I have just returned and didn't have any travelling from the UK.
I did check with my GP prior to going and the advice was that if I was staying in the tourist/populated areas there was no requirement.
I have however, had possibly the worst tummy upset that I have ever had. Almost 3 weeks to clear ! That was despite drinking bottled water and using it to brush teeth.
Don't let that put you off though - fascinating country.
You don't 'need' any in the sense that you will be refused entry to Tunisia, or return to the UK, without them but some are recommended as stated in the previous post..