Validated Covid-19 Vaccine Side Effects

validated covid-19 side effects

Like any other vaccine against different viral infections, various side effects are also linked with the Covid-19 vaccine. Some of the various Covid-19 Vaccine Side Effects are similar to that of other vaccines. Fortunately, most of these symptoms are mild and don’t last long for more than one to three days [1].

Validated Covid-19 Vaccine Side Effects

Common side effects include sore arms, tiredness, headache, muscle aches, and high body temperature. Again, however, there are some severe side effects, but they are uncommon. Understanding the side effects of the Covid-19 vaccine before taking a dose of it is essential. In the U.S, all the people getting vaccinated against Covid-19 observed very mild side effects. Still, the prevalence of severe side effects is much less.

In this article, you will learn about the validated side effects of the three well-known vaccines for Covid 19.

Validated Covid-19 Vaccine Side Effects

AstraZeneca Covid Vaccine

The University of Oxford and AstraZeneca developed the AstraZeneca Covid Vaccine. This vaccine works by transferring the information of the spike protein of SARS-CoV-2 into host body cells and is considered an mRNA vaccine. In the host body, a unique protein is formed (antibodies), enhancing the immunity that helps recognize this spike protein. Once it gets recognized, the immune response will be initiated. This will also provide future immunity against this strain of the coronavirus.

Validated Covid-19 Vaccine Side Effects - 18/05/2024

This kind of vaccine has been used in other conditions, including flu and middle east respiratory syndrome (MERS). Initial clinical trials showed that this vaccine could prevent almost 70.4% of Covid-19 cases. This vaccine is injected into the upper arm in two doses, and there must be a gap of 4-12 weeks between them. Pfizer or Moderna vaccines are used as booster doses in the U.K [2].

Two severe and non-treatable side effects of this vaccine are discussed here.

Thrombosis with thrombocytopenia syndrome (TTS)

Along with some familiar and mild side effects, a sporadic blood-clotting condition is also associated with this vaccine, called thrombosis with thrombocytopenia syndrome (TTS). In 4 to 42 days after getting vaccinated with the AstraZeneca vaccine, the symptoms of TTS appeared.

In this side effect of the covid-19 vaccine, blood clots that don’t occur mostly with other vaccination will be formed along with low platelets count. Common symptoms of this side effect include a headache lasting more than 48 hours after vaccination. Additionally, the pain worsens on lying down, with nausea and vomiting, blurred vision, speaking and breathing difficulty, drowsiness, seizures, chest pain, leg swelling, stomach pain, and small blood spots will be formed under the skin [3].

Validated Covid-19 Vaccine Side Effects - 18/05/2024

TTS is more likely to occur after your first dose of the AstraZeneca Vaccine. However, people who already got their first dose without any side effects can have their second dose of this vaccine. If a person experiences TTS after their first dose, they should take a second dose of a different vaccine to avoid the AstraZeneca Vaccine’s adverse effects.

Guillain Barré Syndrome

Another side effect of the AstraZeneca Vaccine is Guillain Barré syndrome (GBS). It is a severe neurological condition that appears after the first dose of AstraZeneca.

Guillain-Barre syndrome is a unique disorder in which the body’s immune response damages your nerves. The first neurological manifestation of this disease is a tingling sensation in the hands and feet, which corresponds to sensory loss.

Later with the progression of the nerve damage, the patient presents with a unique paralysis that begins in the lower limbs and then involves the upper body structures. But, in a few patients, initial symptoms of muscle paralysis can start in the hands and face.

Once the paralysis reaches the thorax, it can cause paralysis of breathing muscles. Breathing paralysis is the most severe symptom of this complication, leading to respiratory failure or death [4]. However, early and effective treatment can halt the progression of nerve damage and significantly increase the chances of a patient’s survival.

This GBS syndrome is reported as a rarely occurring side effect after vaccination. However, its relationship with the vaccine has yet to be confirmed; further studies are still required on this aspect. WHO works closely with healthcare workers to review the rare reports linked with GBS for safety concerns and to manage potential risks associated with this syndrome [5].

The Pfizer BioNTech

The Pfizer BioNTech Vaccine has been approved as a vaccine against Covid-19 in individuals above the age of 12 years or more. It is a monovalent vaccine administered in two doses[6]. The main constituents of this vaccine include nucleoside-modified messenger RNA of SARS-CoV-2 that codes for viral spike glycoprotein. Along with this, sucrose and different lipids, including cholesterol, are also present. In addition, several salts are present, like potassium chloride (KCl), sodium chloride (NaCl), and sodium phosphate dehydrate [7].

The Pfizer Vaccine is an RNA-based vaccine often associated with some adverse events. Therefore, it’s essential to report the clinically significant adverse effects, even if it’s unclear whether it is because of that vaccine or not [8].


One side effect of the Pfizer Vaccine is Myocarditis, an inflammation of the heart muscles. Some of the symptoms associated with myocarditis include inflammation caused by the body’s immune system and severe allergic reaction, causing severe chest pain, shortness of breath, and a rapid heartbeat.

Myocarditis is rarely reported as a side effect of the Pfizer vaccine. Still, some of its cases have been reported in adolescents and among male adults within several days after vaccination. Symptoms of this side effect most commonly appear after the second dose or within a week of vaccination. Patients who received care and medication soon after this side effect may feel better quickly. Those who have been diagnosed with myocarditis must have to consult their cardiologists about the suitable exercises that they need to do [9].

