Modeling HIV in China

In October my master’s student had her work on modeling HIV interventions in China published in the journal AIDS, with me as second author. You can read the abstract at the journal website, but sadly the article is pay-walled so its full joys are not available to the casual reader. This article is a sophisticated and complex mathematical model of HIV, which incorporates three disease stages, testing and treatment separately. It is based on a model published by Long et al in the Annals of Internal Medicine in 2010, but builds on this model by including the effects of methadone maintenance treatment, and doesn’t include an injecting drug use quality of life weight. It also adds new risk groups to the model: Long et al considered only men who have sex with men (MSM), injecting drug users (IDU) and the general population, but we added commercial sex workers (CSW) and their clients, who we refer to as “high risk men.” Thus our mathematical model can consider the role of both injecting drug users and sex workers as bridging populations between high-risk groups and the general population, an important consideration in China.

The HIV epidemic in China is currently a concentrated epidemic, primarily among IDUs in five provinces, and amongst MSM. The danger of concentrated epidemics is that they give the disease a foothold in a country, and a poor or delayed response may cause the epidemic to jump to the rest of the population – there is some suggestion this may have happened in Russia, for example. The Chinese authorities, recognizing this risk, began expanding methadone maintenance treatment (MMT) in the early 2000s, but it still only covers 5% of the estimated 2,500,000 IDUs in China. Our goal in this paper was to compare the effectiveness of three key interventions to prevent the spread of this disease: expanded voluntary counseling and testing (VCT); expanded antiretroviral treatment (ART); and expanded harm reduction (MMT and needle/syringe programs); and combinations of these interventions. VCT was assumed to reduce risk behavior and expand the pool of individuals who can enter treatment per year; ART was assumed to reduce infectiousness; and harm reduction to reduce risk behavior. Costs were assigned to all of the programs based on available Chinese data, and different scenarios considered (such as testing everyone once a year, or high-risk groups more frequently than everyone else).
The results showed that all the interventions considered are cost-effective relative to doing nothing; that some of the interventions saved more money than they cost; and that the most cost-effective intervention was expanding access to ART. Harm reduction was very close to ART in cost-effectiveness, and would probably be more cost-effective if we incorporated its non-HIV-related effects (reduced mortality and crime). The Chinese government stands to reap a long-term benefit from implementing some of these programs now, through the 3.4 million HIV cases averted if the interventions are successful (there are a lot of “ifs” in that sentence).This is the first paper I’m aware of that compares ART and harm reduction head on for cost-effectiveness, though subsequently some Australians showed in the same journal that needle/syringe programs (NSP) in Australia are highly cost-effective as an anti-HIV intervention. This is also the most comprehensive model of HIV in China to date, and the first to conduct cost-effectiveness analysis in that setting. I think it might be the first paper to consider the detailed structure of risk groups in a concentrated epidemic, as well. There are obvious limitations to the conclusions that one can draw from a mathematical model, and some additional limitations on this model that are specific to China: the data on costs was a bit weak (especially for MMT) and of course there are questions about how feasible some of the interventions would be. We also didn’t consider restricting the interventions to the key affected provinces, which would have made them much cheaper, and we didn’t consider ART or VCT interventions targeted only at the high-risk groups, which would also have been cheaper. For example, legalizing sex work and setting strict licensing laws might enable universal, quarterly HIV testing and lead to the eradication of HIV from this group within 10 years, but we didn’t include this scenario in the model because a) legalization is not going to happen, b) enforcement of licensing laws is highly unlikely to be effective in the current context in China, and c) data on the size and behavior of the CSW population is probably the weakest part of our model, so findings would be unreliable. Despite the general and specific limitations of this kind of modeling in this setting, I think the results are a strong starting point for informing China’s HIV policy. China seems to have a very practical approach towards this kind of issue, so I expect that we’ll see these kinds of policies implemented in the near future. My next goal is to explore the mathematical dynamics of these kinds of models with the aim of answering some of the controversial questions about whether behavioral change is a necessary or effective part of a modern HIV response, and the exact conditions under which we can hope to eliminate or eradicate HIV. Things are looking very hopeful for the future of HIV, i.e. it’s going to be eliminated or contained in most countries within our lifetime even without development of a vaccine, and that’s excellent, but there is still debate about how fast that will happen and the most cost-effective ways of getting there: hopefully the dynamic properties of these models can give some insight into that debate. This article is a big professional achievement for me in another way. It’s extremely rare for master’s students to publish in a journal as prestigious as AIDS (impact factor over 6!), and my student’s achievement is a reflection of her amazing talent at both mathematics and English, and a year of intense work on her part, but I like to think it also is a reflection of my abilities as a supervisor. There were lots of points where we could have let things slide on the assumption that master’s students don’t publish in AIDS; but we didn’t, and she did. I like to think the final product reflects well on both of us, so read it if you get the chance!

