It is still difficult for many people to understand the concept of a vaccine, how it works and its importance. However, in a simple way, the vaccine can be understood as a “preventive remedy”, so its function is prophylactic, that is, the vaccine makes the recipient's body resistant to a certain disease, which prevents its onset and subsequent spread in the population. The importance of getting vaccinated lies precisely at that point. When we get vaccinated we're not only protecting ourselves, but also our family, friends, and even those we don't know.

The first vaccine appeared in 1798 and was developed through the observations and studies of Edward Jenner. The English scientist identified that some workers were not infected with smallpox because they had already been infected with bovine smallpox, a milder type of disease. Based on this framework, Jenner understood that the biological substances that cause diseases, when introduced into patients in an attenuated or inactive form, could stimulate the immune system to recognize the bacteria or virus and produce antibodies against the disease. In this case, the vaccine would ensure that the patient's body develops defenses so that, in the case of coming into contact with the cause of the pathology, it can combat it.

Over the years, vaccines have undergone improvements and new discoveries have been made, but his idea remains the same as that discovered by Edward Jenner. Therefore, most vaccines still act on the body today simulating the effect of when we come into contact with an infectious agent and, as a consequence, our immune system creates antibodies to protect us from it. However, with the vaccine there is no need to suffer from the disease to become resistant to it. Vaccination stimulates the body's defenses against a certain disease without the individual having to become ill.

Among the serious diseases that vaccines have the power to protect us, is cancer. The HPV vaccine can prevent the onset of penile cancers, throat and anus in boys and cervical, vulvar, vaginal, and anal cancers, in addition to precancerous lesions, genital warts, and HPV infections in girls. The vaccine can be taken free of charge at the SUS, however, due to misinformation, many fail to vaccinate their children, since they associate the vaccine with encouraging early sexual initiation, since the HPV vaccine prevents the virus from being transmitted through sexual intercourse and is applied to children between girls between 9 and 14 years old and boys aged 11 to 14. Because of this, The numbers of the disease have been increasing over the years. However, this age group was chosen because of the high exposure to antibodies and the lower probability of having sexual contact with the virus.

Also in November 2020, researchers from the University of Oxford announced that their tests to develop a vaccine against breast cancer triple negative, the most serious, was 100% effective when tested on mice. The vaccine has been developed since 2009 and, like all the others, has years of studies until it is applied to the population. However, in times of crisis, such as the spread of COVID-19 in the population, research and tests are duplicated and international collaboration between researchers is intensified in order to find a Coronavirus vaccine with speed and efficiency. Even so, the vaccines are produced in the laboratory with great technical, scientific and sanitary rigor. It is important to note that there is a great effort by health professionals to ensure that vaccines do not present side effects or, if there are effects, are as mild as possible. In addition, dense research is also carried out so that vaccines do not cause the diseases they want to combat.

Another important detail is that vaccines are not always produced with the biological agents that cause the diseases. Therefore, vaccines can be composed of Toxins from the invading organism, as in the vaccine against Tetanus; of the pathological agent in an attenuated state, as in the vaccine against Measles; or inactive, as in the vaccine against HPV and BCG. There are also vaccines that are composed of the antibodies that fight the disease and not its causative agent, such as the Hepatitis B vaccine.

Finally, vaccines prevent and save lives. But to do this, attention must be paid to the vaccination schedule and to the booster doses so that diseases that have already been eradicated do not claim victims again. In this way, it is possible to understand why the vaccine is a collective pact for health, since it is a disease prevention measure that depends on the collaboration of each of the citizens.

Text by Letícia Barbosa