Abstract
Background
There are large knowledge gaps on the transmission dynamics of Mycobacterium tuberculosis in settings where both tuberculosis and HIV are endemic. We aimed to assess the infectiousness of tuberculosis patients coinfected with HIV.
Methods
We systematically searched for studies of contacts of both HIV-positive and negative tuberculosis index cases. Our primary outcome was Mycobacterium tuberculosis infection in contacts. Data on sputum smear and lung cavitation status of index cases was extracted from each study to assess effect modification. Secondary outcomes included prevalent tuberculosis and HIV in contacts of HIV-positive and negative index cases.
Results
Of 5,255 original citations identified, 32 studies met inclusion criteria including 25 studies investigating M. tuberculosis infection (Nparticipants=36,893), 13 on tuberculosis (Nparticipants=18,853), and 12 on HIV positivity (Nparticipants=18,424). Risk of M. tuberculosis infection was lower in contacts of HIV-positive index cases (Odds Ratio [OR], 0.67, 95% CI, 0.58–0.77) but was heterogeneous (I2=75.1%). Two factors modified this relationship: the lung cavitary status of the index case and immunosuppression (measured through CD4 counts or HIV or AIDS diagnoses) among index patients living with HIV. Rates of HIV were consistently higher in contacts of coinfected index cases (OR, 4.9, 95% CI, 3.0–8.0). This was modified by whether the study was in sub-Saharan Africa (OR, 2.8, 1.6–4.9) or in another global region (OR, 9.8, 5.9–16.3).
Conclusions
Tuberculosis patients coinfected with HIV are less infectious than HIV-uninfected cases when they have severe immunosuppression or paucibacillary disease. Contacts of coinfected index cases are almost five times more likely to also have HIV.
Meta-analysis of human gene expression in response to Mycobacterium tuberculosis infection reveals potential therapeutic targets
