Different Types of Vaccines and How They Work

Different Types of Vaccines and How They Work

Different Types of Vaccines and How They Work

Vaccines are one of the greatest medical achievements of modern times. They have helped prevent countless illnesses, saved millions of lives, and even led to the eradication of some diseases. But not all vaccines are created equal. There are different types of vaccines, and each works uniquely to protect us from infectious diseases.

In this blog post, we’ll explore the different types of vaccines, including inactivated vaccines, live attenuated vaccines, subunit, recombinant, and conjugate vaccines, mRNA vaccines, and vector vaccines. We’ll explain how each type of vaccine works, provide examples, and compare their efficacy rates, side effects, and risks. By the end of this post, you’ll better understand how vaccines work and which type of vaccine might be best suited for you and your family.

What are vaccines and vaccination:

Vaccines are biological preparations that provide immunity against infectious diseases. They contain weakened or inactive forms of the virus or bacteria that causes the disease or parts of the virus or bacteria, which stimulate the immune system to recognize and fight the pathogen.

Vaccination is a form of preventive healthcare which involves administering a vaccine to stimulate the immune system to develop immunity against a specific infectious disease. Vaccination aims to prevent infection or reduce the severity of the disease if an infection does occur.

Vaccines primed the immune system to recognize and destroy specific disease-causing pathogens. When a vaccine is administered, the immune system produces antibodies and memory cells that remember how to fight off the particular pathogen. If the person is later uncovered to be the actual pathogen, their immune system will recognize it and quickly mount a defense, preventing or reducing the severity of the infection.

Vaccination is one of the most potent ways to prevent the spread of infectious diseases and has played a crucial role in eradicating or reducing the prevalence of many deadly diseases, such as smallpox, polio, and measles. Vaccines are recommended for people of all ages, and the specific vaccination schedule will depend on factors such as age, health status, and exposure risk.

Types of Vaccines:

  1. Inactivated Vaccines

Inactivated vaccines contain viruses or bacteria that have been killed or inactivated, so they cannot cause disease. When these vaccines are injected into the body, they prompt the immune system to produce antibodies that can recognize and fight off the live virus or bacteria if the person is ever exposed. Examples of inactivated vaccines include the polio vaccine, hepatitis A vaccine, and the flu vaccine.

  • Live Attenuated Vaccines

Live attenuated vaccines contain a weakened form of the virus or bacteria that causes the disease. When these vaccines are injected into the body, they reproduce and stimulate the immune system to produce antibodies. Because the viruses or bacteria in these vaccines are weakened, they don’t cause disease in healthy people but can cause mild symptoms in people with weakened immune systems. Examples of live attenuated vaccines include the measles, mumps, and rubella (MMR) vaccine and varicella (chickenpox) vaccine.

  • Subunit, Recombinant, and Conjugate Vaccines

These vaccines contain pieces of the virus or bacteria that cause the disease rather than the whole organism. The immune system responds by producing antibodies against the fragments of the pathogen, protecting against the disease. Subunit vaccines may contain a purified protein or sugar from the pathogen, while recombinant vaccines use genetically engineered proteins to mimic the pathogen. Conjugate vaccines combine a bacterial protein with a piece of the pathogen to enhance the immune response. Examples of subunit, recombinant, and conjugate vaccines include the human papillomavirus (HPV) vaccine, the pneumococcal vaccine, and the Haemophilus influenzae type b (Hib) vaccine.

  • mRNA Vaccines

mRNA vaccines are a newer type that uses a small piece of genetic material from the virus that causes the disease. This genetic material instructs cells to produce a harmless amount of the virus, which the immune system then recognizes and produces antibodies against. Examples of mRNA vaccines include the Pfizer-BioNTech COVID-19 vaccine and the Moderna COVID-19 vaccine.

  • Vector Vaccines

Vector vaccines use a harmless virus, like a cold virus, to deliver genetic material from the virus that causes the disease into cells. The cells then produce a piece of the virus that triggers an immune response. Examples of vector vaccines include Johnson & Johnson COVID-19 and Ebola.

Each type of vaccine has unique advantages and disadvantages, and the type of vaccine used will depend on the targeted disease and the individual being vaccinated.

Comparing different types of vaccines:

Inactivated vaccines contain killed viruses or bacteria and are safe for people with debilitated immune systems but may require booster shots and may not provide long-lasting immunity. Live attenuated vaccines contain weakened viruses or bacteria and can provide long-lasting immunity with only one or two doses but are not recommended for people with weakened immune systems. Subunit, recombinant, and conjugate vaccines contain pieces of the virus or bacteria and are safe for people with weakened immune systems but may require booster shots and may not provide long-lasting immunity. mRNA vaccines use genetic material from the virus and can be developed quickly, but they need ultra-cold storage and may not be suitable for people with weakened immune systems. Vector vaccines use an attenuated virus to deliver genetic material and can provide long-lasting immunity but may not be as effective in people exposed to the vector virus.

