Frank information on HIV transmission

November 8, 2009 in Uncategorized

Warning:  the following passages are very graphic but I think they are important because they are a very frank, nitty-gritty discussion on HIV transmission with helpful hints on how you can protect yourselves and others. They are written by Elizabeth Pisani, Phd.  Elizabeth is a epidemiologist who has been involved in HIV study and prevention programs since 1994.  Formerly, she was a journalist so she knows how to write.  An epidemiologist who can write clearly is a very rare bird. 

 

Here is a link to her blog: http://www.wisdomofwhores.com/

 

Here is what the reviewers  say:

 

Joanna Busza in the British Medical Journal “Pisani is renowned for having developed among the best behavioural surveillance methods around, and she describes putting them into practice with poignancy and humour”

 

The New England Journal Of Medicine says    “  …required reading for anyone who works on HIV and AIDS or in the broad field of global public health…”      and      “…Pisani reminds her readers that the real work of fighting the epidemic is done in these highly specific trenches of sex and drug use. It is a take-home message that is worth remembering.

 

I offer these excerpts from her 2008 book The Wisdom of Whores: bureaucrats, brothels and the business of AIDS.  The book is an amazing analysis of the politics, sociology and public policy aspects of HIV prevention and treatment with very interesting people stories and much wry humor.

 

 

 

 

“So let’s run quickly through what we know about HIV.

 

We know that HIV hangs out in blood and genital fluids but not saliva.  Saliva confuses people because you can do an HIV test on saliva.  That’s because most commercial tests look for antibodies to HIV, which survive in saliva, rather than the virus itself, which doesn’t.

 

We also know that HIV is not actually all that infectious.  Unlike other viruses such as hepatitis, HIV can’t survive for long outside the body, and can’t survive at all outside of body fluids.  Of course, if you take infected blood and pump it straight into someone else’s body, you’ll be almost guaranteed to generate a new infection.  That’s why it is so important to screen blood for HIV before a transfusion.  Injections, too, can put the virus right where it needs to be.  If someone comes at you with a syringe in a clinic or hospital where HIV prevalence is high, make sure the equipment is new or has been properly sterilized.  If you’re injecting heroin, steroids or even insulin, use your own needle.  If you don’t you risk giving HIV an express ticket into your bloodstream.

 

Sexually, though, the virus has a much harder time.  It can’t pass through the body’s own line of defense – the mucus-covered surfaces that line most of the entry points to our bodies.  To take up residence in someone else’s body, HIV more or less needs to be invited in through an open door.  And injections aside, there are not all that many things that can open a door.  The main ones are small tears and lesions around our genitals (or in our anus, in the case of anal sex), and the presence of cells which are especially welcoming to HIV.

 

Forgive me for getting graphic, but as you probably know, sex can be a sticky business.  The stickier the better.  The more mucus there is, the less danger there is that the friction of sex will tear your inner fabric.  A wet vagina is usually a pretty safe environment.  This is one reason why foreplay is a good thing – stimulation and anticipation make a woman wet, and therefore safe.  It is also a reason why HIV is so easily transmitted in forced or unwanted sex……(here the author talks about how sex when dry causes tears which provide open doorways for the virus)

 

The anal passage does not get wet in anticipation of sex.  On top of that, its lining is not very thick.  It is not a great idea to have anal sex without using an artificial lubricant.  For one thing, it hurts.  But more importantly (from HIV’s point of view), it is quite likely that you’ll get scratched up inside, so if one of you is infected, you can pass HIV on quite easily to the other.  Don’t assume this is only relevant to gay men.  A landmark study of heterosexual couples by Isabelle de Vincenzi …found that women who reported anal sex were over five times more likely to pick up HIV from their infected partner than women who only had more conventional vaginal sex.

 

The other things that poke holes in the body’s natural barriers are other sexually transmitted infections, especially the ones such as syphilis and herpes which cause ulcers.  These wounds, external in men, internal in women, provide easy passage for the virus, out of one body and/or into another.  They have other drawbacks, too, The particular genius of HIV is that it attacks the very cells that are supposed to fight off disease.  If you have another sexual infection the body’s defense forces (white blood cells known as T cells) come in to attack it.  Now your genitals are swarming with T cells, and T cells are especially susceptible to HIV infection.  Another express ticket for HIV.

