Coinfection does not appear to augment TB infectivity

TB from patients coinfected with HIV is not usually more infective than TB from HIV-negative patients, according to researchers in Italy.

Mario Cruciani and colleagues at the Center for Preventive Medicine-HIV Screening Center in Verona and the University of Genoa’s Institute of Infectious Diseases conducted a retrospective study to determine -if the relative infectiousness of patients with tuberculosis is enhanced by coinfection with HIV. –

Researchers found no evidence that exposure to HIV patients with drug-sensitive TB was more dangerous than exposure to otherwise healthy TB patients. Cruciani and coworkers reviewed the results of two sets of studies. Data from the first set, comprising six studies of more than 1,200 TB-exposed health care workers, showed that the rate of positive tuberculin skin tests was virtually identical between workers exposed to HIV-positive or HIV-negative patients, according to their report.

Similar conclusions were drawn after examining the second group of 11 studies, which included data from more than 10,000 workers who contacted TB patients at home. In fact, researchers found that skin test positivity was actually less prevalent among health care workers in the cohort who contacted HIV-positive TB patients. -These data suggest that tuberculosis patients with HIV infection are not intrinsically more infectious to their contacts than are HIV negative tuberculosis patients, – Cruciani and coauthors concluded. The full report, -Impact of Human Immunodeficiency Virus Type 1 on Infectiousness of Tuberculosis: A Meta Analysis, – is published in Clinical Infectious Diseases, December 2001;33(11):1922-1930.