Saturday, February 19, 2011

Are Most HIV Positive Infants Infected by Their Mother or by Unsafe Healthcare

HIV figures from a recent survey in Mozambique paint a fairly typical picture of prevalence patterns in underdeveloped, high prevalence African countries. People in the richest quintile are three times more likely to be infected than those in the poorest quintile.

Women with secondary or higher education are 50% more likely to be infected than women with only primary education or less. Men are a lot less likely to be infected than women. And less well educated, poorer men are less likely to be infected than well educated, wealthier men.

So, what kind of transmission scenario is responsible for these patterns? Well, it is clear that more than one scenario is needed. The one official scenario used to explain all high prevalence African epidemics at the moment is that of unsafe sex.

We are supposed to believe that huge numbers of Africans engage in unsafe sex most of the time, despite safe sex messages and education being pumped out by the hour for many years. Apparently, those urban dwellers with greater access to the media and to the benefits of education, public services and health care are at greater risk of being infected.

Which tends to suggest that the single scenario is just wrong. But the 'behavioral paradigm', the belief that almost all HIV transmission occurs via heterosexual sex, is still the official view of UNAIDS, the US Center for Disease Control and most major academic institutions working with HIV.

To take one example, are we supposed to believe that rich women with higher levels of education living in urban areas have a tendency to pay people who are at high risk of being HIV positive to have sex with them? This may happen, but is it such a common phenomenon that it drives one of the worst HIV epidemics in the world?

Who exactly is infecting these women? Are they paying rich men to have sex with them? And if their rich, male spouses are paying for extramarital sex with high risk, casual partners, who are these partners? If they are poor, uneducated, rural dwelling people, they are less likely to be infected, in which case they are also less likely to be spreading the virus.

In order to explain why those with greater wealth, education and access to public services and healthcare are more likely to be infected, one needs to posit some other mode of transmission than heterosexual sex. Men who have sex with men (MSM) are a recognised risk group, as are injecting drug users (IDU). But these groups tend to infect other MSM and IDUs a lot more than people who belong to neither of these groups.

More than a hint at what could be going on comes from the same report that the above findings are based on, the Demographic and Health Survey. An estimated 30% of HIV positive infants have HIV negative mothers (the document is in Portuguese). If their mothers did not infect them it is highly likely that they were infected nosocomially, that is, through some kind of unsafe medical procedure, such as an injection. Anyone, infant, child or adult, can be infected nosocomially.

And not only can infants be infected by their mothers during delivery or breastfeeding, but infants can also infect their mothers through breastfeeding. This can happen if a baby is infected nosocomially. Also, the number of infants infected nosocomially may be a lot higher than 30%. The fact that the mother is HIV positive does not necessarily mean that the infant was infected by their mother.

The number of pregnant women and women who have recently given birth who seroconvert late in their pregnancy, or some time in the months following delivery, is very suspicious. Most women take precautions while they are pregnant and when they have recently given birth to protect themselves and their infants.

Are we supposed to believe that many African women are not just highly promiscuous but also either stupid or careless about their health and the health of their infants?

A far more convincing scenario to explain all of the above phenomena is that people are not only infected with HIV through heterosexual sex. Many, perhaps even a majority, are infected through unsafe healthcare.

Women, especially those around childbearing age, face more invasive medical treatment than men. Richer people can afford more healthcare than poorer people, who often do without altogether. And those in urban areas have greater access to healthcare while those in rural areas often have no access whatsoever.

Some HIV transmission may occur through heterosexual sex, especially in a country where prevalence has reached such alarming levels. And those who are infected nosocomially can also transmit HIV sexually. But at present they are not considered to be 'high risk', nosocomial infection is not targeted by HIV prevention campaigns and people at risk don't even know about the risks they face from unsafe healthcare.

The single scenario, naive theory of HIV transmission through heterosexual sex raises more questions than it answers. But the dual scenario, non-sexual and sexual transmission theory answers all of the questions. None of these remarks are particularly new, nor do they apply to Mozambigue alone. So now all we have to do is convince UNAIDS, CDC and other big players in the HIV industry.


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