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Vaccination is an important means of preventing infectious diseases and protecting population health. This principle of activating the immune system to strengthen defences against pathogens is implemented through various vaccines. In this article, we’ll look at the basic principles of immunisation and the classification of vaccines according to their manufacturing methods.

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Basic principles of vaccination

Immunity and the immune system

Overview of the immune system

• The immune system is an important biodefence mechanism that distinguishes harmful pathogens, eliminates them, and protects our body.
• Every minute of every day, our bodies come into contact with different types of pathogens, including bacteria, viruses, and fungi.
• As these external elements try to invade our internal environment, the immune system detects and eliminates them to provide continuous protection for our body.

Key components

• The immune system is made up of many different components.
• The most important of these are antibodies and specific cells. Antibodies are a key component of the immune system and are involved in the identification and elimination of pathogens.
• Specific cells are responsible for regulating the immune response, identifying and eliminating pathogens.

How the immune system works

• The immune system works through a variety of pathways and mechanisms. When you are first exposed to a pathogen, your immune system learns and forms a memory.
• This allows the immune system to respond quickly and effectively to eliminate the pathogen when the same pathogen enters the body again.
• This immune memory is one of the most important characteristics of the immune system and is closely related to how vaccination works.

An important biodefence system

• The immune system is an important biodefence system that plays a key role in keeping our bodies alive and healthy.
• The immune system protects us in the battle against pathogens and keeps our internal environment stable.

Passive immunity

Passive immunity overview

• Passive immunity is a way to activate the immune system without direct exposure to a pathogen.
• This method is primarily achieved by using serum (the liquid part of the blood that contains the antibodies needed to acquire immunity).
• It is characterised by the transfer of antibodies acquired from another individual or animal.

How passive immunity works

• Passive immunity can also be achieved through natural means.
• For example, breastfeeding, where a young child absorbs antibodies from its mother and gains immunity, is a form of passive immunity.
• Another way is to artificially produce antibodies to create a serum, which is then injected into an individual to boost their immunity.

Uses of passive immunity

• Passive immunity is often used in situations where there is a high risk of exposure to a virus or toxin.
• For example, gaining immunity by injecting influenza antibodies to prevent the flu.
• Passive immunisation works well in situations where the immune system needs to respond quickly.

Limitations of passive immunisation

• Passive immunisation only provides immunity to specific pathogens and therefore does not provide complete protection against a wide range of pathogens.
• In addition, the antibodies acquired can fade over time, making it difficult to provide lasting protection.

Relationship between passive immunity and vaccination

• Vaccination is primarily an application of the principles of passive immunity.
• Vaccination uses a weakened pathogen or part of a pathogen to induce immunity, and individuals acquire immunity without being exposed to the disease.
• This can help prevent illness and prevent the spread of infectious diseases.

Effective strategies to boost immunity without pathogen exposure

• Passive immunity, the transfer of antibodies to acquire immunity without direct exposure to a pathogen, is an important strategy for strengthening the immune system.
• It is used as one of the principles behind vaccination and plays a large role in protecting individuals from a variety of infectious diseases.

Being exposed to or recovering from a disease

Immune response after disease exposure

• The immune system plays an important role after the human body has been exposed to a disease or has undergone an illness.
• In these situations, the immune system goes through the process of creating antibodies and memory cells against the pathogen.
• This ensures that if you are subsequently exposed to the same pathogen again, your immune response will be faster and stronger than before.

Immune memory and boosting

• Immune memory plays an important role during re-exposure to a pathogen.
• When you are first exposed to a pathogen, your immune system learns about it and forms memory cells.
• These memory cells are responsible for triggering a fast and powerful immune response when the same pathogen is introduced again.
• This can prevent or reduce illness.

Recovery and immunity

• The immune system also plays an important role during the recovery period after an illness.
• After an illness, the immune system continues to protect the individual by producing antibodies and memory cells against the pathogen.
• This allows re-exposure to that pathogen to elicit a rapid and effective immune response, reducing the severity of the disease.

Relevance to vaccination

• The principles involved in immune memory are one of the key concepts behind immunisation.
• Immunisation creates an immune memory even in the absence of exposure to a pathogen, triggering a fast and effective immune response when an individual encounters the same pathogen.
• In this way, immunisation serves to protect individuals against a wide range of infectious diseases.

