Parachutes solve a simple to model physics problem with few variables.<p>Vaccines or drugs are injected into an incredibly complicated biological system and interact with the immune system, cell signalling pathways, gene expression, thousands of different receptor bindings, and more.<p>For vaccines, the immune system itself is immeasurably complex. You can teach it the wrong things and be stuck with that lesson for life.<p>Interfering with signalling pathways can give you incurable cancer ten years down the line, or leave you with terrible disorders that ruin your quality of life.<p>How many times have drugs interfered with pregnancy and caused children to be born with birth defects and learning disorders? There's a reason we study these things.<p>This analogy is a very poor fit.<p>Edit: why is this being downvoted? Are people really eager to try the new prophylactics? While designing a fix for Coronavirus is incredibly important, we can't throw out all we know about safety. Why don't you offer a counter argument so we can discuss?<p>Intervention in cases where it is obvious the patient won't survive is worth considering, but we shouldn't proactively give healthy people something we aren't sure is safe.