Strengthening TB surveillance system in India: Way forward for improving estimates of TB incidence

One of the key indicators used under India’s TB control program is the DOTS case detection rate of new sputum smear positive TB whose estimates in India are based on incidence estimates derived from Styblo’s rule. Styblo’s rule was formulated in an era without well-established tuberculosis control program, effective tuberculosis drugs, and emergence of TB-HIV coinfection, so today it does not reflect the true incidence of TB. Considering various loopholes in different methods of measurement of incidence (prevalence surveys of disease/ infection, vital registration system and Styblo’s rule), strengthening of existing surveillance system is the best tool to obtain correct estimates of tuberculosis incidence in India.