my scalp the exact same way I get a few… Read more »

Irene Au
Irene Au
18 days ago

I have also been experiencing heart palpitations since I got my first dose of Pfizer. I just got my second dose yesterday and the heart palpitations continue. At first I did not connect the dots that it was related to the vaccine, but I am sure that it is. I also experience shortness of breath from time to time. I am otherwise in top shape and am usually healthy. I hope these palpitations go away soon! Curious to know if there is any remedy or advice for me? Since this seems to be a lesson common reaction, I haven’t been… Read more »

Michael Todd
Michael Todd
19 days ago

The night of and the day after receiving the second Moderna dose my wife and I were quite sick. Chills, headaches and fevers. We expected that. What we didn’t expect was that four weeks after receiving my second dose of the Moderna Vaccine the skin on my hands started to crack and blister and the skin started to peel off. That process lasted about 2-3 weeks. Shortly after my hands “healed” it started happening to my feet. Several places the skin cracked open and bled and, like my hands, the skin started peeling off in layers. There was no pain… Read more »

Danice Hertz
Danice Hertz
19 days ago

I experienced severe paresthesias in my face, chest wall and limbs starting 30 minutes after receiving the first dose of the Pfizer covid vaccine. These symptoms have progressed over the past 18 weeks and I am being worked up for small fiber neuropathy and mast cell activation syndrome. I have a group of 75 people with similar reactions. There are clearly neurological reactions to these vaccines and they need to be publicized and studied so that we can get help.

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