From the Guidelines
HIV-1 is significantly more prevalent than HIV-2, with HIV-2 being extremely rare in the United States.
Prevalence of HIV-1 and HIV-2
- The prevalence of HIV-2 is extremely low in the United States, and the CDC does not recommend routine testing for HIV-2 in settings other than blood centers, unless demographic or behavioral information indicates that HIV-2 infection might be present 1.
- HIV-2 is endemic in parts of West Africa, and an increased prevalence of HIV-2 has been reported in Angola, France, Mozambique, and Portugal 1.
- HIV-1 is more prevalent globally, but the exact prevalence is not specified in the provided evidence.
- Testing for HIV-2 should be conducted when there is clinical evidence or suspicion of HIV disease in the absence of a positive test for antibodies to HIV-1 1.
- The CDC recommends testing for antibodies to both HIV-1 and HIV-2 when epidemiologic risk factors for HIV-2 infection are present 1.
From the Research
Prevalence of HIV-1 and HIV-2 Infections
- The prevalence of HIV-1 is estimated to be around 37 million people globally, with 1.7 million newly acquired infections occurring on average each year 2.
- HIV-2 is largely confined to West Africa, with a lower prevalence compared to HIV-1 3, 4.
- A study in West African female prostitutes found that the prevalence of HIV-2 ranged from 10.0% to 38.1%, while the prevalence of HIV-1 ranged from 0.4% to 4.1% 5.
Geographical Distribution
- HIV-1 is found worldwide, while HIV-2 is mainly found in West Africa 3, 4.
- A study found that HIV-2 is endemic in some countries in West Africa, but has a lower prevalence in industrialized countries 6.
Risk Factors
- Increased years of sexual activity and a history of scarification were associated with HIV-2 seropositivity in female prostitutes in Dakar, Senegal 5.
- HIV-1 seroprevalence was associated with a shorter duration of prostitution and a history of hospitalization in female prostitutes in Dakar, Senegal 5.
- A history of never using condoms was associated with HIV-2 seroprevalence in female prostitutes in Kaolack, Senegal 5.
Comparison of HIV-1 and HIV-2
- HIV-1 and HIV-2 share many similarities, but HIV-2 is characterized by lower transmissibility and reduced likelihood of progression to AIDS 3.
- Plasma viral loads are consistently lower in HIV-2, and average levels of immune activation are also lower in HIV-2 3.
- The immune response to HIV-2 appears more protective against disease progression, suggesting that pivotal immune factors limit viral pathology 3.