May 30, 2025 – The FDA has approved the first-ever meningococcal vaccine for babies as young as 6 weeks old.
Sanofi Pasteur’s quadrivalent MenQuadfi shot was first cleared in 2020 for adults and children ages 2 years or older. It protects against invasive meningococcal disease (IMD) caused by the four most common strains of meningococcal bacteria (Neisseria meningitidis): A, C, W, and Y.
IMD is rare but can turn deadly within hours, causing brain swelling, blood infection, or death. Even with fast treatment, 10% to15% of patients don’t survive, and many survivors face serious complications such as hearing loss or nerve problems, according to the CDC. Infants younger than 1 year old are at the highest risk, followed by children up to 4 years old. Teens and young adults (ages 16 to 23) are at higher risk, by being in college dorms, kissing, and sharing drinks. Early vaccination is key to preventing infection and long-term harm.
The approval was based on positive results from clinical studies involving 4,273 infants ages 6 weeks to 23 months, who received at least one dose of either a four-dose or two-dose series of MenQuadfi. After each shot, they were monitored for immediate reaction, and parents worked closely with doctors during follow-up visits. The results showed the vaccine was effective, safe, and well-tolerated in the newly approved age group, with no new safety concerns reported.
Infants can be given the shot at 6 weeks old, with four doses given at 2, 4, 6, and between 12 and 18 months. Babies ages 6 to 23 months will get two doses, with the second given in their second year and at least three months after the first dose, whereas anyone age 2 years or older only needs one dose. A single booster shot of MenQuadfi can be given to people ages 13 years or older who are at a continued risk of IMD if it’s been at least three years since their last meningococcal vaccine. MenQuadfi doesn’t protect against strain B of N meningitidis.
Common side effects of MenQuadfi in infants ages 6 weeks to below 2 years include soreness, redness, or swelling where the needle went in, crankiness or fussiness, unusual crying, sleepiness, loss of appetite, fever, and sometimes vomiting. Older people may have pain where the needle went in, muscle aches, headaches, and tiredness.