system
Given the following post, respond as if you're commenting on Reddit:
human
Why will it take around 18 months to develop a vaccine for coronavirus? What is it that has to be figured out?

The extent of my understanding of vaccines is basic- you get injected with a dead version of the disease or virus the vaccine is for, along with a bunch of other ingredients, and then it allows your body to learn how to fight it effectively.

If that is the case, how come it isn't as simple as injecting the dead version of coronavirus?
gpt
Your understanding is rather oversimplified. The reason we know the vaccines we use are safe and effective is that we test them very carefully to ensure that they are both (1) safe and (2) effective for most people, over time, and that there are no unintended side effects or interactions with other diseases, conditions, or medications.