Email 694: Two Strains of HIV

Posted by Pozziepinoy on 7:59 AM

Hi pozziepinoy,

I tested reactive both to HIV-1 and HIV-2 strains. What does that imply to my treatment? Would I be recovering slower with meds? Are they going to prescribe me with more ARVs than the usual? And in general, what's the difference of having both strains and having just one?

Thanks so much for your blog. It allowed me to look much far ahead even before learning that I had the virus so I didn't have any down reactions upon knowing.



POZZIEPINOY’S RESPONSE


Hi.

Thank you for your email. Thank you for the kind words about the blog.

To give factual information, I researched about it and this is what I found:



HIV is a highly variable virus which mutates very readily. This means there are many different strains of HIV, even within the body of a single infected person.
Based on genetic similarities, the numerous virus strains may be classified into types, groups and subtypes.

What’s the Difference Between HIV-1 and HIV-2?
There are two types of HIV: HIV-1 and HIV-2. Both types are transmitted by sexual contact, through blood, and from mother to child, and they appear to cause clinically indistinguishable AIDS. However, it seems that HIV-2 is less easily transmitted, and the period between initial infection and illness is longer in the case of HIV-2.
Worldwide, the predominant virus is HIV-1, and generally when people refer to HIV without specifying the type of virus they will be referring to HIV-1. The relatively uncommon HIV-2 type is concentrated in West Africa and is rarely found elsewhere.

Is it Possible to be infected More than Once?

Until about 1994, it was generally thought that individuals do not become infected with multiple distinct HIV-1 strains. Since then, many cases of people coinfected with two or more strains have been documented.
All cases of coinfection were once assumed to be the result of people being exposed to the different strains more or less simultaneously, before their immune systems had had a chance to react. However, it is now thought that "superinfection" is also occurring. In these cases, the second infection occurred several months after the first. It would appear that the body's immune response to the first virus is sometimes not enough to prevent infection with a second strain, especially with a virus belonging to a different subtype. It is not yet known how commonly superinfection occurs, or whether it can take place only in special circumstances.

What are the treatment Implications?

Although most current HIV-1 antiretroviral drugs were designed for use against subtype B, there is no compelling evidence that they are any less effective against other subtypes. Nevertheless, some subtypes may be more likely to develop resistance to certain drugs, and the types of mutations associated with resistance may vary. This is an important subject for future research.
The effectiveness of HIV-1 treatment is monitored using viral load tests. It has been demonstrated that some viral load tests are sensitive only to subtype B and can produce a significant underestimate of viral load if used to process other strains.The latest tests do claim to produce accurate results for most Group M subtypes, though not necessarily for Group O. It is important that health workers and patients are aware of the subtype/CRF they are testing for and of the limitations of the test they are applying.
Not all of the drugs used to treat HIV-1 infection are as effective against HIV-2. In particular, HIV-2 has a natural resistance to NNRTI antiretroviral drugs and they are therefore not recommended. As yet there is no FDA-licensed viral load test for HIV-2 and those designed for HIV-1 are not reliable for monitoring the other type. Instead, response to treatment may be monitored by following CD4+ T-cell counts and indicators of immune system deterioration. More research and clinical experience is needed to determine the most effective treatment for HIV-2.






"WE ARE ALL IN THIS TOGETHER.
NO PLHIV is alone with his or her struggle with HIV!"

-Pozziepinoy-



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