Nearly all of the vaccine used in the global campaign is the oral live virus form associated with Albert Sabin. The advantages of oral polio vaccine are that the drops are much cheaper than injected vaccine and do not require highly trained medical personnel to administer every dose. One doctor or nurse can supervise many volunteers, making it possible to carry out massive vaccinations. These countrywide campaigns are called National Immunization Days and occur on two days about six weeks apart. On a single day, January 21, 2001, 150 million children under five years of age in India were immunized.
During a National Immunization Day, vaccinators mark the left pinky finger of every child with indelible ink, to keep track of who has received the vaccine drops. In Brazil, an imaginary character, “Little Drop,” is used to ease children’s fears about vaccination.
At times, National Immunization Days have occurred during civil wars, making the vaccinators’ work dangerous. This happened in Peru, El Salvador, and Angola. In each case, cease-fires, called Days of Tranquility, were negotiated to allow the vaccinators safe passage.