Overview of tuberculosis in Hong Kong in 2017

     The Tuberculosis and Chest Service (TB&CS) of the Public Health Services Branch of the Centre for Health Protection of the Department of Health received 4 306 tuberculosis (TB) cases (provisional figure) in 2017, representing 58 cases per 100 000 members of the population, the lowest level on record.
 
     The TB&CS of the DH announced today (June 27) the TB cases filed to DH locally as well as TB clusters in the school setting in 2017.
 
     People in the usual school age of 3 to 24 accounted for 283 cases among the notified cases in 2017. The figures for cases involving those aged 3 to 24 ranged between 250 and 350 annually in the previous three years.
 
     According to the data as of May 31 this year, there were 15 clusters of TB cases in the school setting last year. Most of them (86.7 per cent) appeared in secondary schools and tertiary institutions. The cluster sizes ranged from two to 15 cases, with a median of four cases. For clusters detailed by type of school and month in the school setting in 2017, please refer to Figures 1 and 2 in the attachment. The data has also been uploaded to the TB&CS webpage of the DH. 
 
     "As TB is an airborne disease, clustering of TB cases in the school setting occurs from time to time, often related to delayed presentation or diagnosis of the infectious source hindering early identification," a spokesman for the DH explained.
 
     The TB&CS of the DH endeavours in the monitoring of likely infectious cases in the community. The TB&CS has also prepared guidelines on handling TB cases in the school setting for reference by schools. The guidelines are available at the guideline website for more information.
 
     "Early identification of TB cases and prompt initiation of anti-TB treatment remain the mainstay of TB control. The TB&CS of the DH also conducts contact screening for the closer contacts of the index case considered infectious. The DH will continue to promote awareness of TB and its prevention in schools, the community and the health care sector so as to facilitate early identification and diagnosis to allow effective control of the disease at its source," the spokesman added.
 
     When a TB patient coughs or sneezes, small droplets containing the tubercle bacilli are generated and spread in the air. If another person breathes in these small airborne droplets, he or she may be infected with the germ. Prolonged exposure, however, is usually required for the disease to be transmitted.
 
     Despite a marked and consistent decrease in the notification rate in the past few decades, TB remains a relatively common disease in Hong Kong. In light of public concern regarding TB clusters in the school setting, data summaries will be released half-yearly starting this year.