HIV reinfection reported in 10% of couples in Zambian study

Simon Collins, HIV i-Base

A poster from C Kraft and colleagues from the Zambia Emory HIV Research Project reported on the incidence of HIV subtype C reinfection in heterosexual couples infected with genotypically different viruses.

The study aimed to see whether reinfection could be detected, together with the frequency, and any virologic consequences.

Seventeen unlinked couples were screened with a gp41-based heteroduplex mobility assay for reinfection and the results were confirmed by phylogenetic analysis of single genome amplified env genes.

Three cases of reinfection were confirmed, only two of which occurred during early infection. In one case a newly infected partner was reinfected by their chronically infected spouse, and, in the second, reinfection of the seroconverting partner resulted from a second non-spousal transmission. In the third case, reinfection in a chronically infected partner occurred during acute infection of his partner’s unlinked infection.

In two cases, reinfection was accompanied by a 10-fold increase in viral load. Phylogenetic analyses were consistent with rapid recombination between the reinfecting strains in each individual.

The authors concluded “in this retrospective study of a limited number of HIV-1 infected cohabiting couples, superinfection appears to be a frequent event (3/34).


Similar rates of reinfection have been reported in several at least one other heterosexual study, although rates in MSM are still poorly studied.

It may be important that the case reinfection during chronic infection was from a partner in acute infection when vireamia is highest.


Kraft CS et al. HIV-1 superinfection in cohabiting Zambian heterosexual couples. 48th ICAAC, 25-28 October 2008. Washington. Abstract H-4049.

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