Researchers from the London School of Hygiene and Tropical Medicine have suggested that half of tuberculosis (TB) transmission occurs before individuals will even access care under existing TB care policies.

This investigation suggests that one in two individuals with subclinical TB, who are likely infectious but are not aware of symptoms, will not progress to disease severe enough to seek care.

Research presented at The International Union Against TB and Lung Disease’s World Conference on Lung Health revealed how new insights into TB highlight the weakness of current policies designed to eradicate the disease, where individuals need to report symptoms in a clinic before receiving care.

The amount of transmission missed was reduced to a third if the study assumed a lower relative infectiousness for subclinical TB. The study, which used a deterministic modelling framework based on 1,000 cohorts of 10,000 individuals, found that 93.5% of TB-infected individuals will not contribute to transmission within 10 years of MTB infection.

At The Union World Conference, tuberculosis experts also presented how active case finding (ACF) could reduce the 52,000 TB cases in Cambodia, of which nearly 50% go undiagnosed. With this figure often higher in minority and hard-to-reach communities, scientists stressed the importance of focusing ACF efforts in these areas.

Researchers conducted mobile case findings across 26 remote communities, which resulted in over 8,000 patients being screened. More than 5% of these people were diagnosed with TB – with 321 TB patients receiving treatment that they would not have otherwise, constituting an increased detection of 370%.

These results demonstrated the positive impact of adopting a policy of ACF in reducing transmission of TB within the community, coupled with widening invaluable access to diagnostic facilities.

Children and adolescents experience a disproportionate burden of TB. The WHO recently released its Global Tuberculosis Report, which highlighted that an estimated 1.25 million children and young adolescents fell ill with TB in 2022, making up 12% of the global TB burden.

The Union World Conference on Lung Health (from 15 to 18 November in Paris) is convened by the International Union Against Tuberculosis and Lung Disease, the world’s first global health organisation, committed to eradicating tuberculosis and lung disease.