Vaccination challenges: factors that influence the effectiveness of vaccines

Introduction: Although the World Health Organization (WHO) has appointed vaccination as one of the main prophylactic measures against infectious diseases, there is still a considerable number of deaths every year from vaccine-preventable diseases. These mortality data can be explained by several factors related to the effectiveness of these immunobiologicals, such as the genetics of each individual and the environment in which they live. Therefore, this work aims to point out some of these factors and discuss about them. Methodology: This is a literature review carried out in the following databases: Google Scholar, PubMed and WHO bulletins. Results and Discussions: Studies show that aspects such as genetics, sex, age and immune system diseases can interfere with the performance of immunizers, as they alter the expected response of the organism against vaccine antigens. In addition, the environment proved to be a strong influencing factor for the response against immunizing agents, being responsible for positive and negative variations in the humoral response. Malnutrition, obesity, diabetes, hypertension and psychological stress are among the factors with a negative impact on the biological production of antibodies after vaccination. Conclusion: Therefore, the data presented here make clear the interference of several factors for a satisfactory response to immunizers, explaining the still high rate of deaths from infectious diseases in patients already vaccinated.