[jksk61]

If you know the enemy and know yourself, you need not fear the result of a hundred battles. If you know yourself but not the enemy, for every victory gained you will also suffer a defeat. If you know neither the enemy nor yourself, you will succumb in every battle.

Sun Tzu.

How do you think you can devise a vaccine if you don't know the virus? They experiment to find out what are the weaknesses of the enemy (i.e. proteins and other markers), so that they can target it. If the next pandemy is caused by a similar strain: ta-dam you have the vaccine already (or at least you know what to target).