Expert: Terry B - 11/21/2006

Question
Thank you for the help. I found that in the US its 8.6 death per 100,000. I've taken the US population divided it by 100,000 and then multiplied that number by 8.6 for approximately 25,666 deaths per year.  I also found statistics stating that there are approximately 40,000 newly exposed HIV cases per year. Doing the math that is approximately 109 per day or approximate. 1 exposure per 13.3 minutes per day in the US. I think my math and formula is correct in terms of breaking these large numbers into something dramatic that will catch peoples attention. Does the process I am using sound logical to you?  I am a theologian not a math person.

Thanks,

Chaplain Justo Gonzalez, II, M.Div., M.S.S.A., M.A.P.M.
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The text above is a follow-up to ...

-----Question-----
I am writing an article on World AIDS Day. I'd like to quote the probability of HIV/AIDS exposure both globally and in the US. I'd like to say you have a 1 in 4 chance or whatever the number turns out to be.  Can you help me with this?  

Justo Gonzalez, II
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Justo -

Thanks for your efforts to raise awareness.  What you ask for is actually part of a science called Epidemiology; a short answer will have to suffice for now and I encourage you to look deeper for meaningful answers to your question.

An easy way is to take the number of people known or estimated to be infected and place that number over the population.   For round numbers, let us say Lower Petunia has a population of 100 million people, and 25 million of them are thought to be living with HIV.  We would say that the HIV prevalence is 2500 for every 100,000 people.    This would mean that chances of being exposed are 1 in 4 overall (25/100 = 1/4).

Now - one reason epidemiology is a science is that there are many factors in choosing what population is "at risk" = this would most likely include persons recently born (mother to child transmission), persons most sexually active (usually identified as somewhere between 12 and 45 or so), and/or working in professions where exposure to blood, blood products, semen, vaginal secretions, or breast milk might occur.  These people would be seen to be at higher risk than others; by narrowing in on that population, you should find that they are at a risk higher than the 1 in 4 from our example.  

Anyway, that's the way you take prevalence (how many living with infection) and turn it into "chances" of being exposed.  As you can hopefully see, it is a little more complicated when trying to apply the percentages to your audience.

In the US, the Morbidity and Mortality Weekly Report (MMWR) provides data on HIV prevalence in the US and for specific populations.  Internationally, World Health Organization and UNAIDS are two sources for data.  

Welcome to the world of Public Health!

Good luck!

Terry

Answer
Dear Chaplain Gonzalez:

Peace and good tidings this Thanksgiving season!  

Let me share a lesson hard-learned from training most health professionals; when one starts talking about rates, one loses the audience (unless one is addressing epidemiologists or public health professionals).  Once, as part of a four hour training, I gave a fifteen minute presentation on global, national, and local HIV rates.  Commentary from evaluations said it was "too long" - I adjusted my presentation from that point forward, to greater success.  I maybe able to help you bring the salient points home.

I do not know if you are a hospital or military chaplain, but in either case, depending on your audience, try to anticipate their risk.  Specifically, if hospital audience include not only information about HIV in general population, but also history of infections from provider to patient and vice-versa.  If military, focus in on the breakdown of diagnosed HIV and AIDS cases by age group.  As noted in earlier email, the number of new infections in both groups will be higher than those in the general population.

I would enjoy discussion of AIDS/HIV and Theology at some point, as I am currently engaged in Interdisciplinary  doctoral studies concerning religion and medicine.  I am also a former Navy corpsman and director of a clinic; I may have additional resources or suggestions appropriate to your setting.  Send a "private" response through this forum including your email address and I may have some additional information of use to you.

Sincerely,

Terry