Vaccine side effects

  • by VaccineHealthCenter

For every normal human being with good health, the body will have natural protection against disease-causing pathogens. This kind of protection is called natural immunity, the body’s inborn ability to fight the disease-causing agents. When someone often gets sick, the natural immunity against some specific diseases, including life-threatening ones, will be reduced.  Additionally, the body might sometimes find it hard to fight severe infections that the body’s immunity has not come into contact with. In such cases, the immunity is compromised. However, the process of vaccination can help boost the body’s immunity and prepare the immune system to fight pathogens.


A vaccine refers to the biological preparation that provides active acquired immunity to a particular infectious disease. A vaccine typically contains an agent that strikes a resemblance to a disease-causing microorganism and is often made from attenuated or killed forms of the microbe, its toxins, or one of its surface proteins. The safe, simple, effective way of protecting a target population from a disease before contact with that disease is called vaccination. The process of vaccination uses the body's natural defense system to develop pathogen immunity. The agents of the pathogens used in the vaccines are weakened or killed, but they still possess the characteristics of that pathogen. The vaccine thus stimulates the type B cells to produce antibodies just like it would with the actual exposure to the pathogen. Although vaccines are generally meant for man's good, sometimes they harm the recipients. How does this happen? It is through the side effects.

What are vaccine side effects?

A vaccine is a form of medication that involves giving injections, oral drugs, or spraying the nose to offer the body protection against some infection(s). Just like any other form of medication, vaccines may have side effects on whoever gets them. Side effects refer to the adverse reactions that surface after taking medication (or any substance that can alter body function). Sometimes the side effects are known as the contraindications or adverse effects. They are also described as the unwanted symptoms of a given medical treatment.

Side effects associated with vaccine intake

When one receives a vaccine, he does so primarily to protect himself. However, the following are side effects related to vaccine intake;

  • Hospitalization
  • Fatality (death)
  • A life-threatening condition (like anaphylaxis)
  • Disability (may occur when the body does not welcome a certain component of the vaccine)
  • Congenital anomaly
  • Organ malfunction in extreme cases

These are long-term effects, some even having permanent damages. Short-term side effects include nausea, vomiting, diarrhea, slurred speech, and tiredness.

What causes vaccine side effects?

There is no single vaccine that is dispatched to the public for consumption without clinical stages and trials. The clinical stages of vaccine development consist of about five steps, among the steps being a safety test. That's when the regulatory bodies such as the Food and Drug Administration (FDA), European Union (EU), and Centre for Disease Control and prevention (CDC) test for the vaccine's safety. However, passing safety taste doesn't mean the vaccine has no adverse effects, it means that the vaccine itself is safe for life. Consequently, it may still give rise to adverse reactions. These could be caused by;
A substance or molecule in the vaccine; various people will exhibit various (or same) side effects upon taking a vaccine. This is because the vaccine could be having a specific component that triggers allergic reactions, leading to side effect development. For instance, most Covid-19 vaccines have a component called polyethylene glycol (PEG), which is thought to be causing anaphylaxis.
Drug abuse; while some vaccines might have the potential to cause side effects, others might not have that potential and only develop the contraindications upon abuse. Such cases of abuse may mean taking the subsequent shot of vaccine before the stipulated time ends. For instance, most Covid-19 vaccines have a period of 28days between a vaccine shot and the next. If for whatever reason, a person lies to the vaccine provider about the date for the first shot and takes the second shot before the expected time, the side effects could be triggered.

When to call a doctor

Part of your duty as a doctor involves enlightening the patients. You might have to advise them on the emergency signs of a vaccine that could necessitate calling your doctor or health care provider. Let’s take the example of Covid-19. There is a life-threatening adverse reaction called anaphylaxis. Anaphylaxis refers to a life-threatening reaction of the body to allergens (including venoms animal bites, dust, pollen, or some food like peanuts and tree nuts). Anaphylaxis usually starts with mild signs of weakness, tiredness, itchy skin, or difficulty in breathing. However, if the signs persist, causing wheezing, blue lips, convulsions, and some more serious effects. When such happens and the signs keep escalating, there might be a need to call the person's doctor or go to the hospital for the side effect management.


While a vaccine offers the body relative protection against infection before contact with the disease, some adverse conditions might still develop. The side effects vary from mild to severe and include breathing problems, slurred speech, dizziness, tiredness. Under extreme cases, disabilities and organ malfunctions may occur.