The complication of prevention as treatment

I’ve been thinking about the Economist articles celebrating 30 years in the fight against HIV/AIDS since it came out in early June. The discussion of the success in research trials (HPTN052 to be exact) showing that providing anti-retroviral medications (ARVs) to HIV+ individuals who are in relationships with HIV- individuals (together making a discordant couple) gives us all hope.  Hope has been in short supply as of late, as it becomes clear that the development community and the population at large is reaching fatigue about HIV/AIDS and the global economic crisis is putting pressure on financial assistance for the developing world in general.  But, in this particular case, I find that the hope is short-lived.  While we now have scientific evidence that this intervention works (because the common sense evidence has been there for some time), I fear it is not enough. More importantly, I believe that the assertion that through “hard pounding (we are) gradually bringing AIDS under control” is an over enthusiastic misstatement that may have serious repercussions.

My colleague Grant Miller, an economist who teaches at Stanford, taught me a simple lesson about how to measure whether if something works.  He explained the difference between efficacy and effectiveness.  It’s simple, but often not put into practice.

Efficacy is the measure of how well something works when it is done as intended.  This means, full and perfect compliance and fully adopted.  Effectiveness is the measure of how well something works in the presence of incomplete adoption or unintended behavioral responses.  Generally this is the different between how we plan something and what really happens.  And we all know, if we are really honest, that almost nothing ever happens the way we plan it.  Granted, this sometimes leads to amazing insights, genius moments and surprisingly wonderful results.  And sometimes…disaster.

The more difficult an activity or the more frequently it needs to be completed leads to reality resembling our plans less and less.  A program through which ARVs are provided in the developing world is full of issues that makes the likelihood that reality will differ from the intention.  For example:

– One must take the drugs twice a day, every day for the rest of one’s life at approximately the same time and most people in the developing world don’t wear (or own) a watch.

– Due to the cost and to promote regular check-ups, individuals are generally given enough medication for only one-month, after which they must return to the clinic, which may be hours away and require taking a day out of working and cost a significant amount for transport.

– The supply of ARVs is unreliable, frequently due to issues in funding, poor inventory planning at all levels, and broken transportation systems.

– ARVs can either make the patient feel great or feel terrible, in both cases they might stop taking the medications.

All of these issues, and more, contribute to how outside of a controlled research study we may see a much less optimistic picture of the effectiveness of providing ARVs as a means of treatment acting as prevention.  For with this approach, as many others including the ABC methods (Abstinence, Be faithful and use a Condom), a consistent lifetime change in behavior is needed.  Even for those interventions, which require more change from the system than from individuals (e.g. male circumcision, working with high risk populations, supporting family planning activities, and providing ARVs to pregnant women) implementing the change is difficult.

Behavior change is difficult for everyone.  Think about the last time you tried to improve your diet, add to your exercise regimen, or get to sleep on time.  Have you ever broken a New Year’s Resolution?  Even those activities that we know are good for us, they are hard.  And so, we shouldn’t underestimate how challenging these changes can be for someone who is struggling to make ends meet, keep their family together, just get out of bed, and keep the reason for their struggle a secret.

I maintain hope that there is a way to prevent the spread of HIV and I believe strongly that those who are ill should receive treatment as a matter of course.  But, I want the agencies and governments that are implementing these interventions to be careful that they consider the unintended consequences and unexpected situations that will inevitable crop up.  And, that those who support these efforts to realize that in order to continue the impact we are seeing in this issue, that sustained and increased funding is necessary.


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