Bloodborne HIV: Don't Get Stuck!

The New York Times reviews Dr Jacques Pepin’s ‘The Origins of Aids’, which aims to shed light on how rapidly expanding twentieth century public health campaigns may have been responsible for the spread of HIV and other blood-borne diseases in French and Belgian colonies from the 1920s onwards. Patients on such programs could get up to 300 injections in a lifetime. As a precedent, a schistosomiasis (bilharzia) campaign in Egypt that ended in 1980 infected more than half the recipients with hepatitis C, which is still more widespread in Egypt than in any other country in the world.

The book, ‘The Origins of AIDS’, is by Dr Jacques Pepin, whose papers on the subject have been discussed on my HIV in Kenya blog in the past. Starting 60 years before the disease was even noticed, the book aims to tie up some of the many mysteries about how a disease that is now said to be almost always transmitted sexually could have spread to become a pandemic, infecting over 20 million people in a handful of sub-Saharan African and another 15 million people throughout the rest of the world. 25 million are estimated to have died from AIDS.

The author himself admits that he may have inadvertently infected some of his patients because the process of ensuring that injecting equipment was sterile was often lacking. He was working on a schistosomiasis epidemic in the early 1980s, before HIV had been recognized. But it was when Pepin went on to work with HIV-2, HIV-1 being the more widespread and more deadly of the two, that the question of how a virus that was difficult to transmit sexually could become a (partly) sexually transmitted pandemic.

People with HIV-2 can live for a long time and it was only found in older people at the time he started working with it in Guinea-Bissau. This suggested that it was dying out, as it was not spreading among young, sexually active people. So Pepin sought an alternative mode of transmission that allowed HIV-2 to have once flourished, and then die out. He began to investigate various public health campaigns against syphilis, yaws, leprosy, TB and others, which went on until the 1960s. Notice, some of the groups targeted by such campaigns would have overlapped with those currently targeted by HIV campaigns, being sexually transmitted.

Pepin looked for evidence that blood-borne diseases other than HIV had been spread by injections, circumcisions and other skin breaking practices. He also noted the colonial public health programs’ keen interest in sex workers and various other practices that may relate to sexual behavior. But when the virus jumped from chimps to hunters, the whole process consisted of such low probability events that sexual transmission alone would never have allowed HIV to become a pandemic; it would have just died out, having only infected a handful of people.

This is where Pepin’s notion of an ‘amplifier’ comes in. He found that blood transmission of HIV is 10 times more efficient than sexual transmission. But the amplifier in colonial African countries was the public health campaigns, with their heavy use of injections. It was only later, once public health campaigns had spread the virus throughout many populations, that sexual behavior became responsible for further transmission.

Interestingly, Pepin says that sexually transmitted infection (STI) eradication campaigns ceased some time before the contribution of sexual transmission to the HIV epidemic increased. But in the Nairobi instance cited, where HIV prevalence went from 5% to 82% in three years, it seems possible that an STI eradication campaign may have played a part in spreading HIV among sex workers, rather than sexual behavior alone explaining the massive prevalence rate recorded in the mid 1980s. After all, HIV prevalence among sex workers, along with other STI rates, declined sharply after about 1986, and the downward trend continued well into the 1990s.

Again, when HIV spread to Haiti, Pepin notes that the virus was unlikely to have been spread very widely through sex alone. This time, he suggests as an amplifier a plasma donation center, which operated in the early 1970s. The process involves donating blood from which the plasma is extracted and the remainder is injected back into the donor. If unsterile equipment was reused this would risk spreading HIV and other blood-borne diseases. This route of HIV transmission has been well demonstrated in other countries and may still occur.

These blood products were exported to the US. Haiti was also well known as a sex-tourism destination, especially for gay sex, so this would have played a part. Anal sex, whether male to male or male to female, is a far more efficient transmitter of HIV than penile-vaginal sex. And thus, the earliest discovered victims of HIV and AIDS were men who had sex with men and hemophiliacs. The former are still at higher risk than those who don’t engage in anal sex; the latter are still at risk in countries where the safety of healthcare can not be guaranteed, such as all the medium and high prevalence countries in Africa.

Let us hope that the work that Pepin has started will prompt an investigation into the possibility that unsafe healthcare may still be responsible for HIV transmission in some resource-poor areas. Efforts to influence people’s sexual behavior, which go back many decades, starting with efforts to reduce STI rates and birth rates and continuing right up to the present, have had few successes, if any. But investigating the many cases of HIV infection where sexual contact is unlikely to have been responsible, or unlikely to have occurred, could present a far more effective, and less stigmatizing way of reducing HIV transmission.

[I have used this NY Times review to relate Dr Pepin’s research to other research into the relative contribution of non-sexually transmitted HIV to the current pandemic. Since writing the above, I have had the opportunity to read The Origins of Aids and have made some comments on the HIV in Kenya blog (hivinkenya.blogspot.com); more should follow once I’ve had time to read some of his sources.]