8 ms·

Not my area of expertise but even if we can address 99% of strains, wouldn't that last 1% just take over and become the new 100% leaving us back where we starte

Not my area of expertise but even if we can address 99% of strains, wouldn't that last 1% just take over and become the new 100% leaving us back where we started? Or is the promise here that we can combine this discovery with another that solves that remaining 1%? Or, do the mutations of that last 1% make HIV less virulent or harder to transmit?

perlgeek 10y ago
> Not my area of expertise but even if we can address 99% of strains, wouldn't that last 1% just take over and become the new 100% leaving us back where we started? Not my area of expertise either, but as I understand it, it really depends on how many strains you are infected with. If it's just one, it'd reduce the infections in the next generation of patients by 99%. If the average patient had 10 strains, randomly distributed, it'd still reduce the infection rate by 90% (because there's a 10% chance of having that one resistant strain). Only if all HIV patience had all strains (and I'm pretty sure that's not the case) would it bring us back to where we started.
- dogma1138 10y ago
  You don't reduce the infection rate by 99% or by 90%, it's not even the correct term really. The transmission rate of HIV is not really dependant on the strain but on the behaviour of the affected host. Since HIV infection can be asymptomatic even for the natural life of a host the transmission rate is then dependant on the environment the social interaction of that host. A host that has unprotected sex (or any other risky activity as far as blood transmitted diseases go) and does not get tested regularly will have a considerably higher transmission rate than a host that has only protected sex and gets tested when they switch partners. Most HIV patients are infected with multiple strains, because at this point most new infections are multi-strain ones due to the lifestyle of the hosts and due to the fact that the virus can mutate in vitro. I'm also not clear how does this press release counts "strains", since it's 16 it's more than just by major types HIV-1 and HIV-2, but then it's the question of what and how they count sub groups. Most people in the west will get infected by HIV-1 Group M type B, type B itself can have several variations, and there are also host specific mutations, and if you are coinfected with another subtype you can have multiple variations of both and also recombinant (a new form made out of several types of the virus due to coinfection of a single cell) variations that may or may not be unique to each host. That said effective post infection and pre AIDS outbreak treatments can drastically reduce of new hosts that end up as transmission vectors and carriers, if HIV becomes a considerably more manageable disease that would allow most infected people to carry on with a normal lifestyle (safely have sex with a partner, and have children) once treated more people are more likely to be tested regularly. If you can also contain the disease to specific subtypes which are regionally locked as sad as it sounds you still doing quite a bit of good since now you can focus your resources on education and containment as well as further research since the transmission rates between say interveinal drug users in Berlin are considerably higher than between a sex worker in nairobi and the same drug users.
kendallpark 10y ago
It's all a statistics game. If you can vaccinate against 99% of current strains, you can severely stunt the spread of the virus with its current strain distribution. Combine this with adequate awareness about general prevention methods (safe sex practices) and you have a shot at severely reducing the incidence of the virus so that its numbers are small enough to control. New HIV infections are actually on the decline worldwide thanks to community awareness and ART meds that decrease the chances of spread. We've been able to eradicate or nearly eradicate several viruses from the planet. It starts with getting them down to manageable numbers, then addressing every outbreak. (Granted, HIV is not quite an analagous in terms of spread to viruses like smallpox.) https://en.wikipedia.org/wiki/Eradication_of_infectious_diseases#Eradicated https://en.wikipedia.org/wiki/Eradication_of_infectious_dise...
- branchless 10y ago
  If spread is reducing is it viable to simply manage this out over the long term? Or is that unrealistic.
  - kendallpark 10y ago
    The difficulty is that once you're a carrier, you're always a carrier. With modern ART these people can be expected to live long lives. ART decreases the odds of transmission, but not everyone is compliant with their medications. Reducing the spread is one piece of the puzzle. The only way we've managed to "cure" HIV is through a bone marrow transplantation from a donor that have a mutant CCR5 receptor (which the HIV virus needs infect T-cells). I think that reducing the spread alone still could get us to a point where we "manage this out over the long term" as you say. Say you're a person with many sexual partners that has say a 1 out of 100 chance of sleeping with someone infected with HIV on a given day. Say there's a 1 in 10 chance that encounter will lead to transmission of the virus. (These aren't like factual numbers, just examples). That's still a 1 in 1,000 chance per encounter, so it adds up over time. After 1000 encounters chances are you've contracted HIV. But say you're vaccinated against 99% of the serotypes. That reduces your chance per encounter to 1 in 100,000. Even after 1000 encounters your chance of contracting HIV is 1 in 100. Not terrible.
orblivion 10y ago
