BCG Efficacy in Children Aged 1-7 years In A rural Area in East Nile Province

Abstract

Tuberculosis remains the most common single cause of death. Although BCG vaccination was introduced in 1920, yet its protective role remains contraversial. This study was conducted in three rural areas in East Nile Province, during the period from 1st of June to 31ist of August 2003. It was community-based study done through house-to-house survey. The main objectives of this study were to evaluate the efficacy of BCG vaccine and to correlate the efficacy to presence or absence of scar and some social factors. A total of 398 children (50.3% Males and 49.7% Females) aged 12 months to seven years were studied. All relevant informations on medical, social history, history of BCG vaccination including age of vaccination, symptoms suggestive of tuberculosis, physical examination including checking BCG scar and measurement of scar size, were noted on a pre-coded questionnaire. Mantoux test was done and the induration was measured 72 hours later. The study showed that the predominant age group was 12-36 months, which represents 42.7% of the study population; 95% were BCG vaccinated (documented by BCG scar, vaccination card or both). 73.9% of them were vaccinated in the first 3 months of age and 72% of the vaccinated had BCG scar, 39.1% of the scars measured from 2 to 5 mm, reflecting good efficacy of BCG vaccine given.68.85% of children 8 showed tuberculin reaction less than 5mm while only 2.5% showed reaction more than 10 mm. It was found that there is significant association between the size of the scar and tuberculin measurement supporting the fact that BCG scar is a strong indicator for vaccine efficacy. During the study 2(0.5%) cases of TB were diagnosed, their ages were 14 and 18 months and both were BCG vaccinated as documented by BCG scar (in the range of 2-5 mm), infected TB cases represent (0.1%) of the vaccinated children, which reflect high protection although the number of non vaccinated group was small in comparison with the vaccinated group. Social factors such as family income and number of persons per room did not significantly affect TB infection. The study concluded that BCG vaccination was efficient reflected in the good immunity documented by BCG scar and just (0.1%) TB cases among the vaccinated group.