Prevention does exist in the Shariah, and it seems even more: it is a religious principle. Imam Bukhari (ra) tells a story from the time of Caliph Umar (ra), perfectly illustrating the prophet’s (pbuh) guidelines for the prevention of pandemics and diseases in general.
Hazrat Umar (ra) was heading towards the land of Sham with a group of Muslims to inspect the situation in the country: arriving near Sargh, Hazrat Abu Ubaydah Aamir Ibn Al-Jarrah (ra) informed him that the plague was raging in these lands. Hazrat Umar (ra) consulted with the Muhajireen, and subsequently the Ansar, who were torn between the desire to continue the journey, and to avoid entering an infected region. Other companions, of the tribe of Quraish, who had made the Hijrat after the conquest of Mecca, unanimously said: “We think it is better to turn around, and that you do not expose the Muslims to this disease.”