 

Modeling HIV in Japan

I’m in Nagasaki this week to attend the 86th Annual Meeting of the Japanese Society for Infectious Diseases, where I have presented the results of my work building a mathematical model of the HIV Epidemic in Japan. The model is currently submitted to a journal so I can’t give any detail about it here, but I can present a chart I used in the conference presentation, that is based on publicly available data from the Ministry of Health, Labour and Welfare. This chart shows the number of new cases of HIV/AIDS notified to the government annually, divided into three main transmission modes (Figure 1).

Figure 1: Annual new cases of HIV/AIDS in Japan by transmission category, 1985-2010

In this Figure, “same sex contact” means “homosexual contact,” since there’s no such thing as a case of HIV transmitted by same sex contact between women. From Figure 1 it should be pretty clear that while the epidemic appears to have peaked and even beginning to decline in the heterosexual population, amongst men who have sex with men (MSM) it is growing rapidly. Now, there are some caveats on such a conclusion in Japan: testing rates are quite low so it could be that these “new” cases are actually old cases that have only just been identified, for example, but it would be a strange world indeed if the entire slope of that line were due to remnant cases finally coming to light. So, it’s reasonable to conclude with some confidence that the HIV epidemic is growing rapidly amongst MSM in Japan. Currently prevalence is probably low, but that was the case in Australia back in 1985, and prevalence amongst MSM in Australia now is probably above 5%.

This comparison is noteworthy because Figure 1 makes it look like Japan’s experience of HIV is Australia’s 20 years ago, and if the epidemic continues to follow Australia’s trend, HIV will spread rapidly through Japan’s gay community. Of course there are big differences in HIV treatment and prevention now compared to 20 years ago, and very few people die of AIDS in Japan because of the combination of low prevalence and good treatment. But the rapid increase amongst MSM shown in Figure 1 suggests that prevention efforts to date haven’t been working, and it would be best if something could be done to prevent the further spread of the disease.

Another minor concern (raised in my presentation, actually) is that MSM in Japan tend to be less open than in the rest of the developed world, making them even harder to study but also raising the possibility that they marry and have at least some sexual contact with women. Sexuality in Asia is, in general, more fluid than in the West and less constrained by categories and boundaries, so the idea seems superficially plausible. If this is true though, it means that there is a small risk that the epidemic won’t be contained within the gay community forever. Unfortunately, no one knows the extent of this overlap in Japan, and no one knows how much injecting drug use is happening here, so it’s hard to make judgments about how such behavior might affect the future of the epidemic. This is what my mathematical modeling is (partially) aiming to do, and although I won’t reveal the results here the future is not pretty for MSM if the epidemic is allowed to continue. Even without the benefit of a mathematical model, it’s pretty easy to see from Figure 1 that Japan needs to improve interventions amongst MSM, primarily by increasing rates of voluntary testing and targeting a test-and-treat prevention strategy at this community. Given the current low prevalence of HIV, even a relatively unsuccessful test-and-treat program will probably be sufficient to contain the epidemic (though the international evidence suggests that it takes a very rigorous and probably unrealistically well implemented program to eliminate the disease). It remains to be seen whether such a targeted approach will be tried here, but hopefully my work will be one tiny step towards encouraging such a change.