Disease exposure and immune response

• After the body is exposed to a disease or undergoes an illness, the immune system produces antibodies and memory cells to form an immune memory.
• This allows for a quick and strong immune response to the same pathogen, a process that is closely linked to the principle of immunisation.

Classification of Vaccines by Manufacturing Method

Classification of vaccines

• Vaccines used for immunization are broadly divided into live attenuated and inactivated vaccines based on their manufacturing method.
• Each vaccine has its own unique characteristics and plays an important role in preventing disease and preventing its spread.

Live attenuated vaccines

Overview of live attenuated vaccines

• Live attenuated vaccines are vaccines that are derived from wild pathogens that actually cause infections in humans and have been attenuated in the laboratory.
• By weakening the pathogen, these vaccines are able to multiply in the body and trigger an immune response, but they do not cause actual disease.

Mechanisms of action and benefits

• Attenuated live vaccines stimulate the immune system’s antibodies and memory cells as a weakened form of the pathogen multiplies in the body.
• This process provides antigens similar to the pathogen while avoiding the risk of the actual disease.
• Because of this mechanism of action, attenuated live vaccines can build strong, long-lasting immunity.

Typical attenuated live vaccines

• Attenuated live vaccines are used to protect against a wide range of infectious diseases.
• For example, measles, yellow fever, chickenpox, and shingles vaccines are examples of attenuated live vaccines.
• These vaccines attenuate the respective pathogens, which renders them non-pathogenic but capable of triggering an immune response.

How are they administered orally?

• Attenuated live attenuated vaccines are primarily administered orally.
• This offers convenience to patients.
• Oral administration eliminates the need for injections and allows immunity to be built in a much safer way compared to actual infection with the pathogen.

Cautions and limitations

• Attenuated live vaccines are not available in all cases.
• Some attenuated live attenuated vaccines can activate pathogens and cause disease if immunity is not sufficiently developed.
• Therefore, these vaccines must be administered as directed by a physician, taking into account the patient’s condition and immunity, before use.
• Attenuated live vaccines are made by weakening the actual pathogen, so they stimulate the immune system but do not cause actual disease.
• They are administered orally and are used to prevent a variety of infectious diseases, including measles, yellow fever, chickenpox, and shingles.
• However, it is important to consider the precautions and limitations of its use and to consult a doctor before administering it.

 Inactivated Vaccines

Overview of inactivated vaccines

• Inactivated vaccines are vaccines that are injected after the pathogen is killed by treating it with heat or chemicals.
• This treatment makes the pathogen unable to multiply, but it still retains its structure and antigens.
• This is based on the principle of exposing the immune system to the actual pathogen’s form and antigens, but without causing actual disease.

Why are they given by injection?

• Inactivated vaccines are primarily administered by injection, which is one of their main features.
• When a vaccine is given by injection, it prevents the pathogen from being active or transmitted in the patient’s body because it does not multiply.
• This allows it to trigger an immune response while minimizing the risk of infection.

Typical inactivated vaccines

• Inactivated vaccines are used to protect against a variety of infectious diseases.
• For example, vaccines such as polio, hepatitis A, and pneumococcal fall into this category.
• These vaccines inactivate the respective pathogens, leaving the antigens intact, and are administered by injection to trigger an immune response.

Difficulty maintaining permanent immunity

• Some inactivated vaccines have difficulty maintaining permanent immunity from a single dose.
• This is because the dead form of the pathogen makes it difficult for the immune response to be sustained.
• Therefore, these vaccines may require a booster dose, and it’s important to get them regularly as directed by your doctor.

Inactivated vaccines for safe protection

• Inactivated vaccines are vaccines that are given by injection after the pathogen has been treated to make it dead, exposing the antigens of the pathogen but not causing the actual disease.
• They are used to prevent a variety of infectious diseases, including polio, hepatitis A, and pneumococcal.
• Some vaccines may not provide permanent immunity from a single dose, so it’s important to get a booster shot as directed by your doctor.

Polysaccharide vaccines

Overview of polysaccharide vaccines

• Polysaccharide vaccines are vaccines that utilize the polysaccharides that make up the bacterial coat.
• These vaccines aim to trigger an immune response by utilizing antigens from the bacterial polysaccharide coat.
• Polysaccharide vaccines are primarily used as cellular fractionated vaccines, where the polysaccharide antigens of the bacteria are used alone to elicit a T-cell-independent immune response.

