Menactra, a vaccine against meningococcal disease that is already approved for use in people aged two to 55 years old, has now been approved for children as young as nine months old by the US Food and Drug Administration (FDA).

Menactra was examined in four trials, the results of which showed that the vaccine produces antibodies in the blood that are protective against the disease.

Neisseria meningitidis, which is responsible for causing meningococcal disease, infects the bloodstream and the lining of the brain and spinal cord.

Meningococcal disease is dangerous as it progresses rapidly and can cause death within hours. People with the infection can also suffer from brain damage or loss of limbs or hearing.

FDA Center for Biologics Evaluation and Research director Karen Midthun said that the highest rate of meningococcal disease is seen in children below one year of age.

In trials, children between nine months and a year old were given a two-dose series beginning at nine months old, three months apart, and showed adverse affects such as injection-site tenderness and irritability.