An open-label, randomized controlled, non-inferiority study of co-administration of OCV, TCV and MR vaccines among children 12 to 59 months of age in Dhaka, Bangladesh will be conducted. Children who did not receive any of the aforementioned vaccines will be included in the study. This study will be conducted among 2117 children of 12-59 months of age residing in Mirpur area (wards 4, and 6-16) of Dhaka north and Kamrangirchar, Hazaribag and Rayerbazar areas (wards 14, 22, 56, 57, and 58) of Dhaka south to enroll the required number of participants. Only children who have not previously received the vaccines will be enrolled. The findings of this study are likely to have a significant impact on vaccine co-administration strategies for campaign and routine immunization programs. The participants will be randomly assigned to one of the six arms. The numbers are defined for each arm based on the sample size calculation. A list of children who did not receive MR, OCV and TCV will be prepared before enrollment by trained study staff (TSS). The TSSs will visit households in the defined study area and ask if the parents/guardians of children aged 12-59 months are willing to participate in the study. If they show willingness to participate, the TSSs will check their vaccination cards (if available) and prepare the list of potentially eligible children who have not received OCV, TCV and MR based on their vaccination card status and verbal statement (if vaccination card is not available). The investigators will enroll the participants after obtaining informed written consent and collect around 2-3 ml blood from each participant at different time points.