This is the first pilot study on alternative conceptions and obstacles pertaining to pneumonia in adolescents of different school vulnerability indexes. Countries with low socioeconomic levels are disproportionately affected, with Latin America and the Caribbean (LAC) being the second-most affected area in the world, after sub-Saharan Africa. In spite of this fact, pneumonia is not included as an important component within the contents of the microbiology curriculum unit in the natural science school program. Therefore, we wanted to study how students knew about this topic by putting One Health into action by building and validating qualitative and quantitative questionnaires, put together by different experts in pedagogy, didactics, microbiology, and veterinary to find out what students knew about pneumonia and their misconceptions about it. A total of 148 students (in 8th and 9th grade) participated in this survey. The results reveal that no statistically significant differences between the different scholar grades (p = 0.3360 Pearson chi∧2) or genders (p = 0.8000 Fisher's exact test) presented higher or lower School Vulnerability Index (SVI). Regardless of the social stratum or the level of vulnerability of the students, they have heard about this disease primarily through their family/relatives, maintaining a superficial notion of the disease, learning wrong ideas about microorganisms and treatments that can contribute to the risk to public health.