At what age is the third dose of inactivated polio vaccine typically administered?

The third dose of the inactivated polio vaccine (IPV) is typically administered at 6-18 months of age, aligning with the routine immunization schedule recommended by health authorities. This timing is designed to boost the child's immunity as part of a series of vaccinations, which generally begin at 2 months of age with the first dose and continue at intervals to ensure optimal protection against polio.

The immune system of children is still developing in the first few years of life, and administering vaccines at the correct intervals helps to establish robust immunity. The second dose is usually given at 4 months, making the 18-month mark for the third dose a strategic point in their development, allowing for an effective immunological response.

The options of 6 months, 4 months, and 2 months represent other doses in the vaccination schedule rather than the third dose itself. The second dose at 4 months and the first dose at 2 months are critical in building the child's immunity, but they do not correspond with the timing of the third dose. Therefore, 18 months is identified as the appropriate age for administering the third dose of the inactivated polio vaccine in accordance with the established immunization schedule.