EU Expands MenQuadfi Age Indication, Allowing Infants from Six Weeks to Receive Quadrivalent Meningococcal Vaccine

Although invasive meningococcal disease is uncommon, it can cause meningitis or sepsis within a short period, and infants under one year of age are among the groups at highest risk. The European Commission has now lowered the approved age for Sanofi’s quadrivalent conjugate vaccine MenQuadfi to six weeks after birth, allowing prevention to begin at the start of the infant vaccination series.

The approval covers meningococcal serogroups A, C, W, and Y, expanding MenQuadfi’s previous indication, which was limited to people aged 12 months and older. However, the vaccine does not cover serogroup B and therefore cannot be regarded as a single option for preventing all meningococcal infections.

The approval was based primarily on the Phase 3 MET58 trial. The study enrolled 1,660 healthy infants across seven European countries, compared MenQuadfi with another quadrivalent vaccine, Nimenrix, and administered them alongside locally recommended routine childhood vaccines. The main vaccination regimen consisted of two primary doses during infancy followed by a booster dose at 12 to 18 months—the “2+1” schedule. The study also evaluated a “3+1” schedule in a smaller group.

The trial results were not equally clear across all four serogroups. After the booster dose, the geometric mean antibody titers induced by MenQuadfi against serogroups C, W, and Y met the non-inferiority criteria compared with Nimenrix, but serogroup A did not meet the primary analysis threshold. The research team subsequently conducted a post hoc analysis using seroresponse rates among individual participants, which produced non-inferiority results for all four serogroups.

This difference also defines the limits of interpretation. Because invasive disease is rare, MET58 did not directly compare how many cases of meningitis or sepsis the two vaccines could prevent. Instead, it estimated protection based on bactericidal antibody responses; the post hoc analysis was not the prespecified primary test. Therefore, approval for use in infants does not mean that a reduction in clinical cases has been directly demonstrated in a large trial.

Regarding safety, the study identified no new concerns and did not observe MenQuadfi weakening immune responses to routinely administered vaccines given at the same time. The EU approval allows it to be co-administered with specified six-in-one, rotavirus, and pneumococcal vaccines, helping reduce additional visits and vaccination scheduling. For infants at higher risk of exposure to serogroup A, the “3+1” schedule may be considered.

Regulatory authorization is only the first step toward routine immunization. Each country must still decide whether to include MenQuadfi in its infant vaccination schedule based on locally circulating serogroups, existing vaccine policies, cost-effectiveness, and procurement conditions. The new indication expands the options available to public health authorities, but whether vaccination coverage increases and the disease burden declines will still depend on subsequent national policies and real-world monitoring.