It's a different strain of meningitis. Previously, this vaccine was low on the radar - there were very few infections, mostly limited to old people in hospitals. Since 2011, there has been a spike in the number of meningitis W infections in freshers, which is why the vaccine is recommended for people starting university (an environment where people from all around the world, with different immunities, live in close quarters... yeah not rocket science to see how infection spreads). You can get them from your GP before you go or upon arrival from your uni nurse.
It's not a bad shot at all compared to some other vaccines. Bacterial meningitis, though rare, is nasty business - an infection in the brain can be deadly and leave neurological damage that a person may never recover from.