HIV Transmission – All the Facts

posted: 14/04/2010

Clear, full, accurate information about HIV transmission can be hard to find. Even recent ‘official’ sources may mislead. For example, one NW England council’s HIV guide for schools suggests HIV transmission could happen at school.

While almost anything could happen at any school, HIV transmission is exceptionally unlikely, without risky sex - and that is not part of the curriculum. Suggesting HIV transmission could happen at school is unhelpful and tends to increase anxiety and feed HIV stigma.
 

HIV transmission without sex, without injecting drug use, or without mother to baby transmission is exceptionally rare. Of over 34,000 HIV diagnoses in the UK from the beginning of the epidemic to 1997, only 19 happened in non-sexual 'unusual circumstances' . Most of these ‘unusual’ transmissions were at clinics abroad, where infection control procedures were slack.

Everything you ever wanted to know about HIV transmission but were afraid to ask

Visit the HIV transmission section of the NAM / aidsmap website for detailed information on subjects including co-factors that affect transmission, viral load and risk of transmission, and protective measures.

NAM also produce a comprehensive book, HIV Transmission & Testing, available from their online bookshop.
 

Hepatitis C - Blood Blamed

posted: 13/11/2009

Contact with blood, not semen, is how hepatitis C is being passed on among some gay men living with with HIV. This is what is now being reported at the European HIV conference underway in Cologne, Germany.

Fisting, group sex, and snorting drugs emerged early on as significant risk factors for sexual transmission of hepatitis C. But unprotected anal sex on its own, without fisting, parties and snorting drugs, doesn't seem to transmit hepatitis C. 

The investigators believe we should refocusing hepatitis C prevention campaigns for HIV-infected gay men from warning about unprotected sex to warning about transmission, probably through tiny, usually invisible, droplets of blood.

Since 2000 outbreaks of sexually transmitted hepatitis C have been reported amongst HIV-positive gay men in a number of large northern European cities including London, Amsterdam and Berlin. Unprotected anal sex and fisting were quickly identified as risk factors.

Semen or Blood?

But is hepatitis C transmitted through the semen (like HIV), or through blood in these encounters?

Because men living with HIV have a higher hepatitis C viral load in semen than men without HIV, this could explain the higher rates of hepatitis C among HIV positive gay men. But HIV-negative partners (of gay men with both HIV and hepatitis C) almost never get heptaitis C, so it looks like it isn't transmitted through semen. HIV-positive heterosexual couples where one partner also have hepatitis C don't infect each other either. This points strongly to blood, not semen, as the means of hepatits C transmission among HIV+ gay men.

Positive gay men in Bonn

Investigators in Bonn did a case-controlled study involving 34 gay men with both HIV and hepatitis C, and 67 age-matched men who only had HIV. None of the men reported injecting drug use.

The men were recruited to the study between 2006 and 2008. They provided information on their sexual and drug use behaviour, and also stated if they had experienced rectal bleeding as a consequence of sex.

Unprotected anal sex was widely reported, and approximately 50% of men reported receptive fisting.

So how does the blood get transmitted?

The first set of statistical analysis showed that several risk factors were associated with infection with hepatitis C including

• use of sex toys
• rectal bleeding
• receptive fisting without gloves
• sharing and snorting stimulant drugs like cocaine and amphetamine during group sex.

Only these three things were clearly linked to heptatits C transmission when they did a more detailed multivariate analysis:

• receptive fisting 
• rectal bleeding 
• drug use during group sex.

So the researchers propose hepatitis C is being transmitted via blood rather than semen, and that even men without hepatatis C can be involved in a transmission chain, during group sex sessions.

Some disagreement

However, not all delegates at the conference were convinced. A questioner from the floor pointed out that many HIV-positive people with acute hepatitis C infection in London do not report fisting.

Moreover, Dr Sanjay Bhagani told aidsmap that it was his sense that the epidemiology of hepatitis C amongst HIV-positive gay men in London was changing and that many infections could probably be attributed to injecting drug use rather than sex.

In addition, HCV itself is sometimes found in semen, and men who have both HIV and HCV tend to have HCV in their semen more often than men who have HCV but not HIV, according to a report from Canadian AIDS Treatment Information Exchange.

Nevertheless, the investigators conclude that prevention messages should inform HIV-positive gay men of the risks of hepatitis C that arise from long-lasting, group-sex sessions where there is rectal trauma caused by activities such as fisting. The blood may not be visible - microscopic amounts are enough - hepatitis C is vastly easier to pass on than HIV.

Source with more details and reference