Dear Dr G,

I am a novice when it comes to sex. I often hear about the risk of HIV transmissions and that is enough to send chills down my spine and put me off sex!

Perhaps I am being overly cautious, as I have not engaged in penetrative sex, even though I am well into my late 20s.

You can imagine I have missed out numerous opportunities in universities with girlfriends, and now even at work.

My friends all think I am weird, as I am constantly trying to work out the risk of sexually transmitted infections.

I guess being an accountant, you would think it is in my character to work out the calculations before engaging in any form of risky behaviour.

I am hoping to put Dr G on the spot today for the exact risk and possible protective measures against the contraction of HIV.

Firstly, can you please tell me the exact risk of HIV transmission?

What sort of sexual act would be the most risky?

And what are exact risks of transmission for oral, vaginal and anal sex?

Finally, can you tell me what measures I can take to prevent HIV transmission?

Yours truly,

Cautious Caleb

THE highest risks of transmission of the HIV virus are unprotected anal sex, unprotected vaginal intercourse, needle sharing and vertical transmission from mother to baby.

It is difficult to put an exact risk of HIV transmission to different modes of sexual behaviour, as the viral load of the infected person is not always known.

The likelihood of HIV transmission from a person with HIV to a HIV-negative individual depends on the mode of sexual activity.

The state of immunity of the HIV-negative partner is also difficult to quantify in scientific studies.

However, clinical data is available to help individuals to work out exactly how risky each encounter can be during sexual contact.

Fellatio and cunnilingus (better known as oral sex) are sexual acts that involves one person kissing and licking the other person’s genitals. All the scientific data agrees the risk of HIV infection from oral sex is low, but it is not risk-free.

In fact, a study actually quoted risks as high as 3%. HIV is not transmissible through saliva alone. The risk of transmission during oral sex depends on bodily fluid containing the virus (semen and vaginal secretions) entering the bloodstream of the HIV-negative person if there are inflammation, cuts or sores in the oral cavity.

The risk of contracting HIV through cunnilingus is near impossible, and there is no documented case of such transmission.

Globally, the most frequent route of transmission is unprotected vaginal intercourse. There are differences in biological risks of viral acquisition for men and women, also in high- and low-income nations.

A woman is twice as likely to contract HIV from a virus-positive male partner, and in low-income countries, transmission rates are higher and seem to be similar among both sexes.

The calculated risk of viral transmission to women having sex with HIV-positive men is 0.08% (which translates to 1 in 1,250) and risk to men from infected women is 0.04% (1 in 2,500).

In low-income nations, the risk is 1 in 300 for both sexes.

Unprotected anal intercourse carries the highest risk of HIV transmission. The virus is more likely to pass from a HIV-positive partner to the receptive partner.

In a recent study in Australia, the accurate calculation of per-act risk of receptive anal intercourse to both men and women was estimated to be 1.4%.

This translates to a 1 in 70 risk of contracting HIV.

The prevention of HIV can be as straightforward as ABCD.

A stands for Abstinence; without the sexual act, the risk of sexually transmitted infection is clearly negligible. However, if Abstinence also involves some degree of oral sex, then the risk would clearly increase accordingly.

B stands for the Barrier technique. Analysis found that couples using condoms all the time can prevent HIV transmission by up to 90%, even with one partner diagnosed positive.

C stands for Circumcision. Although technically this is not a preventive measure, the recent meta-analysis of observational studies in Sub-Saharan Africa reveals the protection against HIV can be as high as 60% in men after circumcision.

Finally, D stands for Drugs. The introduction of antiviral medications has turned out to be an absolute game-changer in the prevention of HIV.

A recent study that observed 888 couples, with one HIV partner with antiviral drugs inducing zero viral load, having unprotected intercourse for over three years.

The risk of HIV transmission was reduced to zero. This clearly is the scientific breakthrough many have hoped for!

When it comes to sexually transmitted infections, taking risks and going too far may mean visits to the doctor when faced with infections such as chlamydia or gonorrhea.

The risk of transmission when engaging in high-risk sexual activity is often the subject of discussion.

Many men (and occasionally women) ask me to outline the exact risk of transmission with each mode of sexual contact, sadly this is also with reference to the ultimate price to pay for serious infection such as HIV.

One of my favourite authors and the 20th century’s major poets, TS Eliot, once said: “Only those who will risk going too far can possibly find out how far one can go.”

When Dr G is put on the spot for his opinion of risk reduction to prevent HIV transmission, his view is: “Not risking going too far by taking the steps of ABCD, one can slowly explore how far one can go!”

Leave a Reply