Ultimately, the type of vaccine used will depend on the specific disease being targeted, the age of the individual, and other factors. It is important to follow the recommended vaccination schedule and consult with a healthcare professional to determine which vaccine is suitable for each individual.

Side effects and risks of vaccination:

Like any medication, vaccines can cause side effects. However, the side effects of vaccines are usually gentle and go away on their own within a few days. Some people may experience more significant side effects, but these are rare. The benefits of vaccination, including protection against potentially serious and life-threatening diseases, far outweigh the risks of side effects.

Common side effects of vaccines may include:

  • Pain or redness at the injection site
  • Fever
  • Headache
  • Fatigue
  • Muscle aches

More serious side effects are extremely rare and may include:

  • Allergic reactions, including anaphylaxis (a severe and potentially life-threatening response)
  • Guillain-Barr√© syndrome, a rare disorder that affects the nervous system
  • Thrombosis with thrombocytopenia syndrome (TTS), a rare blood clotting disorder that has been associated with some COVID-19 vaccines

It’s important to note that the risk of serious side effects from vaccines is much lower than the risk of serious complications from the diseases they protect against. For example, the risk of severe allergic reactions to vaccines is estimated to be less than one in a million doses. In contrast, the risk of complications from diseases like measles or polio can be much higher.

If you have concerns about vaccination’s risks and side effects, it’s important to talk to your healthcare provider. They can provide more information about the risks and benefits of vaccines and any specific concerns you may have. Vaccination is an important way to protect yourself and others from serious diseases, and making an informed decision about vaccination based on accurate information is important.


In conclusion, vaccines have been instrumental in controlling and eradicating many deadly diseases around the world. They have saved countless lives and greatly improved millions of people’s health and well-being. Different types of vaccines are used to protect against various diseases, and the choice of vaccine used will depend on multiple factors.

Although vaccines can cause mild side effects, the risks are far outweighed by the benefits of protection against serious and potentially life-threatening diseases. If you have any concerns about vaccination, it is important to speak to your healthcare provider for accurate information and advice.

Vaccines have played an important role in public health for many years, and their importance has become even more suitable during the COVID-19 pandemic. By staying informed about the different types of vaccines available and the associated risks and benefits, we can all play a role in protecting ourselves and our communities from serious diseases.


Q: How do vaccines work?

Vaccines work by stimulating the immune system to produce an immune response, which helps the body to recognize and fight off the disease-causing agent. This allows the body to develop immunity to the disease, which can help to prevent future infections.

Q:Are vaccines safe?

Vaccines are generally safe and thoroughly tested for safety and effectiveness before they are approved for use. The risks associated with vaccines are usually very low, and the benefits of vaccination greatly outweigh any potential risks.

Q: Do vaccines cause autism?

No, vaccines do not cause autism. Numerous scientific studies have thoroughly debunked this myth, and the overwhelming consensus among medical experts is that there is no link between vaccines and autism.

Q: What are the common side effects of vaccines?

Common side effects of vaccines include pain or redness at the injection site, fever, headache, fatigue, and muscle aches. These side effects are generally mild and go away within a few days.

Q: How long does immunity from vaccines last?

The duration of immunity from vaccines varies depending on the specific vaccine and the individual. Some vaccines provide long-lasting immunity, while others may require booster shots to maintain immunity over time.

Q: Do I still need to get vaccinated if I’ve already had the disease?   

Yes, in most cases, it is still recommended to get vaccinated, even if you have had the disease before. Vaccines can provide more reliable and long-lasting immunity than natural infection and can help to protect against future infections.

Q: Can I still get the disease even if I’ve been vaccinated?

No vaccine is 100% effective, but vaccination greatly reduces the risk of getting the disease. In some cases, even if a vaccinated person gets the disease, the symptoms are generally milder than those without vaccination.

Q: Can I get vaccinated if I have a weakened immune system?

In general, it is safe for people with weakened immune systems to receive most types of vaccines. However, some vaccines may not be appropriate for individuals with specific medical conditions. It is important to consult a healthcare provider to determine which vaccines are right for each individual.

Q: Are there any religious or philosophical exemptions to vaccination?

There may be religious or philosophical exemptions to vaccination in some places, but medical experts do not typically recommend these exemptions. Following the recommended vaccination schedule is important to protect yourself and others from serious diseases.

Categories: Vaccination
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Dr Sana Khan

I am Dr. Sana Khan, a medical student. I have experience writing, editing, and managing content for online publications. I have a strong understanding of the needs of medical websites due to my deep understanding for latest medical research and trends, and am confident that I can create high-quality content using clear and professional medical terms. My english writing skills and my knowledge as a medical student complements my career as a medical writer. Moreover I am also a dedicated individual who understands the importance of hard work as well as smart work to excell in the field. Hence i can provide accurate and quality medical communication asset to the organisation.

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