Dar es Salaam. The quest for truth among scientists about the controversial injectable, Depo-Provera, seems to be persistent three years after the World Health Organisation allayed public fears about the possible link of the popular contraceptive with the risk of HIV transmission.
Depo-Provera, a contraceptive widely used by women in Sub-Saharan Africa was again last week associated with increasing the risk of HIV spread among users this time round, by 40 percent, according to a study published by US researchers on Friday in The Lancet Journal.
In what appears like scratching old wounds, the latest findings might trigger another global debate on the injectable—like the one which was closed by the WHO in 2012—the year when similar claims about the injectable were dismissed by the world health watchdog.
In the 2011 October Edition of theLancet Infectious Diseases Journal, researchers from the University of Washington had revealed that women living in Aids-hit countries who used Depo-Provera were twice as likely to become HIV positive as other sexually active women.
The study was particularly worrisome for African communities, where hormone injections are the most popular form of contraception and where roughly 25 million people are living with HIV--accounting for nearly 70 percent of the global threat, according to current WHO reports.
More than 3,700 women in Tanzania, Kenya, Botswana, Rwanda, South Africa as well as Uganda and Zambia were enrolled for the study that put public health officials in a bind.
The argument from scientists who published the findings was that the injectable caused changes in a woman’s birth canal--and increased the couples’ vulnerability to HIV infection during intercourse.
In other words, it also meant that the users who live in HIV endemic areas were at higher risk of being infected because, by using the injectable it means that they did not care about practicing protected sex with partners who would probably infect them with HIV.
The findings proved a major dilemma to public health authorities and threatened to disrupt family planning efforts among the many poor countries where the injectables are already wide-spread.
Many women in Sub-Saharan Africa prefer this type of family planning because it’s convenient for them, lasts for months—and women don’t have to take and keep track of it--like in other daily birth-control pills that they also use in trying to avoid the risks of carrying unintended pregnancies.
In Tanzania, injectables are the most preferred methods of contraception by couples--used by 11 percent of married women, according to Tanzania’s current Demographic and Health Survey (TDHS, 2010).
According to global statistics, about 144 million women use hormonal contraception and around 41 million uses the injectable forms while 103 million take the oral contraceptive pill.
Whether or not the use of hormonal contraceptives increases women’s risk of getting HIV has been hotly debated for more than two decades now, but studies done on the matter have been inconclusive so far.
With the latest revelations by scientists from the University of California at Berkeley-- where 12 observational studies from Sub-Saharan Africa involving 39, 560 women have been analyzed, much is till desired in terms of getting to the truth, according to the scientists.
There are grains of undisputed truth that the World Health Organization did not quench the thirst of many public health researchers—especially when the debate was apparently closed three years ago.
But this time around, it also means that the debate on Depo-Provera might still go unabated--simply because the WHO’s directive in 2012 about the controversial injectable was itself not conclusive.
In 2012, a group of experts from the WHO had intervened to examine the evidence after the ‘’Depo-Provera--HIV link’’ sparked off a huge international consternation, especially from among family planning experts who criticized the study.
Most of those who opposed the findings based their criticism on the fact that only few women were using the injectable in developing countries and that the sample would not be a good representative for the targeted population—meaning that more research was necessary before any conclusions were made.
Despite all weaknesses observed in the study, when theWHO group of experts convened to sort out the controversy, they faced a difficult time in dealing with the evidence against the Depo-Provera—a drugmanufactured by a US pharmaceutical company, Pfizer.
To end the international furore, the panel, which comprised 75 WHO experts from 18 countries, did not put forward a straight conclusion.
They said that the evidence published at that time was not strong enough to prove or disaprove an increased risk of HIV transmission by Depo-Provera—a move that appeared to have settled the matter.
However, the panel reiterated that condoms were still the most reliable method for preventing both HIV and pregnancy, and advised couples in which one partner is HIV infected, to always use a condom--regardless of the type of contraception—injectable or pill-- they had agreed to use as a couple.
But now, what does all this debate mean to the users of the injectable and,who is telling the truth—the WHO or the researchers? Some people even asked last week,when The Citizen on Sunday published a story on this subject, that: ‘’if there is evidence that Depo Provera is not safe, why not withdraw it to stop HIV transmission?’’
The latter question was answered on Friday by the lead author of the study, Lauren Ralph, an epidemiologist at the University of California at Berkeley who cautioned that the evidence in the latest study did not warrant withdrawal of Depo-Provera from supply.
She explained; “The moderate elevation in the risk observed in our study is not enough to justify a complete withdrawal of DMPA [Depo Provera] for women in the general population,” arguing that “Banning [the injectable] would leave many women without immediate access to alternative, effective contraceptive options.’’
But the first question—who is telling the truth?—could be better answered by looking at the type of studies that have been done on Depo-Provera, whereby most of them are observational studies but not therandomizedcontrolled trials.
In medical research, observational studies aren’t taken as seriously as controlled or blinded trials. ‘’The notion is that observational studies don’t fully reflect the truth.’’
Every study that has linked Depo-Provera to HIV infection has been observational and this is part of the problem with trying to get at “the truth”---when scientists can’t find the real biological mechanism that will explain how Depo-Provera makes women more vulnerable to HIV infection.
Even when certain bigger reviews were done on it, they were quashed. In 2013, a review of the observational data estimated that the same injectable was associated with 48 to 100 percent increase in HIV transmission risk.
That would mean an additional 27,000 to 130,000 cases of HIV globally each year--88 percent of which would occur in Sub-Saharan Africa.