It would seem to me that this concept of the strongest strain taking over only would happen if there were some sort of competition for resources. If you have one strain of HIV it seems weird to think that it would stop you from getting another strain and then passing both on. But "not my area of expertise" either.
- nonbel 10y ago
  First, it seems very difficult (for a virus) to transmit HIV via vaginal intercourse[1]. Second, most infections appear to start from a single virus,[2] despite the huge genetic diversity of intrapatient HIV that supposedly makes it hard to treat[3]. That means most of the strains found within one person never get transmitted. How do you manage to transmit HIV contaminated fluids but only one infection occurs in the receiving person? Very strange. Another strange thing, it does not seem all that difficult (relatively) for interspecies transmission to occur: "Scientists have now documented that the SIV virus has jumped from monkeys or apes into humans at least 13 separate times!"[4] Perhaps those transmissions are due to self-injury while cutting infected meat, etc. The vagina is tissue that expects the presence of foreign human cells, and so has defenses against them. Anal sex, injections, etc are a different story. To me it sounds like an entire cell gets transmitted. [1] http://m.jid.oxfordjournals.org/content/191/9/1403.full http://m.jid.oxfordjournals.org/content/191/9/1403.full [2] http://www.ncbi.nlm.nih.gov/m/pubmed/18490657/ http://www.ncbi.nlm.nih.gov/m/pubmed/18490657/ [3] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2614444/ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2614444/ [4] http://evolution.berkeley.edu/evolibrary/news/081101_hivorigins http://evolution.berkeley.edu/evolibrary/news/081101_hivorig... EDIT: Another possibility is that the vast majority of these variants found floating free in the blood are non-functional and serve as chaff to confuse the immune system.
- Fomite 10y ago
  The concept is known as "vaccine escape" and is present in some viral diseases but not others. I confess I don't know how between-strain viral dynamics of HIV work, but it was definitely a concern for HPV, though it does not appear to be happening.
- ufo 10y ago
akiselev 10y ago
That unaffected 1% will still be limited by the rate of transmission which has been falling globally for decades because of growing access to birth control and antivirals, anonymous needle exchanges, and education. HIV isn't like a bacteria that grows out of control because the probability of transmission is highly dependent on the viral load, which varies significantly over the different strains and patients' lifetimes as their immune systems battle the virus. Even if eliminating 99% of strains only cures 50% of patients, those cured would have to have sexual or blood contact with the remaining 50% in order to get reinfected with the resistant strains. HIV is a very expensive disease to treat and since it's no longer a death sentence, a significant amount of resources go towards a lifetime supply of drug cocktails for long term HIV patients (which is all of them). Even a 10% reduction in the number of infections would free up a massive amount of resources at the NHS, CDC, and other agencies best suited to put them to use dealing with the remaining infections. Like with cancer and drug resistance, there is no single panacea but that doesn't mean we can't make big leaps that help a lot of people. Fighting a virus like HIV takes a lot of victories, big and small, that chip away at the problem until, like with smallpox or polio, there are so few cases left that each can be dealt with individually by the public health infrastructure.
- Jaruzel 10y ago
  > a significant amount of resources go towards a lifetime supply of drug cocktails for long term HIV patients (which is all of them) With my tin foil hat on, I've always wondered that now there is a very profitable business (for the big Pharma companies) out of just providing HIV positive people with drugs for years, that there is little appetite (again, inside big pharma) to actually 'cure' the disease...?
  - jack9 10y ago
    This doesn't make much sense, when very rich people (like Steve Jobs) get diseases and die. If there was a cure, at some point one of these ultra rich individuals would receive "the hidden cure" or have an overt relationship with a medical center leading to recovery. Being able to cure a disease, is generally more profitable for a generation (or more) as it's THE goto product and people are irresponsible enough that there's always new communication vectors.
ufo 10y ago
> Not my area of expertise but even if we can address 99% of strains, wouldn't that last 1% just take over and become the new 100% leaving us back where we started? Yes, this is something to worry about and is exactly the reason why it is so hard to find a cure for AIDS. HIV mutates inside the body into thousands of different configurations and no matter what treatment you throw at it there will generally be at least a couple of strains that will survive and take over. > Or is the promise here that we can combine this discovery with another that solves that remaining 1%? That would be hard. There is always a chance that the additional treatment will only treat 99% of that 1% and even a single surviving virus might be enough to restart an infection with resistant strains. > Or, do the mutations of that last 1% make HIV less virulent or harder to transmit? One of the other comments here, from someone that read the paper, says that the antibody found in this study binds very specifically to a part of HIV that is crucial for infection so the 1% of strains that resist the antibody (due to mutations in the binding site) are less virulent. The antibody also binds only to parts of HIV that mutate very slowly so it might mean that it would take longer for virulent resistant strains to evolve.

