I received a letter from up where students are encouraged to get vaccinated against bacterial meningitis. they also recommend the 3 in 1 + chicken pox. my child received these vaccinations in early childhood. do i have to order all 3 again at 18?

Your choice: The early vaccines covering MMR and chickenpox are generally effective in bringing protection to 90-95% of the population & lasts for life. However if the kid falls into the 5-10% that did not respond to the earlier doses, a community outbreak exposes them to a higher that normal risk of any of these illnesses. The same goes for meningitis, which does not have long term (decades) of effectiveness.