High HIV-1 plasma viral loads (PVLs) in sub-Saharan Africa, partly because of high rates of coinfection, may have been one of the drivers of the "explosive" epidemics seen in that region. Using a previously published framework of infectiousness and survival, we estimate the excess onward HIV-1 transmission events (secondary infections) resulting from coinfection-induced changes in PVL during asymptomatic HIV-1 infection. For every 100 HIV-infected people, each suffering 1 episode of tuberculosis infection, there are 4.9 (2.7th-97.5th percentile: 0.2-21.5) excess onward HIV-1 transmission events attributable to this coinfection. Other estimates are malaria 0.4 (0.0-2.0), soil-transmitted helminths 3.1 (0.1-14.9), schistosomiasis 8.5 (0.2-38.6), filariasis 13.3 (0.3-89.2), syphilis 0.1 (0.0-1.6), herpes simplex virus 4.0 (0.0-24.2), and gonorrhea 2.1 (0.1-8.0) transmissions. If these higher PVLs confer a shorter life expectancy and higher infectiousness, then their impact on transmission is, in general, reduced. For most HIV-1 coinfections, the duration of a single infection is too short and/or the associated PVL elevation is too modest to contribute substantially to onward HIV-1 transmission.

Original publication




Journal article


Journal of acquired immune deficiency syndromes (1999)

Publication Date





594 - 598


*Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom; †Mathematics Institute, University of Warwick, Coventry, United Kingdom; ‡School of Life Sciences, University of Warwick, Coventry, United Kingdom; and §Department of Clinical Sciences, Liverpool School of Hygiene and Tropical Medicine, Liverpool, United Kingdom.


Humans, HIV-1, Bacterial Infections, HIV Infections, Parasitic Diseases, Viral Load, Adult, Africa South of the Sahara, Female, Male, Asymptomatic Infections, Coinfection