Pregnancy – Risks for Men and Women

posted: 24/05/2010

Men have twice the risk of catching HIV when their partner is pregnant, say researchers. A study of more than 3,000 couples in Africa also backed earlier research that showed women are more at risk of HIV infection when they are pregnant. And pregnant women can transmit HIV to their baby, although this can now be almost always prevented. The researchers speculate that changes in a pregnant woman's immune system may increase the chance that her partner gets HIV.
 

Microbicides hope too
The findings were presented at the International Microbicides Conference in Pittsburgh, USA, alongside a separate study showing a microbicidal gel is safe to use during pregnancy to prevent HIV transmission.
 

Pregnancy HIV risks – to men as well
Several studies have shown evidence that pregnancy puts women more at risk of catching HIV from their partner, but this is the first time researchers have shown that men are more at risk of HIV susceptible to infection if their partners are pregnant.
 

The study, carried out in Botswana, Kenya, Rwanda, South Africa, Tanzania, Uganda and Zambia, involved 3,321 couples in which one partner was HIV-infected and the other not.
 

Over two years there were 823 pregnancies, and analysis showed that pregnancy increased both male-to-female and female-to-male infection. For the women, it seemed that factors other than pregnancy contributed to the increased risk of HIV infection.
 

But for the men, the link between pregnancy and their risk of infection was much clearer, even after accounting for other factors, such as having unprotected sex. The woman’s viral load and CD4 couple made no difference to whether HIV was passed on to the man.
 

Study leader Dr Nelly Mugo, from the University of Nairobi and the University of Washington in Seattle, said it could be that biological changes during pregnancy make a woman more infectious: "increased female-to-male transmission of HIV during pregnancy may be due to physiological and immunological changes that occur with pregnancy." It may also be affected by the couples sexual behaviour.
For more information on the Pittsburg conference M2010, go to: http://www.microbicides2010.org
 

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German Risk Statement

posted: 27/04/2009

We have had the Swiss Statement, now their neighbours, the Germans, have issued their own on the risks of HIV transmission from people taking HIV treatment successfully.

The Swiss told us last year that people on HIV treatment, if they meet certain conditions, can be considered uninfectious. Now the largest HIV voluntary sector organisation in Germany, Deutsche AIDS-Hilfe, has issued a paper largely supporting this statement.
 

The German paper describes sexual transmission, where the HIV-positive partner is

• adhering to effective combination therapy,
• has had an undetectable viral load for the last six months and
• has no sexually transmitted infections,

as ‘unlikely’ and describe this as being as effective as using condoms. They add that it is also important that there is no other damage to either person’s mucous membranes.

Stable, long-term different-HIV-status relationships
Both the German and Swiss organisations say their statements are relevant to stable, long-term relationships where one partner has HIV. After the couple has made a decision, based on good information and advice, regular viral load testing and sexual health check-ups are recommended.
 

HIV is sometimes found in semen even though it is undetectable in blood.

However, Deutsche AIDS-Hilfe argues that relying on effective treatment as a means of HIV transmission prevention is a realistic HIV prevention approach, and that individual couples already  make decisions about the level of risk they take.

Read the English language version of the German statement

Swiss statement report

Oral Sex, Tiny HIV Risk

posted: 17/12/2008

For about 20 years we have said oral sex is low-risk, not no-risk for HIV transmission. Now researchers have tried to say how low the risk really is. This is not so easy to check as you might think.

The risk of HIV transmission during oral sex is very low, but not zero, conclude researchers from Imperial College and the London School of Hygiene and Tropical Medicine. They tried to find all the studies, but found that the lack of data meant they still can't make a broad estimate for the transmission risk through oral sex.

They started with a systematic review (an analysis of all the medical research that meets their standards). The studies reviewed include data from heterosexual, lesbian and gay couples, covering both fellatio (oral sex on a man) and cunnilingus (oral sex on a woman).

Only 10 studies count

Only ten studies were judged to be good enough to include in the review. All were from Europe or North America, and only three used data from after HIV combination treatments became widespread.

Problems

The researchers point out the many problems with measuring oral sex risks for HIV.

