To support high school students to develop knowledge they need to adhere to control measures during the pandemic, a peer-based educational intervention on SARS-CoV-2 was developed and its impact was evaluated. Multistage random sampling was used. The 50 min peer-based intervention was conducted by final year medical students. Baseline and post-intervention knowledge and attitudes were assessed. Significance was tested by McNemar's/Wilcoxon rank tests. Of 518 participants (mean age 17.8 years ± 0.43), 81.0% did not receive any school-based education on SARS-CoV-2. After intervention, the knowledge score improved from 65.2% to 81.6%, attitudes from 63.2% to 70.8% (both p < 0.0001). The effect size after the intervention compared to pre-intervention showed moderate improvement of knowledge, but not attitudes (d = 0.46 and d = 0.18, respectively). Pre- and post-intervention, females, students in non-science programs, living in cities < 250,000 inhabitants had lower knowledge, while fewer males, non-science program students, living in smaller cities presented positive attitudes. Before intervention, 67.0% students correctly named SARS-CoV-2 preventive methods and 73.6% were concerned COVID-19 is a serious disease; these improved after intervention (to 80.1% and 86.3%; p < 0.0001). The intervention was not very successful in increasing the intent to vaccinate for COVID-19 (pre-intervention 52.9%, post-intervention 56.4%; p < 0.007). Peer-based teaching for high school students can be effective in increasing SARS-CoV-2 knowledge and awareness. More efforts are needed to improve attitudes and enhance acceptance of vaccination against COVID-19.
Keywords: SARS-CoV-2; adolescents; attitudes; intervention; knowledge.