 

The Grim Reaper Turns 25!

Not someone you want to go bowling with...

Twenty-five years ago today the Grim Reaper appeared on Australian television to warn us about the dangers of HIV. You can see the ad through this article about the anniversary. I was 14 at the time, and it was truly terrifying. I think it did its job, and scared Australians into sexual responsibility, though now that we have treatments and testing and the like, people may be beginning to become complacent again. Although it now seems a bit hammy, I think it also compares favourably with British health and safety adverts – it’s not as tacky, and makes its point much more succinctly and believably. I particularly like the nod to the holocaust when the narrator says it could kill more people than world war 2 – a nice touch, very understated but very effective.

There was some controversy at the time, because some people interpreted it as likening gay men to the Grim Reaper (at that time it was largely a disease of gay men), but unlike in the USA there was a much better relationship between government, health workers and gay activists, and the controversy didn’t damage the ad’s effectiveness. Of course now people think that the kinds of things being said in this advert were hyperbolic or alarmist, because Australia has largely escaped the problem of HIV – another complaint made at the time was that this ad was overdoing it, and would contribute to that general suspicion people have that government health messages are just intended to scare us. But take one look at the situation in Africa and it’s clear that Australia dodged a very, very scary epidemic, and with our large drug-using population it was possible that HIV could have crossed to the heterosexual population by the early 1990s. It didn’t, and we can thank Australia’s early and very impressive response for our very lucky escape. Part of that response was this cute guy with his scythe and his slightly tatty cape, and we Australians should all be thankful for whatever small part he played in keeping us safe. So, thanks and … happy birthday Grim Reaper! If you get laid at your party, remember that prevention is the only cure we’ve got!

 

Imperialism and Circumcision

Many Australian public hospitals maintain a ban on circumcision. The Royal Australian College of Phsyicians (RACP) recommends against circumcision, and it is now so unpopular that 80% of Australian boys are uncircumcised. However, a committee of public health experts has recommended reversing this ban and moving to encourage circumcision, on the basis of the many health benefits of circumcision. These health benefits have been known for a long time, but the medical fraternity have responded to strong public pressure in advising against non-medical circumcision, because it is seen as a form of child abuse. Indeed, in America recently there were efforts to ban the practice on the basis that it is a form of child abuse.

This would all be a largely irrelevant debate about men’s willies and the aesthetics thereof, except that circumcision has now been shown to be an extremely effective tool in the battle against HIV. The Bill and Melinda Gates Foundation and various international aid agencies are scrambling to fund circumcision programs in Africa, where they believe that this simple and harmless procedure can significantly reduce the transmission of one of the world’s nastiest diseases. Recently at a training course in the UK I met people involved in this process and saw examples of the kinds of non-surgical devices being used to circumcise adult men (it’s a kind of ring, and after just 1 or 2 days the whole process is over and you can go back to work).

Australia is undoubtedly contributing financially and organizationally to this effort as part of its increasing aid contributions to Africa. But isn’t there something wrong here? Circumcision is essentially banned in government run hospitals in Australia, is on the nose in the USA and is frowned upon in the UK, yet these same countries are recommending circumcising the entire African continent. It’s morally unacceptable child abuse in Australia but an acceptable public health intervention in Africa? How does this kind of attitude differ from previous eras when population control was conducted through sterilization, often not clearly explained to the recipients? Is it just another example of aid-as-imperialism? How is this different to a country where abortion is strictly illegal (say, Ireland) funding abortion-based population control programs in Africa? And how can the Australian aid community (or its public health activists) criticize Chinese aid programs while we’re doing something like this?

