GSK investigational MMRV vaccine shows comparable immunogenicity to licensed MMRV in healthy children

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Human vaccines & immunotherapeutics Published May 27, 2026 Medically reviewed May 27, 2026 Study authors: Habib Md Ahsan, Hughes Teena, Huang Li-Min, Deseda Carmen, Zavadska Dace, Povey Michael, Raja Rajara… PubMed ↗ DOI ↗ By Dr. Sofia Müller, MD · Lifespan & Whole-Person Care

Key Takeaway

Consider that an investigational MMRV vaccine showed comparable immunogenicity to a licensed vaccine in primed children, with a similar safety profile.

This randomized, multi-country phase II trial enrolled 801 healthy children aged 4-6 years who had received a first dose of any MMRV-containing vaccine in their second year of life. Participants received one dose of a GSK investigational MMRV vaccine (MMRVNS; three formulations) or a licensed MMRV vaccine (two lots). The primary outcome was immunogenicity assessed at Day 43 post-vaccination.

Main results showed that antigen-specific antibody geometric mean concentrations and seroresponse rates were comparable between MMRVNS (regardless of formulation) and MMRV recipients. Exact numbers, effect sizes, and p-values or confidence intervals were not reported.

Safety was assessed up to Day 181. Administration-site pain occurred in 29.0% to 39.0% of participants. Systemic drowsiness was reported in 9.0% to 15.9%. Unsolicited adverse events, mostly upper respiratory tract infections, occurred in 18.5% to 27.2% of participants. At least one serious adverse event occurred in each group; none were considered vaccine-related, and all resolved except for one reported fatality. Tolerability was similarly acceptable.

Key limitations include the phase II design, lack of reported effect sizes or statistical comparisons, and the investigational nature of the vaccine. Practice relevance is limited to supporting further clinical development of MMRVNS.

Study Details

Study typeRct

Sample sizen = 801

EvidenceLevel 2

PublishedDec 2026

PMID42189573

View Original Abstract ↓

Two-dose childhood vaccination against measles, mumps, rubella, and varicella is widely recommended. Quadrivalent (MMRV) vaccines can be used for one or both immunizations against these diseases. In some countries, e.g. the United States, only one MMRV vaccine is licensed. Availability of another MMRV vaccine could strengthen supply resilience, optimal vaccine coverage, and disease control. In this phase II, single-blind, multi-country study, healthy children aged 4-6 y, previously primed with a first dose of any combination of measles/mumps/rubella/varicella-containing vaccine(s) in their second year of life, were randomized 2:2:2:1:1 to receive one dose of a GSK investigational MMRV (MMRVNS; three formulations) or a licensed MMRV vaccine (two lots). Immunogenicity was assessed at Day 43 post-vaccination. Adverse events (AEs) were recorded up to Day 4 (solicited administration-site and systemic AEs), Day 43 (solicited systemic and unsolicited AEs), and Day 181 (serious AEs [SAEs]) post-vaccination. Of 801 participants enrolled, 796 were vaccinated and 765 completed the study. Antigen-specific antibody geometric mean concentrations and seroresponse rates were generally comparable between MMRVNS (regardless of formulation) and MMRV recipients. Administration-site pain (29.0%-39.0% of participants) and systemic drowsiness (9.0%-15.9%) were the most common solicited AEs. Unsolicited AEs (mostly upper respiratory tract infections) were reported in 18.5%-27.2% of participants. At least one SAE (none considered vaccine-related) occurred in each group. Except for one reported fatality, all SAEs resolved. Compared to the licensed standard-of-care MMRV vaccine, the investigational MMRVNS formulations generated comparable immune responses and had a similarly acceptable safety profile, when administered as second dose. These results support further clinical development of MMRVNS.