HIV can be transmitted through contact with certain bodily fluids infected with the virus including blood, semen, rectal fluid, breast milk, vaginal fluid, and pre-seminal fluid. Engaging in behavior that involves contact with these fluids such as unprotected vaginal or anal sex or sharing syringes with someone who is HIV positive increases the risk of HIV transmission.

People who have unprotected sex or share needles should ensure that they get tested for HIV at least once a year. Sexually active men who are bisexual or gay may benefit from testing more frequently, every 3 to 6 months, for example.

The Centers for Disease Control and Prevention advises that anyone between the ages of 13 and 64 receives an HIV test at least once as part of routine healthcare, irrespective of their perceived risk status. This is because one in six people who are HIV-positive in the US are not aware that they have the infection.

Key Risk Factors

Although risk factors for HIV transmission are the same for everyone, certain groups of people are more affected by HIV compared to the rest of the population. These are described in more detail below.

• Race and ethnicity: There may be higher rates of HIV in a particular racial or ethnic community due to factors such as education, stigma, or discrimination.

• Gender and sexual orientation: The risk of HIV transmission can vary with gender and sexual orientation. For example, the rate of HIV transmission in the US is highest among men who have sex with other men, even though this group only makes up 2% of the population.

• Age: Certain age groups are associated with an increased risk of HIV transmission. In the US, the incidence of HIV infection is on the increase among young men who have sex with other men and particularly among black men who engage in sex with males aged between 13 and 24.

Reducing HIV risk

There are several measures people can take to reduce their risk of transmitting HIV and some of these are described below.

Engage in lower risk sexual behavior

The most common ways by which HIV spreads is through unprotected vaginal or anal sex. Anal sex is associated with the greatest risk of HIV transmission. Either of the partners can transmit HIV this way, but the risk of passing the virus on to an HIV negative person is much greater if that person is the receiver.

Unprotected vaginal sex is also risky, although the likelihood of transmission is less likely than with anal sex. In the case of oral sex, the risk of transmission is little to none.

Use condoms

When condoms are used consistently and properly, they can be highly protective against HIV transmission.

Reduce the number of sexual partners

The risk of HIV transmission increases with the number of sexual partners a person has. The more partners a person has, the greater the likelihood that they will engage in sex with someone who has an unsuppressed level of HIV in their body (viral load) or another sexually transmitted disease (STD), both of which are risk factors for transmitting HIV.

Consider pre-exposure prophylaxis

Pre-exposure prophylaxis is a treatment people can take, in tablet form, if they are at a considerable risk of transmitting HIV. Research has demonstrated that this type of therapy is highly effective when it is taken consistently and as instructed. Examples of people who may be prescribed this therapy include the following:

• An HIV-negative person who is in a relationship with a partner who has HIV
• Individuals not in a monogamous relationship with an HIV-negative partner and who are also bisexual or gay and have engaged in unprotected anal sex or been diagnosed with an STD in the previous six months
• Individuals not in a monogamous relationship with an HIV-negative partner who are also heterosexual but do not always use condoms while engaging in sex with partners of unknown HIV status who are at a very high risk of having the infection.

Get a test for other STDs

Sexually active individuals should ensure that they get tested and treated for any other STDs and encourage their partners to also do this.

People should undergo an STD check at least once a year because these diseases can have long-term effects on health and also increase the risk of HIV transmission.

Encourage an HIV-positive partner to adhere to medication

If a person has a partner who is HIV-positive, they should encourage that person to adhere to any treatment prescribed. Antiretroviral therapies (ARTs) reduce the level of HIV in the body and if these medications are taken properly and consistently, the risk of transmission to an HIV-negative partner is significantly reduced.