Do we need to revaccinate ourselves if the vaccine effect wanes?

Q: If we take vaccination for a virus (meningitis) and it is effective for 4 years, then do we need to get ourselves re-vaccinated? Are there any side effects of regaining the disease?

A:We do not currently have vaccines for viral meningitis. If the effect of a vaccine wanes after some time, we should give a booster dose to retain the protectively from that particular disease as per the recommendations.