Factors affecting immunization coverage levels in a district of India.
Immunization coverage is measured to assess the performance of the Expanded Programme on Immunization. In 1988 we conducted a coverage survey among 12-23 month-old children in the North Arcot District (population 5,007,746) in southern India. In each of the 12 towns a 30-cluster sample survey was conducted. In the 35 rural blocks with 1590 panchayats, 159 were selected systematically and all children (n = 7300) were surveyed. In the towns, coverage ranged for measles vaccine from 29 to 53%, BCG from 65 to 91% and OPV and DPT third dose from just over 60% to just over 80%. In the rural areas, coverage ranged for measles vaccine from 10.8 to 19.3%, BCG 25.1-34.1%, DPT third dose 42.2-50.4% and OPV third dose 39.6-48%. In the towns, 25, 66, 67 and 59% of BCG, DPT, OPV and measles vaccines had been provided by private agencies showing that availability of vaccines throughout the week and easy access even in payment terms played an important role in achieving higher levels of coverage compared with rural areas where all vaccines are given by Government agencies, free of charge. In the rural areas, significantly large variations in coverage were seen among panchayats--large and peri-urban panchayats had significantly better coverage than small and more rural panchayats. Within any given block (the population unit consisting of 30-40 panchayats served by a Primary Health Centre), there were large variations in the levels of immunization coverage between panchayats.(ABSTRACT TRUNCATED AT 250 WORDS)