Is it necessary to let toddler have the meningococcal vaccination?

Since this is not a compulsory vaccine, it's ultimately up to you whether you want to give the vaccine - but you should also know what vaccines are and what they're used for to help you make decisions about all optional vaccines! Vaccines are weakened/inactive versions of the actual thing you're vaccinating against - used to let your body be exposed to it and figure out a "battle plan" to fight against it, so that it is prepared if the actual virus attacks the body. Something like army training before a war? Therefore, having a vaccines does NOT mean you will never contract it - just that your body is better equipped to fight it. If possible, I'd say that you should take whatever vaccines is available because it would help to reduce its effects if your child ever contracts the real virus - while it may not be vulnerable if you don't travel much, but the people around you might. Your family, friends, relatives, even the people in public that you come across! As for the cost, most vaccines are payable by Medisave or CDA if you take them in polyclinics/CDA-approved pediatricians - so do consider getting it done if possible :)