Answer:
There are very different factors that make modern pandemics different from the pandemics of the past, but the easiness that modern pandemics have to spread globally more rapidly, is one of the most important.
Explanation:
First of all, let's take a look at pandemics. They are outbreaks of certain diseases, that come from viruses, bacteria, etc. This is their major characteristic, they go out of total control and cross territories. Now, considering modern transportation. Pandemics can grow at a very alarming pace. Airplanes, light trains, metro, cruisers, and many other modern sources of transportation make Pandemics a phenomenon with more easiness of spreading and impact on society.
In the second hand, even though medicine and research have improved a lot. They cannot prevent spreading at such large scales of speed and space. Because they travel at such big speeds that the prevention is almost unreachable. The best resources of medicine still cannot make her pass from reactive. Because there are just not enough to prevent the spread. Let's look at an example: there are no medical or technological resources to know all the conditions a regular person can have, at any moment. We have no cameras or scanners that could tell us the specific condition of somebody in real-time. But we do have vehicles that can take an infected person from one country to other in less than 1 hour.