 

Another warm welcome is provided by the Langerhans’ cells which sit on the inside of the foreskin that covers the uncircumcised penis.  Because circumcision lops off these cells, it closes one of the doors through which HIV might enter a man’s body.  It also toughens up the end of the penis, so that lesions are less common.  You can still get infected if your circumcised, especially if you’re having anal sex or other forms of sex that are particularly abrasive.  But HIV spreads much more slowly in countries or cultures where most men are circumcised.

 

Another thing I get asked about a lot after a glass or two of wine is oral sex.  It is a risk for HIV or not?  Because there’s no HIV in saliva, it’s pretty hard to pass HIV on to someone else by going down on them unless you’ve got bleeding gums.  HIV prevention programs don’t like to tell you this, but really, if you go to the dentist regularly the likelihood of infection in oral sex is vanishingly small.

 

Without special treatment, about one in three of the women who have HIV while they are pregnant will pass HIV on to her infant either in the womb, when the child is born, or during breastfeeding.  One of the things which determines whether the child will be infected or not is how much virus there is in the mother’s blood.  The amount of virus in your body fluids (what the doctors call the ‘viral load’), is critical is sexual transmission, too.  Viral load varies depending on how long you’ve been infected with HIV.  When the virus first walks through an open door into a new body, it steals a march on the body’s defenses and multiplies like mad.  Then the immune system swings into action, creating antibodies that attack the virus.  Although the immune system is never able to kick HIV out entirely, because the virus sneaks off to hide inside healthy cells, it does bring it under some kind of control.  The viral load goes way down, and usually chugs along at very low levels for several years, although other infections can cause it to spike.  Sexually transmitted infections are especially good at pricking up the levels of HIV in semen and vaginal fluids, which makes onward transmission much more likely.  This is another reason why it is a good idea to treat curable STI’s.

 

………So, HIV is transmitted when the viral load is high.  Your viral load is high immediately after you get infected – a time when you may well be doing risky things.  After all, you got infected for a reason.  It is high again when your are sick and close to death, when you’re probably not going to have much luck picking up new partners, even if you have the energy to try.

 

That means most people who pass HIV on sexually do so when they’re newly infected – often within the first six months.  In fact, a lot of HIV is probably transmitted before a person could even test positive for the virus.  Obviously, that’s nearly impossible to measure.  But one case was brought to light courtesy of the health and safety regulations in the US porn industry.  Porn stars are tested for HIV regularly.  One stud who tested negative on 17 March 2004 had unprotected on-camera sex with thirteen women in less than a month.  Then he tested positive, and the health authorities went back and tested all his partners.  We usually bandy about rather low transmission probabilities in heterosexual  contact – as low as 1 in 300 for male-to-female sex.  But three of the women became infected by this one man – an attack rate closer to 1 in 4.  They had some fairly unusual sex – I’ll leave you to guess what ‘double anal’ sex is – but it was still a far higher rate of transmission than one would normally expect.  And it was almost certainly because our screen stud had a brand new infection, and his semen was seething with HIV.

 

The virus will spread most quickly in situations where people have several sex partners on the go at any one time, because they will be able to pass the virus on to all of them in their highly infectious first few months.  If on top of that you have lots of untreated STIs, which spike the viral load and open doors for genitals fluids, you’ll accelerate the pace.  Genital herpes is particularly good at fanning the flames of HIV: over two-thirds of adults have herpes infection in many badly affected areas.  Transmission will go faster still if a lot of men are not circumcised.”

 

End quotes.  To me the take away lessons are:  treat other STIs as quickly as possible, if you have herpes avoid sex when experiencing an outbreak, avoid anal sex but if you don’t then use plenty of lubricant, make all your sexual activity as juicy as possible (foreplay is fun).  If you are uncircumcised, make sure that your penis tissue does not have any irritations or tears.  If you have bleeding gums, treat them quickly and avoid oral sex until they are healed.  And last but not least, become as healthy as possible through diet, exercise, rest, etc.  And, though Elizabeth does not mention condoms in these excerpts, condoms are effective to prevent transmission.