How do vaccines work? Against diseases, vaccine components and how to develop vaccines

achamila press :Dr.Mohamed Al-Rifai- Minister of  Health -The new kingdom of Atlantis (land of wisdom)

We are surrounded by germs, both in the environment we live in and in our bodies. When a person is sensitive and encounters a harmful organism, it can lead to illness and death

The body has many ways to defend itself against pathogens (disease-causing organisms). Skin, mucus, and cilia (the microscopic hairs that carry debris away from the lungs) act as physical barriers that prevent pathogens from entering the body in the first place

When the body is infected with a pathogen, the body activates its defenses, called the immune system, so the pathogens attack and are destroyed or defeated

The body’s natural response

A pathogen is a germ, virus, parasite or fungus that can cause disease inside the body. Each pathogen is made up of several subparts, usually associated specifically with that pathogen and the disease it causes. The sub-section of the pathogen that causes the formation of antibodies (antibodies) is called the antigen. Antibodies produced in response to a pathogen’s antigen are an important part of the immune system. Opposites are soldiers in your body’s defense system. Each antigen or soldier in our system is trained to recognize a specific antigen. We have thousands of different antibodies in our bodies. When the human body is first exposed to an antigen, it takes time for the immune system to respond to that antigen and produce its own antibodies

Meanwhile, the person is susceptible to infection

Once produced, the antigen-specific antibodies work with the rest of the immune system to destroy the pathogen and stop the disease. In general, antibodies to a particular pathogen do not protect against another pathogen unless the two pathogens are exactly alike, such as in cousins. Once the body produces antibodies during its initial response to the antigen, it also creates antibody-producing memory cells that survive even after the antibodies have overcome the pathogen. If the body is exposed to the same pathogen again, the antibody response will be much faster and more effective than the first time because the memory cells are ready to release the antibodies against that antigen

This means that if a person is exposed to a dangerous pathogen in the future, their immune system will be able to respond to it immediately, thus protecting the person from disease

?How do vaccines help

Vaccines contain attenuated or inactivated parts of a specific organism (antigen) that trigger an immune response within the body. Modern vaccines contain the blueprint for antigen production rather than the antigen itself. Regardless of whether the vaccine consists of the antigen itself or a blueprint that allows the body to produce the antigen, this attenuated version will not cause illness in the person receiving the vaccine, but will prompt the immune system to respond as closely as possible as if it were its first response to the actual pathogen

societal immunity

When a person receives the vaccination, it is very likely that they will be protected against the target disease. However, not everyone can be vaccinated. People who have underlying health conditions that weaken their immune system (such as cancer or HIV) or who have severe allergies to certain vaccine components may not be able to receive certain vaccines. These people can still be protected if they live among other people who have been vaccinated. When a large number of members of the community are vaccinated, it will be difficult for the pathogen to spread because most people exposed to it are immune. Thus, the more people vaccinated, the less likely it is that people who cannot be protected by vaccines will be at risk of harmful pathogens. This is called societal immunity, or what is generally known as herd immunity

This is especially important for people who not only cannot be vaccinated, but may also be more susceptible to the diseases against which we are vaccinated. No single vaccine provides 100% protection, and community immunity does not fully protect people who cannot be vaccinated safely. But, through herd immunity, these people will have a great deal of protection thanks to the vaccination of the people around them

Vaccination protects not only you, but also members of the community who cannot be vaccinated. Don’t hesitate to get vaccinated if you can

Some vaccines require multiple doses, given weeks or months apart. Sometimes, this is necessary to allow the production of long-lived antibodies and the formation of memory cells. In this way, the body is trained to combat the specific disease-causing organism by creating a memory of the pathogen in order to combat it quickly in the event of future exposure

Throughout history, humans have developed vaccines against a number of life-threatening diseases, including meningitis, tetanus, measles and polio

In the early twentieth century, polio was a global disease, paralyzing hundreds of thousands of people each year. By 1950, two effective vaccines against this disease had been developed. However, in some regions of the world, particularly in Africa, vaccination is still not common enough to stop the spread of polio. In the eighties of the last century, a unified global effort began to eradicate polio from the face of the earth. Over many years and decades, polio vaccination has spread to all continents, through routine immunization visits and mass vaccination campaigns. Millions of people, mostly children, have been vaccinated, and in August 2020, the African continent was certified polio-free, joining all other regions of the world that have eradicated polio, with the exception of Pakistan and Afghanistan

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?How do vaccines evolve

of the disease-causing organism or on the protozoa to form very small fragments. It also contains other ingredients to maintain the safety and efficacy of vaccines. These last ingredients are included in most vaccines and have been used for decades in billions of vaccine doses