It’s also worth remembering that historically white colonialists have been extremely uncomfortable about black men’s sexual fecundity (and their mythically enormous willies). Yet here we are – advocating chopping the end off of those massive, fecund members in the interests of stopping a disease which (apparently) cannot be stopped in Africa through behavioral change alone. Even though in Australia we have it under control through – you guessed it – behavioral change. The public health double standard is disturbingly close to the sexual insecurity …

Don’t mistake me here – HIV is a desperate situation and circumcision a minor operation that I don’t think we should shy away from as a control technique. Furthermore, I think the western bans on circumcision are silly and of the same character as the AMA’s opposition to boxing. It’s not liberal. But this hypocrisy, in which doctors won’t tolerate it in Australia or the UK but will support funding for its widespread use in Africa, reeks to me of cultural imperialism. If you won’t tolerate it here, don’t do it there.

 

NHS Beset by Magical Thinking (again)

Simon Jenkins, Guardian columnist, ex-HIV Denialist and public health skeptic has a column up at the Guardian that contains his recommendation for dealing with the NHS. Unsurprisingly, his basic recommendation (like every other article he writes on public health risk) is – let them eat cake. Essentially worthless, in a roundabout way it aims at a solution and provides a couple of examples of the kind of magical thinking that lots of free market “solutions” to the NHS’s problems are prone to – and shows why they discredit the real, simple market solutions that might make the NHS work better.

But before we get onto the substance of the article, let’s just contemplate what Jenkins’ presence on the pages of the Guardian has to say about journalism as a profession. This is a man who for several years in the early 1990s was so staggeringly wrong about the science of health that he sided with the HIV denialist movement, writing articles that opposed the link between HIV and AIDS long after the dust settled. The consequences of HIV denialism in Africa are pretty well understood now, and very sad, but here we have this man still writing on health-related topics – and specifically, on disease prevention – in the pages of a major UK newspaper. This is like giving editorials on NASA to a moon-landing skeptic. But somehow journalism manages to struggle on in this way, giving a dangerous idiot high profile space to spread idiocy and lies. And the lies haven’t even changed – his work on swine flue alarmism used pretty much the same arguments as his HIV Denialism. Oh journalism, what happened to you?

So now Jenkins has moved on to health policy, ever an important topic in the UK, in the wash-up of a report from the NHS Ombudsman on appalling mistreatment of old and/or very sick people in some hospitals. The report itself is summarized here and here. Jenkins provides us with a long list of the reorganizations that have been tried in the NHS over the past 50 years, and concludes that the NHS is “too big” and is best broken up – sacking 24,000 back office staff is a good start, apparently. We find Jenkins wondering why no-one has bothered to try and properly reorganize the system, and instead done all this tinkering at the edges, and suggests that the NHS is so big and powerful that it won’t allow internal change. And he also suggests that instituting top-down targets will encourage staff not to care about their patients. I want to look at these ideas in a little more detail, because they illustrate some of the common problem ideas that strident armchair observers force into the debate – ideas that are unproductive or even harmful to the interests of health policy in the UK.

The NHS Is Too Large To Change

Jenkins’ first point is that the NHS is too large to change, that it can successfully resist external tinkering because it is its own monster. He points to the long history of attempts at reorganizing the NHS and asks why they all fail. He says that

Its interests are too institutionalised, its lobbyists, especially the doctors, too powerful, and its internal controls so pervasive as to seize up the system.

but he doesn’t consider a far simpler explanation. The NHS is the main source of healthcare for 64 million people, and there is currently not a great deal of health care capacity outside of it. Has it occurred to Jenkins that the reason attempts to reorganize the NHS fail is that they need to occur slowly and cautiously? It’s very easy to propose radical solutions from the outside, as a senior journalist who can guarantee himself access to what little private health capacity exists in the UK. But for someone like David Cameron or Andrew Lansley actually attempting to modify the system, there are the interests of another 63,999,999 people to consider. You can’t afford to just break that shit overnight with a radical change – you need to be absolutely certain that the system won’t tip over. Yes, let’s break it all up – and if rather than breaking it up, we just break it, who suffers? Certainly not the top opinion writers at the Guardian.

