Breaking the paradigm: Optimized Case Finding multiplies tuberculosis detection among key populations in Ukraine.

Introduction: In 2018, there were 3 million "missed" tuberculosis (TB) cases globally, much of which was disproportionally concentrated among key populations. To enhance TB case-finding, an Optimized Case Finding (OCF) strategy involving all contacts within the social network of an index TB case was introduced in five regions of Ukraine. We assessed TB detection and linkage to TB treatment using OCF in key populations.

Methodology: A cohort study using routine program data (July 2018 - March 2020). OCF empowers the index TB case to identify and refer up to eight close contacts within his/her social network for TB investigations.

Results: Of 726 index TB cases in key populations, 6,998 close contacts were referred for TB investigations and 275 were diagnosed with TB (183 drug-sensitive and 92 drug-resistant TB). The TB case detection rate was 3,930/100,000 and the Numbers Needed to Investigate to detect one TB case was 25. TB was most frequent among people who inject drugs and homeless groups. Compared to TB detection using routine household case finding within the general population (1,090/100,000), OCF was 3.6-fold more effective and when compared to passive case finding in the general population (60/100,000), OCF was 66 times more effective. 99% (273) of TB patients were linked to care and initiated TB treatment.

Conclusions: The OCF strategy among key populations is very effective in identifying TB cases and involving them for treatment through the recruitment of the contacts from the risk social networks. We advocate to scale-up this case finding strategy in Ukraine and beyond.