Seeking ways to encourage broad compliance with health guidelines during the pandemic, especially among youth, we test two hypotheses pertaining to the optimal design of instructional interventions for improving COVID-19-related knowledge, attitudes, and behaviors. We randomly assigned 8376 lower-middle income youth in urban India to three treatments: a concentrated and targeted fact-based, instructional intervention; a longer instructional intervention that provided the same facts along with underlying scientific concepts; and a control. Relative to existing efforts, we find that both instructional interventions increased COVID-19-related knowledge immediately after intervention. Relative to the shorter fact-based intervention, the longer intervention resulted in sustained improvements in knowledge, attitudes, and self-reported behavior. Instead of reducing attention and comprehension by youth, the longer scientific based treatment appears to have increased understanding and retention of the material. The findings are instrumental to understanding the design of instruction and communication in affecting compliance during this and future pandemics.