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 Ndoe,
If you don’t want to transmit HIV to your partner, and if you want kids you’ll need to be on meds. Though this may be scary, (which is normal) meds really are the best thing for you. They allow you to control your HIV, and they stop transmission. Being on meds is also better for your long term health.
For more info about starting, please see here:
http://i-base.info/guides/starting
Hi Lisa
In 2013 I found that I’m HIV positive and I was shocked and from there I never took meds and I have not got sick unusual and now I’m married and my partner is negative I don’t want him to be HIV positive and i need kids I don’t know what to do.
Hi Muka,
If you want to control your HIV you’ll need to be on meds. This is because only meds can control a persons HIV. For more about treatment please see here:
http://i-base.info/guides/starting
The World Health Organisation also recommend that everyone is on meds. This is regardless of their CD4 count.
I’ve just been diagnosed with HIV. Do I really need to take ARVs? Can’t I just have a balanced diet?
Hi Antronique,
What your doctor has told you is wrong. There is no cure for HIV. However, modern day ARVs are very effective, so much so that your life expectancy is likely to be the same as it would have been had you not have contracted HIV. This is great news for people who are living with HIV.
Its important that you take your meds daily. Being on medication also means that once your viral load becomes undetectable you won’t be able to transmit HIV to a sexual partner.
If you’d like more info, please email us.
i just realize i had hiv-1!! at first i was depressed and crying like oh lord im gone die and im not gone see my babygirl make it!!!! but my doctor told me, that it was cureable!!! just long as i take my meds and do as im instructed!!!!
Hi Cat,
Thanks for sharing your experience with us. And good luck with having some more kids.
i hope people realise thats there is no point in feeling depressed cos you are hiv positive i am and my husband isnt apart from being sick once that was my fault cos i got fed up of taking my arvs i was moving countries an i was fed up psychologically for bein defined as a victim since i hadnt been ill for ages and my daughter and husband are negative i was like wtf i have had enough anyway to cut a long story short i didnt take my arvs and developed pml jeez now that was a wake up call i moved countries again with hubby went straight to the dr was put on triumeq i was just lucky i didnt die never again with triumeq my life is better only one pill plus family support i am blessed. i have resigned myself to the truth i wil take the triumeq untill i leave this life but i know before i go i will get me some more kids hiv is simply an illness that can be managed nowadays
Hi Karen,
Feeling depressed and upset is common when people are diagnosed. As too is blaming other people.
Though I don’t know how you contracted HIV, its important to understand that most people don’t just go around ‘spreading’ the illness around. Quit often people don’t know they are positive.
Yes, this may be hard time. But HIV is a very manageable health condition. The treatment is excellent, and it allows people to lead normal lives. This isn’t to say that there won’t be changes because there might be. What might help is if you got some support.
Recently I have deducted hiv 1, also I started art now my life gone all my Happyness. Why peoples want to spread HIV virus I don’t know , they positive why gives to others also…