The fourth-round vaccination campaign of the 13th National Day of Immunization (NDI) will be held in Bangladesh on August 6.

On the day, two drops of polio vaccine will be administered to all children aged zero to five years as an antidote to the deadly disease.

Children either given or not given the vaccine in the previous rounds could be fed with the vaccine in the fourth round, a government announcement say in Dhaka on Monday.

"All the vaccination centers across the country will be available for vaccination. Parents can get their children vaccinated at airports, rail-stations, bus terminals, ferry ghats and launch terminals during travel time," the announcement adds.

The 1st round of 13th NDI was observed on April 16, the 2nd on May 13 and the third on June 11.