T-cell-independent immune responses

• Polysaccharide vaccines are characterized by triggering a non-T-cell-dependent immune response.
• A T-cell-independent immune response refers to the enhancement of an immune response primarily by antibodies.
• This is mainly induced by the bacterial coat polysaccharide antigens, and this immune response contributes to the prevention of infection by bacteria.

Mainly used in children and immature immune systems

• Polysaccharide vaccines are primarily used in children and individuals with immature immune systems.
• This is because these individuals may not be able to mount a strong immune response to a pathogen.
• Polysaccharide vaccines can help protect these individuals from infections caused by bacteria.

Typical polysaccharide vaccines

• Polysaccharide vaccines are used to protect against a variety of infectious diseases.
• For example, vaccines against Haemophilus influenzae type b, pneumococcus, and meningococcus fall into this category.
• These vaccines are primarily administered using polysaccharide antigens from bacteria, which trigger a T-cell-independent immune response to prevent infection.

Boosting immune defense with polysaccharide vaccines

• Polysaccharide vaccines are manufactured using the polysaccharides that make up the bacterial coat, which trigger a T-cell-independent immune response to boost immune defense through antibodies.
• They are primarily used in children and individuals with immature immune systems and are used to prevent infectious diseases such as Haemophilus influenzae type b, pneumococcus, and meningococcus.

Recombinant vaccines (Recombinant vaccines)

Introduction to recombinant vaccines

• Recombinant vaccines are vaccines made using antigens produced using genetic recombination technology.
• These vaccines typically produce antigens in yeast cells or other host cells and utilize them to manufacture the vaccine.
• Recombinant vaccines are manufactured through innovative approaches developed with advances in modern life science technology.

How recombinant vaccines work

• Recombinant vaccines isolate the antigenic genes of a specific pathogen and transfer them to another host cell.
• This host cell then produces the corresponding antigen, which is then utilized to manufacture the vaccine.
• This technology is used to make hepatitis B vaccine/Human papillomavirus vaccine, typhoid live vaccine, live attenuated influenza vaccine, etc.

Features of recombinant vaccines

• Recombinant vaccines produce antigens in yeast cells or other host cells, which can increase safety, unlike traditional vaccines that use the pathogen itself.
• By selectively using only antigens that trigger an immune response to a specific pathogen, it is possible to induce an effective immune response while minimizing side effects.

Typical recombinant vaccines

• Recombinant vaccines are used to prevent a number of infectious diseases.
• For example, the hepatitis B vaccine/human papillomavirus vaccine is used to prevent human papillomavirus infection, and the typhoid live vaccine was developed to prevent typhoid infection.
• Attenuated influenza live vaccines are utilized to boost immunity against influenza.

Innovative vaccines utilizing gene recombination technology

• Recombinant vaccines are innovative vaccines that utilize gene recombination technology to produce and use antigens.
• These vaccines use yeast cells or other host cells to trigger a safe and effective immune response and are utilized to prevent several infectious diseases.

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Frequently asked questions and answers

Q1: Why are immunizations important?

A: Immunizations play a key role in preventing infectious diseases and stopping the spread of disease. They play a big role in protecting population health because they activate the immune system to strengthen defenses against pathogens.

Q2: What is the difference between attenuated and inactivated live vaccines?

A: Attenuated live vaccines use attenuated pathogens that multiply in the body and trigger an immune response, but do not cause disease. Inactivated vaccines use dead pathogens and trigger an immune response.

Q3: In what cases are polysaccharide vaccines used?

A: Polysaccharide vaccines are made using the polysaccharides that make up the bacterial coat and are often used in children and individuals with immature immune systems.

Q4: How are recombinant vaccines made?

A: Recombinant vaccines utilize genetic recombination technology to produce and use antigens in yeast cells or other host cells. This ensures both safety and an effective immune response.

Q5: Why can I still get sick after getting a vaccine?

A: Vaccines usually boost immunity against a given pathogen, but they may not guarantee complete protection. Some vaccines may not be permanent and may have limited effectiveness against mutated pathogens.

Bottom line

Immunization is a key strategy for preventing infectious diseases and protecting population health. Vaccines are classified according to different manufacturing methods, each with its own unique characteristics. Attenuated live, inactivated, polysaccharide, and recombinant vaccines are all used as effective means of immunization and are selectively utilized based on their characteristics and intended use. It is important to remember that immunization is an important tool not only for individual health, but also for societal health.

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