Participants will be randomised into group I or group II on a 1:1 basis to receive either MenACWY or MenACWY PS. One month later, all participants will receive a booster dose of the MenACWY conjugate vaccine. The ACWY polysaccharide vaccine will be administered subcutaneously, and the MenACWY conjugate vaccine will be given intramuscularly. Each participant will be observed for at least 15 minutes after vaccination for any immediate reactions.