evidence: The smallpox vaccine was far from perfect, but it got the job done. The COVID-19 vaccine might be similar. If we were designing the perfect vaccine, we’d want it to be completely safe and 100 percent effective. It should be a single dose that gives you lifelong protection, and it should be easy to store and transport. I hope the COVID-19 vaccine has all of those qualities, but given the timeline we’re on, it may not.