Transmission and Prevention

How is HIV transmitted?
The main ways of HIV transmission are:

Unprotected sexual intercourse with someone who is infected.
Injection or transfusion of contaminated blood or blood products, skin grafts and organ transplants taken from someone who is infected.
From a mother who is infected to her baby; this may be during the course of pregnancy, at birth and through breast-feeding.
Sharing unsterilised injection equipment that has been previously used by someone who is infected.

Is oral sex unsafe?
Oral sex (where the mouth of one person comes into contact with the genital organs of the other) carries a minor risk of HIV infection. The risk is lower than for other penetrative sexual acts as the virus gets killed in the digestive tract of a person. There is minimal risk if there are bleeding gums or tiny sores somewhere in the mouth and the virus from the semen or vaginal fluids enters these sores and consequently the blood stream. The use of condoms or latex barriers can further reduce the already low risk through oral sex.

Why is injecting drugs a risk for HIV?
When an HIV infected drug user injects himself with the drug using a needle or syringe, some of his blood enters the syringe. When the same syringe is used by another drug user, the infected blood can be injected directly into the second person’s bloodstream.

Infected blood can be introduced into drug solutions by using blood-contaminated syringes to prepare drugs, reusing water, bottle caps, spoons, cookers or other containers used to dissolve drugs in water and to heat drug solutions, reusing small pieces of cotton or cigarette filters used to filter out particles that could block the needle. Repackaging and sale of used syringes is not uncommon and could also be a risk for onward transmission of HIV.

Can I get HIV from getting a tattoo or through body piercing?
The risk exists if instruments contaminated with blood (including the inkpot) are either not sterilised or disinfected and reused on clients. All instruments that can penetrate the skin should be used once, then disposed of or thoroughly sterilised.

Are health care workers at risk of getting HIV on the job?
The risk is very low if they carefully follow universal precautions (ie, using protective practices and personal protective equipment). They are mainly at risk through accidental injuries from needles and other sharp instruments that may be contaminated with the virus. Scientists estimate that the risk of infection from a needle jab is less than 0.3 % in most cases where the needle prick is a surface scratch.

Are patients in a dentist's or doctor's office at risk of getting HIV?
Unsafe health care is responsible for much of HIV transmission, especially in poorer countries where medical care is routinely compromised. While patients are not likely to get HIV from health care providers who are HIV-positive, patient-to-patient transmission through unsterile instruments is a serious concern. All procedures which are invasive (pierce the skin) carry a risk of HIV transmission if instruments are unsterile. The careful practice of infection control procedures, including universal precautions, protects patients as well as health care providers from possible HIV infection in medical and dental offices.

Can I get infected with HIV from mosquitoes?
There is no evidence of HIV transmission through mosquitoes or any other insects. HIV lives for only a short time inside an insect and, unlike organisms that are transmitted via insect bites, HIV does not survive or reproduce in insects. Thus, even if the virus enters a mosquito or another insect, the insect does not become infected and cannot transmit HIV to the next human it bites. Moreover, when a mosquito bites a person, it does not inject its own or a previously bitten person's or animal's blood into the next person. Rather, it injects saliva, which acts as a lubricant so the insect can feed efficiently.

What is the best way to prevent HIV infection?
Abstinence and mutually faithful sexual relations are the best guarantee for preventing sexual transmission of HIV. Use of sterilised needles is also important.

Is it true that male circumcision may provide protection against HIV infection?
Recent studies in Africa that have shown that circumcision can reduce HIV infection. However, these studies are being debated as they show conflicting evidence: in some age groups circumcision reduced HIV infections, in other age groups it was associated with increased HIV. Circumcision done under unsterile conditions may also increase the risk of HIV transfer. Scientists looking at male circumcision and female genital mutilation (FGM) practices in Kenya, Lesotho and Tanzania found that the cut in itself was causing many new AIDS cases among adolescents.

(Compiled by Mariette Correa, an independent consultant who has been involved in HIV/AIDS programming for NGOs in Goa and South Asia)

InfoChange News & Features, February 2008