Could ART increase the population level incidence of TB?

TL;DR

This paper examines whether widespread ART use for HIV-positive individuals could inadvertently raise overall TB incidence, considering factors like timing of ART initiation and coverage levels.

Contribution

It identifies specific conditions under which ART might increase TB incidence at the population level, highlighting the importance of early treatment and high coverage.

Findings

Early ART initiation (CD4+ > 350) prevents long-term TB incidence increase.

High ART coverage is crucial to avoid population-level TB rise.

Late ART initiation with low coverage could elevate TB incidence.

Abstract

HIV increases the likelihood that a person will develop TB. Starting them on anti-retroviral therapy (ART) reduces their risk of TB but not to the level in HIV negative people. Since HIV-positive people who are on ART can expect to live a normal life for several decades this raises the possibility that their elevated risk of infection, lasting for a long time, could lead to an increase in the population level incidence of TB. Here we investigate the conditions under which this could happen and show that provided HIV-positive people start ART when their CD4+ cell count is greater than 350/microL and that there is high coverage, ART will not lead to a long-term increase in HIV. Only if people start ART very late and there is low coverage of ART might starting people on ART increase the population level incidence of TB.