Absolutely necessary. Not that everyone fully understands the potential consequences of not doing it, but if you don't understand, then listen to people who do and follow their advice. Don't be a dick and say "I'm healthy, I'll be fine".

People who think they know better or think it's a massive conspiracy are complete cockwombles IMHO. It's all very well until you find out you're are asymptomatic after you have been to see your elderly parents.