Safety and Tolerance of a Novel MMR (Measles, Mumps, and Rubella) Vaccine in Indian Children: A Real-World Evidence Study.

Background Measles, mumps, and rubella continue to cause outbreaks and serious complications in many regions. Routine childhood vaccination is the most effective strategy for preventing these infections. Multiple MMR vaccines are used in India, including both domestic and international formulations. The objective of this study was to evaluate the safety and tolerability of the ZyVac MMR vaccine (Zydus Lifesciences Ltd., Ahmedabad, Gujarat, India) administered during routine paediatric practice. Methods This retrospective post-marketing safety study was conducted across nine paediatric centres in India from August 2025 to November 2025. Children aged 9-26 months who received a single 0.5 mL subcutaneous dose of ZyVac MMR vaccine were included. Solicited local and systemic adverse events (AEs) were recorded on Day 0 retrospectively and on Day 7, prospectively, wherein Day 0 was the day of vaccination. Unsolicited or serious AEs were monitored through Day 7. Caregivers and clinicians independently rated vaccine tolerability using a standard global assessment scale. Descriptive statistics were used to summarise AE incidence. Results A total of 381 children were vaccinated. No serious AEs were reported. Overall, 3.67% of children experienced AEs. Fever (2.1%) and rash (0.79%) were the most common reactions. Local AEs, including pain and redness, occurred in 0.26% each. One child reported mild rhinorrhoea. All events were mild, brief, and resolved without treatment. More than 99% of caregivers and investigators rated tolerability as "excellent" or "good." Conclusion ZyVac MMR demonstrated an excellent safety and tolerability profile in Indian children during routine clinical use, with only mild, self-limiting AEs observed. These findings support its inclusion in early childhood immunisation schedules and reinforce current recommendations in India for timely MMR administration to strengthen population-level immunity.