The effect of neutralizing antibodies (NAb) is also unknown, but it has been shown that individuals with HIV tend not to have a NAb response prior to superinfection.
Immune responses to initial infection with a particular strain of HIV do not provide protection against superinfection with a different strain. It is unknown what aspects of the natural immune response to HIV may protect someone from superinfection, but it has been shown that cytotoxic lymphocyte responses do not seem to be protective. Thus, superinfection occurs after an immune response to the initial infection has already been established. Ī study conducted in Kenya in 2007 shows that superinfection tends to occur during the course of the initial infection, that is during acute infection, or 1–5 years after initial infection, but not during the latency period. Infection with a second strain after seroconversion is known as superinfection. If a person is infected with a second virus before seroconversion to the first virus has taken place, it is termed a dual infection. Further research from The Journal of Infectious Diseases indicates that there have been 16 documented cases of superinfection since 2002. Research from Uganda published in 2012 indicates that HIV superinfection among HIV-infected individuals within a general population remains unknown. Cases have been reported globally and studies have shown the incidence rate to be 0–7.7% per year. These include sharing needles and forgoing condoms with HIV-positive sexual partners. People with HIV risk superinfection by the same actions that would place a non-infected person at risk of acquiring HIV.
HIV superinfection may be interclade, where the second infecting virus is phylogenetically distinct from the initial virus, or intraclade, where the two strains are monophyletic. These can form a recombinant strain that co-exists with the strain from the initial infection, as well from reinfection with a new virus strain, and may cause more rapid disease progression or carry multiple resistances to certain HIV medications. HIV superinfection (also called HIV reinfection or SuperAIDS) is a condition in which a person with an established human immunodeficiency virus infection acquires a second strain of HIV, often of a different subtype.