perlgeek 10y ago

> Not my area of expertise but even if we can address 99% of strains, wouldn't that last 1% just take over and become the new 100% leaving us back where we started? Not my area of expertise either, but as I understand it, it really depends on how many strains you are infected with. If it's just one, it'd reduce the infections in the next generation of patients by 99%. If the average patient had 10 strains, randomly distributed, it'd still reduce the infection rate by 90% (because there's a 10% chance of having that one resistant strain). Only if all HIV patience had all strains (and I'm pretty sure that's not the case) would it bring us back to where we started.

dogma1138 10y ago
You don't reduce the infection rate by 99% or by 90%, it's not even the correct term really. The transmission rate of HIV is not really dependant on the strain but on the behaviour of the affected host. Since HIV infection can be asymptomatic even for the natural life of a host the transmission rate is then dependant on the environment the social interaction of that host. A host that has unprotected sex (or any other risky activity as far as blood transmitted diseases go) and does not get tested regularly will have a considerably higher transmission rate than a host that has only protected sex and gets tested when they switch partners. Most HIV patients are infected with multiple strains, because at this point most new infections are multi-strain ones due to the lifestyle of the hosts and due to the fact that the virus can mutate in vitro. I'm also not clear how does this press release counts "strains", since it's 16 it's more than just by major types HIV-1 and HIV-2, but then it's the question of what and how they count sub groups. Most people in the west will get infected by HIV-1 Group M type B, type B itself can have several variations, and there are also host specific mutations, and if you are coinfected with another subtype you can have multiple variations of both and also recombinant (a new form made out of several types of the virus due to coinfection of a single cell) variations that may or may not be unique to each host. That said effective post infection and pre AIDS outbreak treatments can drastically reduce of new hosts that end up as transmission vectors and carriers, if HIV becomes a considerably more manageable disease that would allow most infected people to carry on with a normal lifestyle (safely have sex with a partner, and have children) once treated more people are more likely to be tested regularly. If you can also contain the disease to specific subtypes which are regionally locked as sad as it sounds you still doing quite a bit of good since now you can focus your resources on education and containment as well as further research since the transmission rates between say interveinal drug users in Berlin are considerably higher than between a sex worker in nairobi and the same drug users.

kendallpark 10y ago

It's all a statistics game. If you can vaccinate against 99% of current strains, you can severely stunt the spread of the virus with its current strain distribution. Combine this with adequate awareness about general prevention methods (safe sex practices) and you have a shot at severely reducing the incidence of the virus so that its numbers are small enough to control. New HIV infections are actually on the decline worldwide thanks to community awareness and ART meds that decrease the chances of spread. We've been able to eradicate or nearly eradicate several viruses from the planet. It starts with getting them down to manageable numbers, then addressing every outbreak. (Granted, HIV is not quite an analagous in terms of spread to viruses like smallpox.) https://en.wikipedia.org/wiki/Eradication_of_infectious_diseases#Eradicated https://en.wikipedia.org/wiki/Eradication_of_infectious_dise...

branchless 10y ago
If spread is reducing is it viable to simply manage this out over the long term? Or is that unrealistic.
- kendallpark 10y ago
  The difficulty is that once you're a carrier, you're always a carrier. With modern ART these people can be expected to live long lives. ART decreases the odds of transmission, but not everyone is compliant with their medications. Reducing the spread is one piece of the puzzle. The only way we've managed to "cure" HIV is through a bone marrow transplantation from a donor that have a mutant CCR5 receptor (which the HIV virus needs infect T-cells). I think that reducing the spread alone still could get us to a point where we "manage this out over the long term" as you say. Say you're a person with many sexual partners that has say a 1 out of 100 chance of sleeping with someone infected with HIV on a given day. Say there's a 1 in 10 chance that encounter will lead to transmission of the virus. (These aren't like factual numbers, just examples). That's still a 1 in 1,000 chance per encounter, so it adds up over time. After 1000 encounters chances are you've contracted HIV. But say you're vaccinated against 99% of the serotypes. That reduces your chance per encounter to 1 in 100,000. Even after 1000 encounters your chance of contracting HIV is 1 in 100. Not terrible.

orblivion 10y ago

It would seem to me that this concept of the strongest strain taking over only would happen if there were some sort of competition for resources. If you have one strain of HIV it seems weird to think that it would stop you from getting another strain and then passing both on. But "not my area of expertise" either.

