BCG coverage and the annual risk of tuberculosis infection over a 14-year period in the Philippines assessed from the Nationwide Prevalence Surveys

SETTING: A prevalence survey of tuberculosis (TB) infection was undertaken in the Philippines, a developing country in the Western Pacific region. OBJECTIVE: To determine the bacille Calmette Guerin (BCG) vaccination rate, the prevalence of TB infection and the annual risk of TB infection (ARTI). METHODS: A nationwide stratified multi-stage cluster survey of 21 960 indiv iduals. BCG scar verification and tuberculin test were performed on those a ged greater than or equal to 2 months. The ARTI was calculated using the pr evalence rates of TB infection in children aged 5-9 years. RESULTS: BCG scars were noted in 66% of the study population. The prevalenc e of TB infection was 63.4% among unvaccinated individuals. The prevalence rate was higher in males in both urban and rural areas. With both sexes com bined, urban and rural communities had similar prevalence rates. In childre n aged 5-9 years, the prevalence rate was 16.1% (males 17.4%, females 14.9% ), corresponding to an ARTI of 2.3% (males 2.5%, females 2.1%). CONCLUSION: BCG coverage increased substantially between 1981-1983 and 1997 . The ARTI, however, was virtually unchanged, indicating that morbidity due to TB continued to be high.