Each component of the vaccine has a specific purpose and is tested in the manufacturing process. All ingredients are tested for safety

antigen

All vaccines contain an active ingredient (the antigen) that elicits an immune response or the blueprint for active ingredient formation. The antigen may be a small part of the disease-causing organism such as a protein or sugar, or the whole organism may be in its attenuated or inactivated form

preservatives

Preservatives prevent contamination of the vaccine after opening the vial that contains it if it is used to vaccinate more than one person. Some vaccines do not contain preservatives because these vaccines are stored in single-dose vials and disposed of after single-dose administration. Diphenoxyethanol is the most common preservative and has been used for many years in a number of vaccines and is used in a range of child care products. It is considered a safe substance for use in vaccines because it is low in toxicity in humans

Stabilizers

Stabilizers prevent chemical reactions inside the vaccine and prevent the vaccine components from sticking to the vaccine vial

Stabilizers can be sugars (lactose and sucrose), amino acids (glycine), gels, and proteins (yeast-derived recombinant human albumin)

surfactant active substances

The surfactants maintain a good mixture of all components of the vaccine. It prevents the sedimentation and agglomeration of the elements in the liquid form of the vaccine. It is also often used in foods such as ice cream

Remaining material

Residues are very small amounts of various preparations used during the manufacture or production of vaccines and are not active ingredients in the finished vaccine. These preparations vary depending on the manufacturing process used and may include egg proteins, yeast or antibiotics. The remaining amounts of these preparations that may be present in a vaccine are so small that they are measured as parts per million or parts per billion

diluents

A diluent is a liquid used to dilute a vaccine to the correct concentration before use. The most commonly used diluent is sterile water

Auxiliary materials

Some vaccines also contain adjuvants. The adjuvant improves the immune response to the vaccine, sometimes by keeping the vaccine at the injection site for a little longer or by stimulating the local immune cells

The adjuvant may be a very small amount of aluminum salts (eg aluminum phosphate, aluminum hydroxide, or potassium-aluminum sulfate). It has been proven that aluminum does not cause any health problems in the long term, and humans ingest aluminum regularly through eating and drinking

?How do vaccines evolve

Most vaccines have been in use for decades and millions of people are safely vaccinated with them each year. Like all medicines, each vaccine must undergo extensive and rigorous testing to ensure its safety before it can be used in a country-specific vaccination programme

In the first place, every vaccine under development must undergo screening and evaluation processes to determine which antigen should be used to generate the immune response. This preclinical phase is carried out without human testing. The experimental vaccine is first tested on animals to assess its safety and ability to prevent disease

If the vaccine elicits the desired immune response, it is then tested in human clinical trials in three phases

level 1

The vaccine is administered to a small number of volunteers to assess its safety, confirm that it generates an immune response, and determine the appropriate dose. In general, vaccines at this stage are tested in healthy young adult volunteers

Stage 2

The vaccine is then administered to several hundred volunteers to further evaluate its safety and ability to generate an immune response. Participants in this phase of testing have similar characteristics (such as age and gender) to those of the people targeted by the vaccine. Multiple trials are usually conducted at this stage to evaluate different age groups and different vaccine formulations. A group of unvaccinated people is usually included at this stage as a comparison group in order to determine whether changes in the group of vaccinated people are attributable to the vaccine or occurred by chance

Stage 3

At this stage, the vaccine is given to thousands of volunteers, and it is compared to a similar group of people who were not vaccinated with the vaccine but who received a product used as a basis for comparison, to determine the efficacy of the vaccine against the disease that is intended to prevent it and to study its safety in a much larger group of people. Most of the time, phase III trials are conducted across multiple countries and multiple sites within a country to ensure that vaccine performance results are applicable to several different populations

During Phase II and III trials, information about which volunteers received the vaccine under test or the product used as a comparison is hidden from the volunteers and scientists conducting the study. This measure is called “blinding” and is necessary to ensure that volunteers and scientists are not influenced in their assessment of safety or efficacy by who received which product. After the end of the experiment and obtaining all the results, information about the identity of the person who received the vaccine and who received the product used as a basis for comparison is revealed to the volunteers and scientists who conducted the experiment

When the results of all these clinical trials are available, a series of steps are required, including procedures to review efficacy and

Safety for regulatory approval and public health policy approval. Officials in each country closely review the study data and decide whether or not to authorize the use of the vaccine. The vaccine must be proven safe and effective in a wide range of the population before it is approved and used in a national immunization programme. A very high standard of vaccine safety and efficacy is established, given that the vaccines are given to otherwise healthy people who do not have the specific disease in question

Additional monitoring is carried out continuously after the start of the vaccine. Systems are in place to monitor the safety and efficacy of all vaccines. This enables scientists to track the effect and safety of vaccines, even when used in a large number of people, over a long period of time. This data is used to adjust policies on the use of vaccines in order to optimize their effect and also allows the vaccine to be safely traced throughout its use

When the vaccine is used, it must be monitored frequently to make sure it is still safe

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