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Biology LibreTexts

12.1B: Vaccination

  • Page ID
    11818
  • Vaccination is a proven way to prevent and even eradicate widespread outbreaks of life-threatening infectious diseases.

    Learning Objectives

    • Describe how active immunity to diseases can be acquired by natural exposure or by vaccination

    Key Points

    • Immunization is the administration of antigenic solution, usually orally or via injection, to protect against infectious bacterial and viral diseases.
    • Vaccinations are usually given at specific ages and dates as per the recommended schedule provided by The Center for Disease Control.
    • Vaccines stimulate the body to produce antibodies without manifesting clinical signs and symptoms of the disease in immunocompetent hosts.

    Key Terms

    • toxoids: bacterial toxins whose toxicity has been inactivated or suppressed.
    • immunity: the state of being insusceptible to a specific thing.
    • immunocompetent: Having a functioning immune system.

    Active immunity to diseases can be acquired by natural exposure (in response to actually contracting an infectious disease ) or it may be acquired intentionally, via the administration of an antigen, commonly known as vaccination.

    image
    Figure: Vaccination:: a child receiving an oral polio vaccine.

    Vaccination has proven to be an effective way to stimulate the human body’s natural ability to produce antibodies, without contracting the disease and suffering any of its effects. This is also known as ‘acquired’ resistance.

    The various antigenic materials used in these vaccinations (or immunization) may be of animal or plant origin. Some vaccinations are composed of live suspensions of weak or attenuated cells or viruses, deadened cells or viruses, or extracted bacterial products such as the toxoids used to immunize against diphtheria and tetanus.

    Vaccinations are developed to stimulate the body’s production of antibodies without the manifestation of clinical signs and symptoms of the disease in immunocompetent hosts. Moreover, active immunization should cause permanent antigenic memory or lifelong immunity.

    Vaccinations are usually given at specific ages and dates according to the recommended schedule provided by The Center for Disease Control. Sometimes booster vaccinations are needed to provide additional immunity in certain individuals and in certain cases.

    Once your immune system has been trained to resist a disease, you are said to be immune to it. Before vaccines were developed, the only way to acquire immunity to a disease was to actually get it and, with luck, survive it. Even today, the risk of contracting some of these infectious diseases, like measles and chicken pox, can have devastating, long-term complications, like blindness.

    Despite some of the various controversies surrounding vaccines over the years, the tiny proportion of risk is far outweighed by the numerous benefits. Certain infectious diseases, such as Smallpox, have been completely eradicated. Global mass vaccination drives have met with enormous success in reducing the incidence of many diseases.

    Another consideration is that the newer vaccination programs also protect older age groups. By these vaccinated children not contracting these diseases, their parents, grandparents, friends and relatives (not vaccinated against these diseases themselves) will also be protected.