The reason that the NHS has so much institutional weight is that, even though it isn’t the best system in the world, it works, and it works for 64 million people, most of whom have grown up with no alternative system, and couldn’t afford it if it were there. As a politician, it’s not just your own career on the line if you fuck that up – it’s a lot of people’s health. You tread carefully with a system that has that much weight.

The NHS Is Too Large

The next complaint Jenkins makes is that the NHS is just too large. It should be less mammoth. But if it is so large, why is it underfunded relative to the rest of Europe? As a nationalized health system, there is every possibility that it is not large enough, and needs further injections of funds before it can be said to be large enough to do its job effectively. It may be the case that the NHS as a single institution is too large to be effective, but it may just as well be the case that it is not large enough to serve the needs of its population. The more diversified health systems of Europe may be doing better, but they’re also getting a lot more money and have been getting a lot more money for a long time. We don’t have any evidence that the NHS would be performing worse than those systems if it had received the same historical funding.

Targets Discourage Caring

This is arrant nonsense. Health care organizations have always had top-down targets, regardless of the system they work in. Here’s an example of a target: we want 0 post-operative mortality this year. Here’s another: We want 0 prescribing errors this year.

Do those targets discourage ordinary staff from caring for their patients? No, quite the opposite. The impact of a target depends on the system it is instituted in, its suitability for the staff it effects, and the amount of funding and system support for the achievement of that target. It also depends on staff supporting it, and on the existence of infrastructure and management systems that help that target be achieved. The oldest Doctor’s target – first do no harm – is pretty useless, for example, if you have to treat HIV with ineffective medicines because some thick journalist convinced the government that HIV doesn’t cause AIDS.

For some reason a lot of British journalists and health critics have a problem with targets that way exceeds their meaning. Sure, targets can be useless – they can even make it harder for staff to get their job done – but this critique doesn’t necessitate the level of demonization and magical thinking that attends the dreaded T word in some journalistic and (largely, though not exclusively, Conservative) policy circles in the UK. Caring, wholesome nurses don’t suddenly become dark eyed witches because the government set a target on the number of teen pregnancies in their health area that year. Such a suggestion is magical thinking at its finest.

Sacking “Back-office staff” will get the System Working

This is another common refrain of the “common sense” brigade, the old-school unionists and (again, largely, though not exclusively, Conservative) policy radicals throughout the world. Its of a piece with the misperception of publicly-funded health systems as inefficient “public service” that employs people for make-work jobs. And, it’s largely impossible to conceive of as a sensible policy recommendation if one has ever actually worked in a hospital environment. Once one has, it is pretty obvious that these “back office” staff – supposedly so useless compared to their brave and peerless contemporaries, so-called “frontline staff” – are much harder to define and much more necessary than the policy radicals recommend. Exactly which back end staff should we be sacking here – the ones who process the salaries? The ones who enter the data that we use to track hospital quality? The ones who clean the floors? The ones who process the purchase orders that get the syringes to the bedside?

I worked as “Back office staff” for 3.5 years in a community health centre in Sydney. During this time:

• I implemented a new methadone maintenance dosing database that reduced the risk of dosing errors (that can kill)
• I merged this system with a client management system that enabled a coherent system for managing dangerous and troublesome clients, reducing (potentially very dangerous) confrontations
• I implemented a new system of direct data entry that enabled us to reduce the amount of staff time spent on data entry – freeing staff up for frontline service!
• I helped to coordinate the development of a statewide data standard for collecting information on hepatitis C treatment and management
• I implemented a client management system for the newly-opened Medically Supervised Injecting Centre, which enabled us to both research the efficiency and effectiveness of the service, and manage client movement and injecting in what could best be described as a challenging work environment
• I provided data analysis for ministers, health service planners, and my organizations staff – for training days, tracking new problems, and monitoring our performance

