Question
What is the difference between HIV-1 and HIV-2?
27 September 2006. Related: All topics, Other tests.
What is the difference between HIV1 and HIV2 with regards to structure, function, occurence and survival in the environment?
Answer
HIV-1 and HIV-2 are two different viruses. HIV-1 is the main family of HIV and accounts for 95% of all infections worldwide. HIV-2 is mainly seen in a few West African countries. The spread in the rest of the world is negligible.
Although HIV-2 generally progresses more slowly than HIV-1, some HIV drugs (NNRTIs like nevirapine and efavirenz) do not work against HIV-2.
On a structural level HIV-1 and HIV-2 have important genetic differences. A technical description of the difference is that the vpu gene found in HIV-1 is replaced by the vpx gene in HIV-2. In addition, the protease enzymes from the two viruses, which are aspartic acid proteases and have been found to be essential for maturation of the infectious particle, share about 50% sequence identity.
There are, however, differences in substrate and inhibitor binding between these enzymes. Most notably between the CGP 53820 inhibitory binding.
On functional level, there is a difference between the two viruses in terms of how easy it is for the virus to infect someone. HIV-1 enters the immune system by attaching onto the CD4+ receptor found on the surface of certain white blood cells. HIV-2 has a harder time gaining such a foothold.
So HIV-2 generally progresses much more slowly, with lower viral laod and slower risk of becoming sick. However, some HIV drugs (including NNRTIs) are not active against HIV-2.
Both viruses are fragile and highly susceptible to physical and chemical agents and therefore do not survive well outside the human body. HIV in blood or sexual fluid for example is not infectious after it has been outside the body for a few minutes.
Notes: this answer was updated in January 2018.
Hi Hope,
It doesn’t mean you have AIDS. But all positive results for the rapid test need to be confirmed by a second more sensitive test. Please see this link.
Hi I had a positive result of hiv1by rapid screening is that mean I have AIDS
Hi Jessy,
This isn’t something that sounds like its related to taking ARVs. Please talk to your doctor about this.
Hi.
I discovered I was HIV 1 & HIV 2 four months ago and my CD4 counts 450 then, and I have been on medication but sometimes when I take the drug it hot my tummy. What should I do?
Hi Vanessa,
Are you HIV positive? These Q&As provide up to date information about HIV treatment (ART) for HIV positive people and family and friends. Is your question about ART for HIV2?
hello
I’m doing a presentation on HIV2 and this is not descriptive enough, I need resources!!
Hi Ary,
If you want to control your HIV then you’ll need to be on medication. When was the last time you had your CD4 count done?
Hello sir
I am hiv 2 patient last 15 years .
Presently iam good health
Till now I am don’t take any treatment can u advise me
Hi Unluckylovely,
It sounds like you may be an elite controller. Even if this is the case, its recommended that everyone who is positive should be on medication.
Hello,
I was diagnosed with HIV-2 in 2011. I have not been on any medication treatment, but have conducted my own research and purposefully looked after myself and eat the right kinds of food. My last blood test in June 2018 showed that my CD4 is now 700 which has slowly decreased from 1190 over the years. My last test also showed my viral load to be <50. Therefore my question is, how long can I go without treatment? as I am not keen on taking any ART at this moment in time. Please advise if you can. Thank you