What are vaccines, how do they work and why people doesnt trust them?

Vaccines have saved over ten million lives since their inception and have made it possible to eradicate deadly diseases such as smallpox. However, in many countries around the world, distrust in vaccines is growing from year to year. The World Health Organization has listed the suspicion of vaccines among the 10 biggest threats to human health in 2019.   In order to understand vaccines and vaccination, as a technique of immunization, it is necessary to say something about immunity. Immunity is a medical term that describes the body’s ability to defend itself against infections, diseases, or other biological and chemical hazards. It can be natural or artificial, active or passive immunity.   Immunity basically includes a networked system of reactions of the organism by which the organism, in order to protect, reacts to pathogens (viruses, bacteria, parasites), cancer cells, or other chemical/biological threats to the organism.   After, for example, a pathogen (virus, for example) enters the body, it binds to a host cell via specific proteins, thus starting its multiplication. The natural, immune, response of the cell is the production of specific proteins - antibodies that aim to neutralize the pathogen. In most cases, our body successfully defends us in this way, but due to various factors, our immune system sometimes loses the battle with pathogens, and we get sick. In order to provide an effective immune response to certain pathogens, primarily viruses, immunization (creation of immunity by artificial means), which is vaccination, has been successfully applied.       What is a vaccine and how does it work?   A vaccine is an isolated virus (to the extent that it cannot cause disease) or part of a virus whose role is to trigger an immune response, create antibodies to a given virus, and more importantly, “memorize”, which allows the body to make antibodies quickly enough. Such as already pointed out, when the weakened virus enters the host organism, the immune system produces antibodies through a series of cross-linked reactions. Furthermore, the organism remembers the “virus” and is ready to react very quickly and efficiently in case this virus attacks the given organism again later. With some vaccines, this “memory” is permanent, with others, it is not, so revaccination is necessary.   Viral vaccines are divided into three major groups: Attenuated vaccine, inactivated, and DNA vaccines, depending on the component of the vaccine that is supposed to elicit an immune response.   When it comes to an Attenuated vaccine, we are talking about an original, related, or hybrid virus. Inactivated or dead vaccines, as the word itself, says, contain dead parts of the virus (the virus is not capable of performing basic physiological functions in order to survive), while DNA vaccines contain a viral gene. DNA vaccines are produced and used in such a way that they enable the creation of a virus after being introduced (a vaccine that contains a viral gene) into the body, causing a strong immune response.       Vaccination history   The vaccine derives its root from the Latin name for cow (vacca), the name of the cowpox virus (vaccinia). This virus was first injected into a boy for the purpose of immunization in 1796 by Edward Jenner, and thus the history of the vaccine began.   Since then, a large number of vaccines have been developed that have significantly reduced mortality worldwide, thus achieving one of the greatest successes not only in immunology but in medicine in general.   Some of the more important vaccines are the vaccine against polio, tuberculosis, hepatitis, etc.       Vaccination success   It has already been mentioned in the introductory part that the vaccine saved over ten million human lives. The following is a tabular presentation of the number of patients with various diseases before and one year after the discovery and application of the vaccine.       What conditions should the vaccine fulfill?   That it is effective and safe, that provokes an immune response (which enables defense against the disease) in the vast majority of vaccinated persons (it does not have to in all of them), without leading to disease or other severe side effects.   To induce a cellular (cellular) response, or simply to activate specific subtypes of white blood cells, so-called cytotoxic T-lymphocytes, which destroy virus-infected cells.   To induce long-term immunity, thus avoiding, or minimizing, the need for its re-application (revaccination).   That it is practical, which is reflected in the fact that it is stable and relatively easy to transport, that it is easy to apply, that it is as cheap as possible, and more.   The specific conditions that the vaccine must meet, as well as all practical steps in the research and creation of new vaccines, are defined primarily by the World Health Organization, but also by each individual country. Thus, in Serbia, in accordance with the law, the Agency for Medicines and Medical Devices is the umbrella institution that approves the use of medicines, research related to medicines.       Why do some people refuse to get vaccinated?   Vaccines have caused suspicion since they appeared. In the past, people were skeptical for religious reasons because they thought vaccination was unclean.   In 1800, the first anti-vaccination groups began to operate throughout Great Britain. They suggested isolation as an alternative.   The first anti-vaccination group in the United States was created after the visit of the British anti-vaccination activist William Thebes in 1870.   One of the key figures in anti-vaccination movements, lately, is the British doctor Andrew Wakefield. In 1988, he published a paper that falsely linked autism and intestinal disease to the MMR vaccine. The MMR vaccine is a DNA-type viral vaccine, given to young children against smallpox, mumps, and rubella. Although his work has been discredited and his license to practice medicine has been revoked for falsifying scientific results, there has been a significant drop in vaccinated children in the UK thanks to his views. In 2004 alone, one hundred thousand fewer children in the UK received the MMR vaccine than before, which led to a significant increase in the number of patients.   Vaccine issues are increasingly politicized. Italian Interior Minister Mateo Salvini supported anti-vaccination groups, while US President Donald Trump linked the vaccine to autism without evidence, but then called on parents to vaccinate their children.   An international study on attitudes towards vaccination has shown that overall trust in vaccines is positive, but trust is lowest in the European region. The French have the least trust in vaccines.       What is the risk?   Vaccination of a large part of the population helps prevent the spread of the disease, which in turn provides protection to those who do not have immunity or who for certain reasons cannot be vaccinated. This is called collective immunity.   The percentage of people who need to be vaccinated to maintain collective immunity depends on the disease. For smallpox, it is 95% of the total population, while for polio it is for the maintenance of the collective immunity need to be vaccinated 80% of the population.   According to the World Health Organization, over two million human lives are saved each year thanks to the vaccine. According to the same organization, they are least vaccinated in countries with poor health systems such as Angola, Congo, and Afghanistan, but this organization also warns that citizens of richer countries are increasingly forgetting what the vaccine means and what the world looked like without it.