• Very few people only have oral sex.
• If a person has both unprotected oral sex and unprotected anal or vaginal sex, and acquires HIV, their HIV infection is automatically attributed to the more risky anal or vaginal route, not to oral sex.
• Data on individuals’ self-reported sexual behaviour is hard to collect accurately, especially because people tend to give more socially acceptable answers (i.e. pretending to have been "good" and not "admitting" sex without condoms).
• Studies frequently group all oral sex practices together, without separating out the oral sex acts by who was doing what to whom, which person has HIV, if there is ejaculation in the mouth or not, and if so, the spit or swallow choices.
• Studies of serodiscordant couples (where one person is HIV-positive and the other is not) are likely to include people with well-controlled viral load, meaning that they are much less infectious than during primary infection (the first few weeks after HIV infection when people are the most infectious they will ever be). Oral sex transmission is more likely during primary infection. Oral sex transmission of HIV is also more likely when one or both have certain other sexually transmitted infections (STIs), especially those STIs that have sores. 
• Studies which do identify a risk from oral sex are more likely to be published and reported than those which do not, because of the interest and comparative novelty of such a finding.

Estimates of the per-partner transmission risk - zero to 20%!
Five of the studies provided estimates of the risk of multiple oral sex acts during the life of a sero-discordant relationship.Three of these studies gave that estimate as zero – no transmissions were reported.

The fourth study provided a figure of 1% for receptive fellatio.

The fifth study, from Sweden, provided a much higher estimate of 20%. However the sample was very small (ten couples reporting oral sex as their only risk factor), and the review authors comment that the high estimate may be due to under-reporting of higher risk activity, or simply due to chance. Moreover, this is the only reviewed study which identified any HIV transmission among heterosexuals that could be attributed to oral sex.

Estimates of the per-partner incidence, per 100 person years
Three of the studies also reported estimates which calculated the transmission risk of multiple oral sex acts, but with the duration of the relationship stated. In each case, the estimate was zero.

Estimates of the per-study-participant transmission risk
Three further studies followed HIV-negative people who reported unprotected oral sex as their sole risk factor. However the authors note that these studies have additional methodological limitations: the number of sexual partners and their HIV status is not known. This implies that the findings cannot be transferred to other populations where numbers of partners and HIV prevalence are different.

Two American studies gave estimates of 0% and 0.4% respectively, and the more recent Canadian Omega cohort provided a figure of 0.5%. Each study was conducted with gay and bisexual men.

Estimates of the per-act transmission risk
Three studies attempted to calculate the risk of HIV transmission during a single act of oral sex.

Two studies both provided zero estimates – no transmissions were reported.

The third study is Vittinghoff’s often cited paper which used data from American gay or bisexual men who reported multiple risk behaviours. Mathematical models were employed to estimate the risk of different sexual acts, and unprotected receptive oral sex with ejaculation was calculated to have a 0.04% risk of HIV transmission. However the review authors note that this estimate is based on sex with both infected and uninfected men – if the researchers had been able to exclude sex with HIV negative partners, the figure would have been higher.

Conclusions
The authors note the paucity of data to inform this review. Reliable estimates would be important for prevention workers and clinicians advising people on the relative risks. Moreover, because of the low risk of transmission, "large and expensive studies" would be required to provide more precise estimates.

They also comment: "The fact that infected study participants with solely this exposure have remained difficult to identify may suggest that indeed the contribution of orogenital intercourse to HIV incidence remains low."

Nonetheless they do recommend that "individuals should protect themselves using condoms or dental dams to minimise this small risk."

George House Trust comment - STIs and gum disease raise risks

After 20 years we are no nearer answering the oral rex risk question with scientific accuracy. The balance of the evidence is clear - the risk is minimal.

But from other research we know that the risk of HIV (and STI) transmission during oral sex is far higher when people have other STIs (herpes, syphilis, gonorrhoea included) either in their mouth or genitals. It is also higher when people have gum disease and other mouth and throat infections. Both STIs and gum disease increase the risk of transmission during oral sex because they can provide an open pathway into the bloodstream for the HIV virus.

We can reasonably expect that oral sex risks are highest in these situations, especially when people are in the much more infectious primary stage of infection (within the first two months of themselves becoming infected). For people at other times, and especially for those people on treatment with undetectable viral loads, the transmission risk would seem to be very close to zero.

In terms of prevention priorities, fretting about the tiny oral sex risks is a diversion from the things that would really make a difference to the annual numbers becoming infected, including consistent condom use in anal and vaginal sex, reducing the numbers of people with undiagnosed HIV as far as possible, and actions which prevent transmissions during the most infectious first few weeks.

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