So, who was going to do this if I didn’t? And how in the long-term is the health system going to continue to operate at its best if these functions are retarded and slowly disappear from the organizations that form the whole? Do the policy radicals and idiot journalists who vent this type of inane policy “fix” consider that every private organization beyond a certain size has a similar set of “useless” back office staff, who keep the frontline people working smoothly? No, because they see the word “National” in “NHS” and a red film descends over their eyes. It’s a publicly funded service, so anyone who is not directly and immediately doing something that can be described as “health” must be wasting the public dollar.

This is ideology, not sense. But you’ll read it all the time in critique of publicly funded services everywhere.

The Private Market and the Grain of Truth

Of course, Jenkins has managed, by driving his buick very haphazardly, to swat the fly. The NHS could be improved – it could be made more responsive to patients, to health problems, to new threats and new technologies – by

denationalising, regionalising, introducing market forces, contracts, choice, anything to reduce bulk

and he correctly notes that this has been the plan for 20 years. Ultimately the way to improve the NHS is to “break it up” in some sense – to move towards the more decentralized mixed systems of Europe and Australia and Japan, where private and public providers compete for public money to treat patients who largely pay for the service they receive through taxes. Every movement in the NHS over the last 20 years has been towards this system, if not in essence then in practical fact. But no matter how much policy radicals and idiot journalists rant about it being too big, the fact remains that the health system in the UK is underfunded – in private and public contributions – and has been for a long time, and until it catches up with the European standard, too-rapid decentralization would be a disaster. Furthermore, with the British private sector very underdeveloped relative to other nations, time and investment is required. This can’t happen overnight because to dump 64 million people onto the tender mercies of a system that has been moribund and underfunded for 30 years, with no alternative, would be a policy disaster. So health policy in the UK moves slowly and consistently towards this goal, as successive governments find ways to loosen up the NHS and prepare the groundwork for a more flexible, more modern system, while people on the far left and the far right of the debate[1] watch the whole thing, and miss the point.

But the absolute worst thing that could happen while that movement occurs is for the people in charge of it to start thinking that the cause of the NHS’s problems is its overall size, and start hacking into it with gleeful abandon. Which is why people like Jenkins really need to stop talking about health and talk about something better suited to their moral and intellectual stature. I propose football.

—

fn1: And with health care, in the UK at least, it seems like you don’t have to stray very far to the left or the right to start behaving like you are “far” from the centre. The state of commentary on healthcare in the UK is really rather woeful.

 

 

 

Zombies, Public Health and HIV

Reading World War Z has got me thinking about a lot of different things, but the first thing I noticed was the way in which the modern Zombie tale has increasingly become a commentary on (and, generally, an endorsement of) modern public health and disease prevention principles. Of course, public health principles applied in the breach can ultimately lead to a huge dose of fascism, by which I’m not referring to the anti-smoking campaigns of the modern era, but the extremely draconian and almost-never used quarantine and control rules that governments reserve for the most severe disease outbreaks. And we see these being enacted in every zombie tale – or, if they’re not used, the society in question coming to regret it. In fact, the zombie tale can easily be read as a peon to the public health route not taken – on HIV, on SARs, etc.

In an interesting literary parallel, World War Z reminded me of the excellent oral histories of the early years of the HIV epidemic, which show a similar tone to the early parts of the book, with doctors and community activists trying desperately to work out what is happening before a previously unknown disease wipes out a community. Only the transmission method was a little different, though zombification and HIV show similar issues of incubation period and origin. We even have real life examples of HIV consuming societies, and modern history would have been very different if HIV had progressed through the West the way it did in Africa. I can’t believe that the modern resurgence of zombie stories is unrelated to our own recent development of public health consciousness, and a lot of that development stemmed from the HIV epidemic.