At least 14 children have been killed so far following an outbreak of measles in Nigeria’s southeastern state of Anambra, local authorities said on Wednesday.

The outbreak has spread to at least nine local government areas of the state, where over 414 cases have been confirmed since March, Afam Obidike, the commissioner for health in Anambra, said to reporters in Awka, the state’s capital.

Obidike said the case fatality rate of the outbreak is currently at 48 percent.

To tackle the outbreak, a total of 19,609 unvaccinated children from age zero to 59 months have been vaccinated so far, the official said, adding the routine immunization of children has been reactivated in the state to prevent future outbreaks.

Measles is a viral infection common among children under five years but easily preventable through the administration of doses of vaccine.

The disease spreads through the air by respiratory droplets produced from coughing or sneezing.