How did researchers fail to find what’s driving Africa’s HIV epidemics?
October 11, 2011
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How to find what’s driving Africa’s HIV epidemics
HIV is not an easy virus to catch – it needs memorable skin-piercing events or intimate sexual contact. So it shouldn’t be too hard to find out why so many Africans are getting HIV. How? Find people with new infections, ask them about recent sex partners and skin-piercing events (injections, tattoos, accidents), and then go look for the source.
- Trace and test sex partners to see if any are HIV-positive.
- See if people with new infections got injections or other skin-piercing procedures from clinics that did sterile instruments; test others who visited the same clinic to see if they, too, were infected.
Then check to see if HIV someone with a new infection is a close match to HIV from a sex partner (if they are infected) or from one or more people who attended the same clinic (if they were infected). If you find a match, then you have very likely found the source.
Researchers didn’t trace the source of new infections
Over the past 30 years, international and foreign organizations have funded a lot of research on HIV in Africa. This research includes 44 randomized controlled trials during 18987-2011 that tested interventions to prevent HIV in adults (see appendix table in this link). In these trials, researchers recruited adults, then divided them into two or more groups: one group got nothing (no intervention) while another group or groups got something that — it was hoped — would protect them (for example, antibiotics to syphilis, circumcision). Studies then followed all adults to see who got new HIV infections.
How did these studies fail to explain what is different about HIV in Africa? As crazy at it seems – they didn’t ask, didn’t look, and didn’t report what they found. Collectively, these studies identified >4,000 new infections: >900 in men and > 3,100 in women. But studies didn’t look for the sources of these infections. (The details of this failure are described in a review available here or from the Social Science Research Network.)
Not looking for a sexual source
- Only 4 of 44 studies traced HIV-positive sexual partners — spouses only long-term partners only — and checked to see if HIV from both partners were similar, which was good evidence that one infected the other by sex. These 4 studies traced a total of only 186 infections (<5% infections in 44 studies) to long-term sexual partners (see table 5 in this link).
- No study traced and tested any spouse or other long-term partner that was not already enrolled in the study.
- No study traced and tested any non-spousal partner.
Not looking for a blood-borne source
- No study identified any facility that provided skin-piercing procedure to anyone with a new HIV infection.
- No study investigated sterilization practices in any facility that provided injections or other skin-piercing procedures, or tested any other patient or client attending such facilities.
Even so, other evidence from these studies suggests blood-borne and sex risks are equally responsible for Africa’s epidemics
Aside from tracing infections to their source, a less decisive method to identify risks responsible for new infections is to see people with new infections vs. people without new infections were more likely to report risks. Here’s what the 44 studies report:
- Only 5 of 44 studies reported recent sexual risks (having any vs. no sex partner, or less than 100% condom use) for people with or without new infections. According to the median (middle) results from these 5 studies, having any unprotected sex was responsible for less than 30% of new infections (see table 6 in this link).
- Only 5 of 44 studies reported skin-piercing procedures in people with new HIV infections (5 reported injections, two reported transfusions, two reported hospital or clinic visits without specifics about skin-piercing procedures). Looking for the median (middle) result from these 5 studies, reported skin-piercing procedures and hospital or clinic visits appeared to be responsible for roughly a quarter of all new HIV infections (see table 7 in this link).