Moderna Vaccine

The Moderna Covid-19 vaccine is an mRNA-based vaccine that is also a two-shot vaccination. So if you feel side effects after getting the first injection, you may have had covid-19 before. Still, if you feel side effects after getting the second dose, then it means that you have never had covid-19 before [10].

This vaccine has similar side effects as the Pfizer Covid-19 Vaccine. In addition, it can also cause side effects like myocarditis that must be resolved as soon as possible. However, studies reported that Moderna Vaccine is safe to be used by pregnant women during their pregnancy and can also be taken by breastfeeding mothers [11].

What are the general Covid 19 vaccine side effects?

Some common mild side effects associated with getting the first or second dose of the Covid-19 vaccine include pain, swelling, fever, tiredness, headache, muscle pain, chills, pain in joints, vomiting, swollen lymph nodes, and feeling unwell. Most of these symptoms don’t need any treatment. They go away on their own in a few days.

Similarly, mild headaches and muscle aches don’t need emergency care after vaccination and can be resolved independently.

Validated Covid-19 Vaccine Side Effects - 18/05/2024

Due to side effects in specific age groups, some vaccines are prescribed differently. For example, Janssen/Johnson & Johnson vaccine is recommended to be taken at 18 and older.

What can you do about these side effects?

If you experience pain after getting vaccinated, you should talk to your doctor about some medicines that can help relieve pain and discomfort. To reduce arm aches and discomfort, one should have to apply a clean, wet washcloth over the specific area and have to do arm exercises.

Contact your doctor or healthcare provider if the redness at the injection site increases after 24 hours. Try to take over-the-counter drugs as they can help treat fever and chills and relieve headaches. Before being vaccinated, you don’t have to take these drugs. The study reported that some pain-relieving medicines could interact with the vaccine’s immune response. Still, more study is required to clarify whether taking medications before vaccination can affect their efficacy or not [12].

What is the role of family members?

Family plays an essential role in treating a person who has suffered from the disease and with side effects after vaccination. One should have to counsel the patient, give them moral support, and check the medicines that a patient must take to relieve their symptoms. As people are terrified of this pandemic disease so, it’s very crucial to tell them the person that doesn’t trust false myths and try to make them feel better.

When to see a doctor or healthcare provider?

One should have to visit the doctor or healthcare provider if they notice any swelling or signs in their body after getting the covid-19 vaccine dose. Suppose their symptoms aren’t relieved 24 hours after getting vaccinated. In that case, they have to talk to their doctor about their condition to provide some medications that will help a person in reducing their symptoms. If, after vaccination, one experiences serious allergic reactions and severe side effects like heart pounding and chest pain, they must rush to the hospital in an emergency to get early treatment and get better quickly.


1.      The Oxford/AstraZeneca (ChAdOx1-S [recombinant] vaccine) COVID-19 vaccine: what you need to know [Internet]. [cited 2022 Oct 25]. Available from:

2.      What are the vaccines’ side effects? – Mayo Clinic [Internet]. [cited 2022 Oct 25]. Available from:

3.      Australia H. Thrombosis with thrombocytopenia syndrome (TTS) [Internet]. 2021 [cited 2022 Oct 25]. Available from:

4.      UCL. Rise in Guillain-Barré syndrome following AstraZeneca vaccine [Internet]. UCL Queen Square Institute of Neurology. 2022 [cited 2022 Oct 25]. Available from:

5.      McKean N, Chircop C. Guillain-Barré syndrome after COVID-19 vaccination. BMJ case reports [Internet]. 2021 Jul 30 [cited 2022 Oct 25];14(7). Available from:

6.      Commissioner O of the. Pfizer-BioNTech COVID-19 Vaccines. FDA [Internet]. 2022 Aug 31 [cited 2022 Oct 25]; Available from:

7.      Regalado A. What are the ingredients of Pfizer’s covid-19 vaccine? [Internet]. MIT Technology Review. 2020 [cited 2022 Oct 25]. Available from:

8.      CDC. Pfizer-BioNTech COVID-19 Vaccine Information | CDC [Internet]. 2020 [cited 2022 Oct 25]. Available from:

9.      CDC. COVID-19 Vaccination [Internet]. Centers for Disease Control and Prevention. 2020 [cited 2022 Oct 25]. Available from:

10.  Maragakis L, Kelen G. COVID Vaccine Side Effects [Internet]. 2021 [cited 2022 Oct 25]. Available from:

11.  World Health Organization. The Moderna COVID-19 (mRNA-1273) vaccine: what you need to know [Internet]. 2021 [cited 2022 Oct 25]. Available from:

12.  COVID-19 Vaccine Side Effects: Why They Happen and How to Treat Them | Memorial Sloan Kettering Cancer Center [Internet]. [cited 2022 Oct 25]. Available from:

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Dr. Fatima Tariq

Hi there. This is Dr. Fatima Tariq. I did my MBBS from one of the prestigious medical schools in my country. My years in medical college have helped me to polish my writing skills to perfection. I have been working as a freelancer for 4 years now. My writing is very concise, easy-to-read, and well-researched. My biggest priority is conveying the information in an informative and professional way.

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