HIV Causes and Risk Factors

HIV is a disease that many people know little about. Here we show you what causes it, its risk factors, and prevention tips.
HIV Causes and Risk Factors

Last update: 17 August, 2021

According to the World Health Organization (WHO), 690,000 people died of HIV in 2020, with an average of 1.5 million being infected for the first time. So far, the virus is estimated to have claimed nearly 35 million deaths worldwide. Understanding the causes and risk factors of HIV is part of the prevention process.

Despite all the awareness campaigns, prejudices and misinterpretations regarding the infection still persist. Today, we’ll be answering all the questions you have about its transmission mechanism, as well as some tips that you should take into account to avoid contagion.

What are the causes of HIV?

The human immunodeficiency virus (HIV) is a retrovirus. More specifically, a lentivirus that destroys certain white blood cells in the body. This causes a weakening of the immune system and, in turn, exposure to infections and cancer. When it’s transmitted to a person’s body, they’re said to have HIV infection.

Infections are caused by two specific retroviruses: HIV-1 and HIV-2. Most of the cases reported worldwide correspond to the former, although the latter is highly prevalent in West Africa. According to the researchers, HIV-1 has a higher mortality rate than the second variant.

Once in the body, the virus progressively destroys CD4 + lymphocytes. This means that, over the years, patients develop a greater vulnerability to infections. In fact, most HIV deaths aren’t caused by the virus itself, but by complications.

The spread of the virus around the world began during the 1970s and the first cases of AIDS were reported in 1981. Since then, many theories about its origin have emerged. Recent research confirms that it’s a mutation of the simian immunodeficiency virus (SIV) that affects some species of chimpanzees in Central Africa.

If the infection isn’t treated, the patient will develop acquired immunodeficiency syndrome (AIDS). As the Centers for Disease Control and Prevention (CDC) reminds us, this is the last stage of infection and, in the absence of therapy, the average life span is around three years.

Human immunodeficiency virus HIV.
The virus that causes AIDS has two varieties. One of them is predominant in most of the world.

How is HIV transmitted?

We have already pointed out that the causes of HIV are two types of retroviruses. It is time, then, to describe how you can be infected.

The virus is spread by exchanging bodily fluids with an infected person. This includes semen, vaginal secretions, breast milk, and blood.

Sexual contact

You can become infected with HIV through contact with the virus with the lining of the vagina, penis, rectum, or mouth, as Johns Hopkins Medicine reminds us. Most people believe that contagion is only possible through anal sex. Although it’s true that the lining of the rectum is more sensitive, as the CDC points out, vaginal infections are possible.

There’s also a slight difference between the performer and the receiver of the act. From a statistical point of view, the latter have higher risks of contagion.

Both men and women can get the infection. In fact, today the percentage of men and women infected with HIV is very similar. For example, by 2015, UN Women estimated that 51% of cases were female.

Mother-to-child transmission

According to WHO data, there’s a 15% to 45% risk of the virus infecting the baby in an HIV-positive mother. This is if you aren’t receiving treatment. When there’s treatment, the risk decreases to less than 5%. The contagion can take place during the development of the fetus, in labor, or in lactation.

Most cases of HIV in children are due to this type of transmission. All pregnant women should get tested for HIV. Treatment begins around the second trimester of pregnancy and continues throughout breastfeeding.

Blood and needle transfusions

Channels of transmission through blood represent a huge challenge in many countries. Blood transfusions with HIV are very rare today, as analysis mechanisms are available to determine if the donor’s blood is infected.

Even so, several cases are reported annually around the world, mainly in particularly vulnerable regions. Sharing contaminated needles or syringes, as is common in recreational drug use, is also a direct channel of contamination.

Non-disinfected tattoo needles, piercings etc, all increase the risk of transmission through infected blood.

How is HIV not transmitted?

We’ve described the main channels through which you can get HIV. As Stanford Health Care does well to remind us, the virus cannot be transmitted in the following contexts:

  • Cuddling or hugging
  • Exchange of sweat, saliva, or tears
  • Sharing objects with infected people (clothes, towels, mobile phones)
  • Vector insects (such as mosquitoes)
  • Toilet seats
  • Swimming pools
  • Food handled by people with HIV

If you have been diagnosed with a sexually transmitted disease (STD), you have a greater chance of contracting or transmitting the virus, although not through the previous routes. In short, the causes of HIV are related to a retrovirus that is transmitted through sexual encounters, direct contact with infected blood, and during childbirth or breastfeeding.

How to prevent HIV

Based on the above, we can determine the way to prevent infection. UNAIDS recommends the following:

  • Use male or female condoms in every sexual encounter
  • Reduce the number of sexual partners you have
  • Get circumcised
  • Use sterile needles and injectors in any setting
  • Start opioid substitution therapy
  • Learn about the prevalence of the disease in the region

Although these considerations reduce the chances of infection, the United Nations program suggests that these alone can’t end the epidemic. As we already indicated, mothers should undergo tests to avoid passing on the virus if they’re carriers.

Condom to prevent the causes of HIV.
Condom use is essential to stop the spread of HIV.

Frequently asked questions about the causes of HIV

We’ll finish this section on the causes of HIV by answering a set of questions about the infection.

1. Can HIV be transmitted through oral sex?

Yes, studies in this regard confirm that the infection can be transmitted through oral sex with infected people. The risk, however, is lower than having anal or vaginal sex.

2. Where in the body is the infection found?

Viruses can be found in all body fluids. However, its prevalence is higher in semen, vaginal fluids, blood, and breast milk.

Research indicates that more than 90% of the virus is destroyed in saliva, so infections from salivary fluid exchanges are highly unlikely. In fact, there’s no evidence whatsoever that it’s possible.

3. Can latex condoms prevent infection?

Used correctly, condoms can reduce the chances of infection by more than 90%. Despite this, however, it isn’t an infallible method.

4. Can I get infected if I share razors?

Yes, contact with any type of tool that has traces of blood from an infected person poses a risk of contagion. This includes knives, pocket knives, and syringes.

  • Baron S, Poast J, Cloyd MW. Why is HIV rarely transmitted by oral secretions? Saliva can disrupt orally shed, infected leukocytes. Arch Intern Med. 1999 Feb 8;159(3):303-10.
  • Hawkins, D. A. Oral sex and HIV transmission. 2001.
  • Sharp PM, Hahn BH. Origins of HIV and the AIDS pandemic. Cold Spring Harb Perspect Med. 2011 Sep;1(1):a006841.
  • Whittle H, Morris J, Todd J, Corrah T, Sabally S, Bangali J, Ngom PT, Rolfe M, Wilkins A. HIV-2-infected patients survive longer than HIV-1-infected patients. AIDS. 1994 Nov;8(11):1617-20.

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