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A Case Worth Noting: HIV Superinfection

A well-documented case of human HIV superinfection underscores the importance of practicing safe sex and raises questions for vaccine development.

Is it possible for an HIV-positive individual to be infected with a second HIV strain? The answer to this question used to be "probably not." The proposed explanation was "superinfection immunity," generated as part of the host response to initial viral infection, which protects against subsequent exposures. This explanation has been challenged by some incompletely documented reports of superinfection in humans and by experimental evidence in primate models. Now, Jost and colleagues report a convincing and well-documented case of HIV superinfection in a man exposed to genetically distinct strains of HIV.

HIV seroconversion with HIV subtype AE was diagnosed in this patient in November 1998. He was effectively treated with combination antiretroviral therapy and achieved HIV RNA levels <50 copies/mL. After he discontinued therapy in January 2001, his viral load rebounded to 80,000 HIV RNA copies/mL and then leveled off at about 20,000 copies/mL. In April, his viral load surged to 400,000 copies/mL, and he developed fever and fatigue. Genetic studies revealed circulating HIV, subtype B, which is common in Brazil and consistent with his recent unprotected sexual exposures there. No evidence could be found that he had been coinfected with subtype B at the time of his initial infection, which suggested that superinfection had occurred in early 2001.

Comment: We now know that HIV superinfection is possible in humans. The frequency of this phenomenon and the implications for vaccine development are 2 critical questions that demand urgent attention. Equally important is the message that HIV-positive individuals must practice safe sex to protect themselves and others from new infection.

— Diane V. Havlir, MD

Published in Journal Watch Infectious Diseases September 20, 2002

Citation(s):

Jost S et al. A patient with HIV-1 superinfection. N Engl J Med 2002 Sep 5; 347:731-6.

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• Medline abstract (Free)

Goulder PJR and Walker BD. HIV-1 superinfection -- A word of caution. N Engl J Med 2002 Sep 5; 347:756-8.

• Original article (Subscription may be required)
• Medline abstract (Free)