"We will undertake mass immunisation beginning on August 31 in East Khasi Hills district where there is maximum population," state nodal officer for immunisation Dr E Chyne said.
She said the mass awareness campaign was launched in Jaintia Hills and Ri-Bhoi districts, while it was being intensified in the West Khasi Hills district.
At least four persons have died due to JE in the state, while six others were being treated at different hospitals.
State Health minister A L Hek said his department was monitoring the spread of JE closely after reports of deaths even as the Chief Minister himself was reviewing the situation closely.