Epidemiological evaluation of oral polio vaccine efficacy in Delhi.

Forty seven cases of poliomyelitis and 94 controls were studied for immunization status. Unmatched analysis with one control per case and two controls per case was done to find out the ratio of the odds of immunization in diseased individuals as compared with the nondiseased (odds ratio). This ratio (OR) was used further to calculate oral polio vaccine efficacy. OPV efficacy was found to be 93% with 95% confidence limits of 75-98%.

Prevalence of high risk children under five--a study in rural Delhi.

678 under five children were surveyed in village Shahbad Mohammadpur, Delhi. Two weeks morbidity was also recorded. 47.9 per cent children had one or more risk factors studied. Significantly more female children (54.1 per cent) were at risk than male children (43.3 per cent). 433 risk factors were observed in 325 at risk children. Majority of them had one or two risk factors. Birth interval less than two years and malnutrition were most frequent risk factors. At risk children suffered significantly more than not at risk (21.2 per cent vs 14.4 per cent). The results confirmed the validity of the risk factors considered for the study.

Field evaluation of measles vaccine efficacy in New Seemapuri, Shahdara Zone-Delhi during 1990.

A field evaluation of measles vaccine efficacy was undertaken in resettlement colonies in New Seemapuri, Shahdara Zone, Delhi, having an estimated population of 20,500 by case-reference method. The standard 30 cluster sampling technique was adopted and 261 measles vaccinated children were matched with 545 measles non-vaccinated children. The attack rate of measles was found to be 4.2 and 30.3 per cent in measles vaccinated and non-vaccinated children respectively, which is statistically highly significant (P less than 0.001). The relative risk of developing measles in non-vaccinated child is seven times more as compared to a vaccinated child. Vaccine efficacy (V.E.) evaluated by different epidemiological and laboratory methods was found to be 86.1 per cent +/- 11 at P = 0.05. Further, a large scale study on measles V.E. is recommended in different parts of the country by case-reference method, as it is found to be simple, reproducible and easy to undertake in a field situation.

Epidemiology of measles--a thirteen years prospective study in a village.

A prospective study on measles was undertaken during 1974 to 1986 in Hiramanpur village, Varanasi having an initial population of 1538 which rose to 2101 in 1986 enabling to register a total of 23,221 (all population) person years of observation and a total of 9191 (0-14 years) person years of observation. The entire population was covered regularly through domicilliary visits by trained para-medical personnel under direct supervision of medical officers. All cases were verified by doctors. A total of 411 measles cases were detected, which gave average annual incidence rates of 17.7 and 44.7 per thousand population and per thousand children (0-14 yrs), respectively. The maximum number of cases occurred in Ist quarter of the year (69.7 per cent). The Kolmogorov-Smirnov Statistical method validated the seasonal character of the disease (Vn = 5.18, p less than 0.01). The maximum measles cases occurred in children 1-4 yrs (57.4 per cent). Males (54.9 per cent) were affected slightly more than females (45.1 per cent). A total of 246 (59.9 per cent) cases developed complications. The most frequent was respiratory infections (42.2 per cent) followed by infection of gastrointestinal system (32.2 per cent). The complication rates were found higher in infants and older children (greater than 5 yrs.) in both the sexes. Three-fourth of the cases did not get any treatment. The overall case-fatality rate was 2.2 per cent. Females had higher rate (3.3 per cent) than males (1.3 per cent) and the highest case fatality rate was observed in infants, particularly in females.