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5 Different Types Of Vaccines

    In this 5 Different Types of Vaccines post we have briefly explained about Vaccines, characteristics, and different types of vaccines. Read on to learn more about different types of vaccines!!

    Vaccine

    Vaccination for all to provide protection against a disease, it must expose an individual to pathogen-specific antigens that will stimulate a protective adaptive immune response. By its very nature, this entails some risk. As with any pharmaceutical drug, vaccines have the potential to cause adverse effects.

    However, the ideal vaccine causes no severe adverse effects and poses no risk of contracting the disease that it is intended to prevent. Different types of vaccines have been developed with these goals in mind.

    Different Types Of Vaccines

    Vaccine

    5 Different Types of Vaccines

    Live Attenuated Vaccine

    Live attenuated vaccines from different types of vaccines expose an individual to a weakened strain of a pathogen with the goal of establishing a subclinical infection that will activate the adaptive immune defenses.

    Pathogens are attenuated to decrease their virulence using methods such as genetic manipulation or long-term culturing in an unnatural host or environment.

    By establishing an active infection, live attenuated vaccines stimulate a more comprehensive immune response than some other types of vaccines. Live attenuated vaccines activate the both cellular and humoral immunity and stimulate the development of memory for long-lasting immunity.

    In some cases, vaccination of one individual with a live attenuated pathogen can even lead to natural transmission of the attenuated pathogen to other individuals. This can cause the other individuals to also develop an active, subclinical infection that activates their adaptive immune defenses.

    Disadvantages associated with live attenuated vaccines include the challenges associated with long-term storage and transport as well as the potential for a patient to develop signs and symptoms of disease during the active infection. There is also a risk of the attenuated pathogen reverting back to full virulence.

    Examples: Chickenpox, German measles, measles, mumps, tuberculosis, typhoid fever, yellow fever

    Inactivated Vaccine

    Inactivated vaccines from different types of vaccines contain whole pathogens that have been killed or inactivated with heat, chemicals, or radiation. For inactivated vaccines to be effective, the inactivation process must not affect the structure of key antigens on the pathogen.

    Because the pathogen is killed or inactive, inactivated vaccines do not produce an active infection, and the resulting immune response is weaker and less comprehensive than that provoked by a live attenuated vaccine.

    Typically the response involves only humoral immunity, and the pathogen cannot be transmitted to other individuals. In addition, inactivated vaccines usually require higher doses and multiple boosters, possibly causing inflammatory reactions at the site of injection.

    Despite these disadvantages, inactivated vaccines do have the advantages of long-term storage stability and ease of transport. Also, there is no risk of causing severe active infections. However, inactivated vaccines are not without their side effects. Examples: Cholera, hepatitis A, influenza, plague, rabies

    Subunit Vaccine

    Whereas live attenuated and inactive vaccines from different types of vaccines expose an individual to a weakened or dead pathogen, subunit vaccines only expose the patient to the key antigens of a pathogen not whole cells or viruses.

    Subunit vaccines can be produced either by chemically degrading a pathogen and isolating its key antigens or by producing the antigens through genetic engineering.

    Because these vaccines contain only the essential antigens of a pathogen, the risk of side effects is relatively low. Example: Anthrax, hepatitis B, influenza, meningitis, papillomavirus, pneumococcal pneumonia, whooping cough

    Toxoid Vaccine

    Like subunit vaccines, toxoid vaccines from different types of vaccines do not introduce a whole pathogen to the patient; they contain inactivated bacterial toxins, called toxoids.

    Toxoid vaccines are used to prevent diseases in which bacterial toxins play an important role in pathogenesis. These vaccines activate humoral immunity that neutralizes the toxins. Examples: Botulism, diphtheria, pertussis, tetanus.

    Conjugate Vaccine

    A conjugate vaccine from different types of vaccines is a type of subunit vaccine that consists of a protein conjugated to a capsule polysaccharide.

    Conjugate vaccines have been developed to enhance the efficacy of subunit vaccines against pathogens that have protective polysaccharide capsules that help them evade phagocytosis, causing invasive infections that can lead to meningitis and other serious conditions.

    The subunit vaccines against these pathogens introduce T-independent capsular polysaccharide antigens that result in the production of antibodies that can opsonize the capsule and thus combat the infection; however, children under the age of two years do not respond effectively to these vaccines.

    Children do respond effectively when vaccinated with the conjugate vaccine, in which a protein with T-dependent antigens is conjugated to the capsule polysaccharide.

    The conjugated protein-polysaccharide antigen stimulates production of antibodies against both the protein and the capsule polysaccharide. Examples: Meningitis (Haemophilus influenzae, Streptococcus pneumoniae, Neisseria meningitides).

    Further Readings

    Reference

    1. https://www.historyofvaccines.org/content/articles/different-types-vaccines
    2. https://www.hhs.gov/immunization/basics/types/index.html
    3. https://www.immune.org.nz/vaccines/vaccine-development/types-vaccines