How do vaccines work?

Vaccines protect people and communities against deadly diseases. They have completely eradicated smallpox, and almost eliminated other diseases like polio. The body has many ways of defending itself against pathogens (disease-causing organisms). Skin, mucus, and cilia (microscopic hairs that move debris away from the lungs) all work as physical barriers to prevent pathogens from entering the body in the first place. When a pathogen does infect the body, our body’s defenses, called the immune system, are triggered and the pathogen is attacked and destroyed or overcome.

Vaccines have saved millions of lives in the last 100 years. But many countries are reluctant to get vaccinated, and the trend is growing.

How do vaccines work and why are they important? In this video, I introduce vaccination, herd immunity and other key concepts.

What is vaccination?

Vaccination is the safest way to protect your child against infectious disease. Once your child has been vaccinated, they should have the ability to fight off the disease if they come into contact with it. They will have a level of protection, or immunity, against the disease.​

Photo by Anna Shvets from Pexels

The body’s natural response-

A pathogen is a bacterium, virus, parasite, or fungus that can cause disease within the body. Each pathogen is made up of several subparts, usually unique to that specific pathogen and the disease it causes. The subpart of a pathogen that causes the formation of antibodies is called an antigen. The antibodies produced in response to the pathogen’s antigen are an important part of the immune system. You can consider antibodies as the soldiers in your body’s defense system. Each antibody, or soldier, in our system, is trained to recognize one specific antigen. We have thousands of different antibodies in our bodies. When the human body is exposed to an antigen for the first time, it takes time for the immune system to respond and produce antibodies specific to that antigen.

In the meantime, the person is susceptible to becoming ill.

Once the antigen-specific antibodies are produced, they work with the rest of the immune system to destroy the pathogen and stop the disease. Antibodies to one pathogen generally don’t protect against another pathogen except when two pathogens are very similar to each other, like cousins. Once the body produces antibodies in its primary response to an antigen, it also creates antibody-producing memory cells, which remain alive even after the pathogen is defeated by the antibodies. If the body is exposed to the same pathogen more than once, the antibody response is much faster and more effective than the first time around because the memory cells are at the ready to pump out antibodies against that antigen.

Photo from Who.int

This means that if the person is exposed to the dangerous pathogen in the future, their immune system will be able to respond immediately, protecting against disease. A pathogen is a bacterium, virus, parasite or fungus that can cause disease within the body. Each pathogen is made up of several subparts, usually unique to that specific pathogen and the disease it causes. The subpart of a pathogen that causes the formation of antibodies is called an antigen. The antibodies produced in response to the pathogen’s antigen are an important part of the immune system. You can consider antibodies as the soldiers in your body’s defense system. Each antibody, or soldier, in our system is trained to recognize one specific antigen. We have thousands of different antibodies in our bodies. When the human body is exposed to an antigen for the first time, it takes time for the immune system to respond and produce antibodies specific to that antigen.

How vaccines help-

Vaccines contain weakened or inactive parts of a particular organism (antigen) that triggers an immune response within the body. Newer vaccines contain the blueprint for producing antigens rather than the antigen itself. Regardless of whether the vaccine is made up of the antigen itself or the blueprint so that the body will produce the antigen, this weakened version will not cause the disease in the person receiving the vaccine, but it will prompt their immune system to respond much as it would have on its first reaction to the actual pathogen.

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Some vaccines require multiple doses, given weeks or months apart. This is sometimes needed to allow for the production of long-lived antibodies and the development of memory cells. In this way, the body is trained to fight the specific disease-causing organism, building up a memory of the pathogen so as to rapidly fight it if and when exposed in the future.

Herd immunity-

When someone is vaccinated, they are very likely to be protected against the targeted disease. But not everyone can be vaccinated. People with underlying health conditions that weaken their immune systems (such as cancer or HIV) or who have severe allergies to some vaccine components may not be able to get vaccinated with certain vaccines. These people can still be protected if they live in and amongst others who are vaccinated. When a lot of people in a community are vaccinated the pathogen has a hard time circulating because most of the people it encounters are immune. So the more that others are vaccinated, the less likely people who are unable to be protected by vaccines are at risk of even being exposed to harmful pathogens. This is called herd immunity.

Photo by Artem Podrez from Pexels

This is especially important for those people who not only can’t be vaccinated but may be more susceptible to the diseases we vaccinate against. No single vaccine provides 100% protection, and herd immunity does not provide full protection to those who cannot safely be vaccinated. But with herd immunity, these people will have substantial protection, thanks to those around them being vaccinated.

Vaccinating not only protects yourself but also protects those in the community who are unable to be vaccinated. If you are able to, get vaccinated.

How effective is vaccination?

Vaccination is extremely effective with most childhood vaccines effective in 85% to 95% of children who receive them.1 It is considered one of our greatest global health achievements and is estimated to save 2–3 million lives a year.2 Thanks to vaccines, life-threatening diseases that used to be common in young children in the UK, such as diphtheria, whooping cough and polio, are now relatively rare. Looking at the history of vaccine-preventable disease, there is a huge drop in the number of cases of a disease following the introduction of a vaccine against it. If smallpox had not been eradicated, it would cause 5 million deaths worldwide a year!3 Through vaccination, some diseases have even been eradicated completely, for example, smallpox.

How was the vaccine discovered?

The world was a much more dangerous place before the vaccine was created. Millions of people would die from all the diseases that can be easily cured now. The idea of ​​vaccination was created in China. In the 10th century, there was a Chinese medical system called ‘Variation’ where the tissue was taken from the body of a sick patient and implanted in the body of a healthy person.

Photo by Gustavo Fring from Pexels

Eight centuries later, the British physician Edward Jenner noticed that cowherds who succumbed to the disease were infected with the smallpox of cows, but that the deadly smallpox infection was rare among them.

Chickenpox was one of the most deadly infectious diseases at that time. Thirty percent of those who contracted the disease would die. And those who survived were either blinded or had severe scars on their faces.

In 1796, Dr. Jenner performed an experiment on an eight-year-old boy named James Phipps.

He collects pus from cow dung, which is not a deadly disease and injects it into the boy’s body. A few days later, James Phipps’ body showed signs of spring.

Photo from Reuters

After the disease was cured, he injected the smallpox virus into the boy’s body. But it turned out that James Phipps had no spring. The germs of the cow spring have saved him from the more deadly cocoon spring.

Dr. The results of Jenner’s experiment were published in 1896. The world became familiar with the term vaccine for the first time. The word ‘vaccine’ comes from the Latin word ‘vaxa’ which means cow.

Where is the success of the vaccine?

Vaccine use has greatly reduced the number of deaths over the past century. The measles vaccine has been used since the 1960s. But before that, the disease killed 2.6 million people every year. According to the World Health Organization, the number of deaths from measles vaccines decreased by 70% between 2000 and 2016.

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Sheikh Riad

Sheikh Riad

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