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Vaccines and Immunization

Last updated: October 7, 2022

Immunization is a vital component of primary health care and is a basic human right. It has served to save millions of lives over the years. Vaccination is a safe, simple, and effective way of protecting against deadly diseases. It uses the body’s natural defenses to resist various infections and makes the immune system more effective. Vaccines help your immune system create antibodies when exposed to various pathogens. However, as vaccines contain only dead or weakened types of germs like bacteria and viruses, they don’t cause any disease or put you at risk of illness.

Vaccines help prevent and control infectious diseases. They help in improving global health security and will remain an effective tool against infectious diseases. Now vaccines are used to prevent about twenty lethal diseases and help people of all ages to lead longer and healthier lives. Immunization is successfully used to prevent two-three million deaths every year due to influenza, tetanus, pertussis, diphtheria, and measles.

How do vaccines work?

The immune system creates antibodies when the body is exposed to pathogens. Vaccines train the immune system to create antibodies against particular diseases. Mechanism of how vaccines work is as follows:

Our immune system has immune memory. After having one or more doses of a certain vaccine, we are protected against disease for a longer time, even a lifetime. This unique quality makes a vaccine more effective as it prevents us from falling sick before any disease occurs.

Types of vaccines

Vaccines are of several different types. Each vaccine is produced to help your immune system effectively fight against certain types of pathogens and prevent serious diseases. There are many ways to create a vaccine, but they are classified by how they generate a specific immune response against the disease-causing organism.

The following factors are taken into consideration while creating a vaccine:

These factors help scientists decide which type of vaccine they will make. There are several types of vaccines, including:

Live-attenuated vaccines

A live version of the bacteria or virus is injected through live-attenuated vaccines that cause disease in the body. Although the germ is alive, it is so weak that it does not cause any infection and cannot reproduce in the body.

These vaccines are so effective in natural infection that they help prevent and create a strong, long-lasting immune response. These vaccines are so effective that only one or two doses can provide a lifetime of protection against a germ and the illness it results in. Live vaccines are helpful to protect against mumps, measles, smallpox, chickenpox, rotavirus, rubella, and yellow fever.

Inactivated vaccines

An inactivated vaccine contains a strain of bacteria or virus that has been killed with chemicals or heat. These dead viruses or bacteria are injected into the body. Inactivated vaccines don’t provide protection as strong as live vaccines.

This means that more doses are needed to get a strong immune system against diseases. These vaccines don’t provide lifelong immunity and need several repetitions, but they may cause fewer side effects as compared to live-attenuated vaccines.

Inactivated vaccines are helpful to protect against rabies, flu (shot only), polio (shot only), and hepatitis.

Messenger RNA (mRNA) vaccines

Over the decades, researchers have been studying and working with mRNA vaccines. This technology was also used to produce some of the COVID-19 vaccines. mRNA vaccines teach human cells to make a protein that triggers an immune response.

mRNA vaccines have several additional benefits compared to other types of vaccines. These benefits include:

Subunit, recombinant, polysaccharide, and conjugate vaccines

Polysaccharide, recombinant, subunit, and conjugate vaccines use specific parts of the pathogen, like its sugar, protein, or capsid (a protecting layer around the germ)

As these vaccines use only specific parts of the pathogen, they produce a strong immune response that kills the key parts of the germ. They can be used for almost everybody who needs them, including those with weakened immune systems, and for long-term protection. One limitation of these vaccines is that you may need booster shots to get ongoing protection against diseases.

These vaccines are useful to protect against hepatitis B, whooping cough (pertussis), shingles, Hib (Haemophilus influenzae type b) disease, human papillomavirus (HPV), pneumococcal disease, and meningococcal disease.

Toxoid vaccines

Toxoid vaccines contain a toxin ( a harmful product) made by the pathogen that causes a disease. They give immunity to the parts of the pathogen that cause disease. It means that the immune response is targeted to the toxin only. Toxoid vaccines are used to protect against diphtheria, tetanus.

One may need booster shots to get ongoing protection against diseases, like many other vaccines.

Viral vector vaccines

Scientists studied viral vector vaccines for decades. The vaccines recently used against Ebola outbreaks include viral vector technology. A number of studies were focused on viral vector vaccines against other infectious diseases like flu, Zika, and HIV.

A modified version of a different virus is a vector to produce viral vector vaccines in order to deliver protection. Many different viruses have been used as vectors, including measles virus, influenza, vesicular stomatitis virus (VSV), and adenovirus, which causes the common cold. Adenovirus is a viral vector used in some COVID-19 vaccines being studied in various clinical trials.

Why should you get vaccinated?

Two major reasons to get vaccinated are to:

  1. Protect yourself
  2. Protect others around you Many people can’t get vaccinated like young babies, people with allergies, or those who are immunocompromised.

Without vaccines, people are at risk for serious illnesses and disabilities like meningitis, pneumonia, polio, tetanus, and measles. Many of these diseases are life-threatening. Over 4 million lives each year are saved merely by childhood vaccines.

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Last reviewed and updated by on Oct 7, 2022

Caitlin Goodwin, DNP, RN, CNM, is a Board Certified Nurse-Midwife, Registered Nurse, and freelance writer. She has over twelve years of experience in nursing practice.

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