nonbel 10y ago
First, it seems very difficult (for a virus) to transmit HIV via vaginal intercourse[1]. Second, most infections appear to start from a single virus,[2] despite the huge genetic diversity of intrapatient HIV that supposedly makes it hard to treat[3]. That means most of the strains found within one person never get transmitted. How do you manage to transmit HIV contaminated fluids but only one infection occurs in the receiving person? Very strange. Another strange thing, it does not seem all that difficult (relatively) for interspecies transmission to occur: "Scientists have now documented that the SIV virus has jumped from monkeys or apes into humans at least 13 separate times!"[4] Perhaps those transmissions are due to self-injury while cutting infected meat, etc. The vagina is tissue that expects the presence of foreign human cells, and so has defenses against them. Anal sex, injections, etc are a different story. To me it sounds like an entire cell gets transmitted. [1] http://m.jid.oxfordjournals.org/content/191/9/1403.full http://m.jid.oxfordjournals.org/content/191/9/1403.full [2] http://www.ncbi.nlm.nih.gov/m/pubmed/18490657/ http://www.ncbi.nlm.nih.gov/m/pubmed/18490657/ [3] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2614444/ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2614444/ [4] http://evolution.berkeley.edu/evolibrary/news/081101_hivorigins http://evolution.berkeley.edu/evolibrary/news/081101_hivorig... EDIT: Another possibility is that the vast majority of these variants found floating free in the blood are non-functional and serve as chaff to confuse the immune system.
Fomite 10y ago
The concept is known as "vaccine escape" and is present in some viral diseases but not others. I confess I don't know how between-strain viral dynamics of HIV work, but it was definitely a concern for HPV, though it does not appear to be happening.
ufo 10y ago

akiselev 10y ago

That unaffected 1% will still be limited by the rate of transmission which has been falling globally for decades because of growing access to birth control and antivirals, anonymous needle exchanges, and education. HIV isn't like a bacteria that grows out of control because the probability of transmission is highly dependent on the viral load, which varies significantly over the different strains and patients' lifetimes as their immune systems battle the virus. Even if eliminating 99% of strains only cures 50% of patients, those cured would have to have sexual or blood contact with the remaining 50% in order to get reinfected with the resistant strains. HIV is a very expensive disease to treat and since it's no longer a death sentence, a significant amount of resources go towards a lifetime supply of drug cocktails for long term HIV patients (which is all of them). Even a 10% reduction in the number of infections would free up a massive amount of resources at the NHS, CDC, and other agencies best suited to put them to use dealing with the remaining infections. Like with cancer and drug resistance, there is no single panacea but that doesn't mean we can't make big leaps that help a lot of people. Fighting a virus like HIV takes a lot of victories, big and small, that chip away at the problem until, like with smallpox or polio, there are so few cases left that each can be dealt with individually by the public health infrastructure.

Jaruzel 10y ago
> a significant amount of resources go towards a lifetime supply of drug cocktails for long term HIV patients (which is all of them) With my tin foil hat on, I've always wondered that now there is a very profitable business (for the big Pharma companies) out of just providing HIV positive people with drugs for years, that there is little appetite (again, inside big pharma) to actually 'cure' the disease...?
- jack9 10y ago
  This doesn't make much sense, when very rich people (like Steve Jobs) get diseases and die. If there was a cure, at some point one of these ultra rich individuals would receive "the hidden cure" or have an overt relationship with a medical center leading to recovery. Being able to cure a disease, is generally more profitable for a generation (or more) as it's THE goto product and people are irresponsible enough that there's always new communication vectors.

ufo 10y ago

> Not my area of expertise but even if we can address 99% of strains, wouldn't that last 1% just take over and become the new 100% leaving us back where we started? Yes, this is something to worry about and is exactly the reason why it is so hard to find a cure for AIDS. HIV mutates inside the body into thousands of different configurations and no matter what treatment you throw at it there will generally be at least a couple of strains that will survive and take over. > Or is the promise here that we can combine this discovery with another that solves that remaining 1%? That would be hard. There is always a chance that the additional treatment will only treat 99% of that 1% and even a single surviving virus might be enough to restart an infection with resistant strains. > Or, do the mutations of that last 1% make HIV less virulent or harder to transmit? One of the other comments here, from someone that read the paper, says that the antibody found in this study binds very specifically to a part of HIV that is crucial for infection so the 1% of strains that resist the antibody (due to mutations in the binding site) are less virulent. The antibody also binds only to parts of HIV that mutate very slowly so it might mean that it would take longer for virulent resistant strains to evolve.