Understanding the causes of HIV is crucial to preventing new infections and addressing the global impact of the virus. HIV (Human Immunodeficiency Virus) spreads primarily through specific bodily fluids and attacks the immune system, especially CD4 T cells.
How HIV Is Transmitted
The most common causes of HIV transmission include:
1. Unprotected Sexual Contact
HIV is most frequently spread through vaginal, anal, or oral sex without a condom. Receptive anal sex carries the highest risk due to fragile rectal tissue. Vaginal sex also poses significant risk, especially for women, due to biological susceptibility. Consistent and correct condom use greatly reduces this risk.
2. Sharing Needles or Syringes
People who inject drugs and share contaminated needles risk direct HIV transmission into the bloodstream. Needle sharing remains a major cause in some communities lacking harm-reduction programs. Clean needle access and addiction treatment reduce this transmission route.
3. Mother-to-Child Transmission (Vertical Transmission)
An HIV-positive mother can pass the virus during pregnancy, childbirth, or breastfeeding. Without intervention, transmission risk is significant. However, antiretroviral therapy (ART) during pregnancy and delivery plus alternatives to breastfeeding reduce this risk to under 1%.
4. Blood Transfusions and Organ Transplants
Though rare today due to strict screening, contaminated blood or organs remain a possible cause in areas with limited healthcare infrastructure. In the past, before HIV was understood, transfusions were a significant transmission source.
5. Occupational Exposure
Healthcare workers may be exposed through accidental needle sticks or contact with infected blood on broken skin. Post-exposure prophylaxis (PEP) effectively prevents infection if given promptly.
6. Tattooing and Body Piercing
Using unsterilised equipment during tattooing or piercing, especially in informal settings, can transmit HIV. Although less common, poor hygiene in body art practices poses a risk alongside hepatitis B and C.
Biological Mechanisms and Viral Load
HIV infects the body by binding to CD4 cell receptors, allowing viral entry and replication. The viral load—the amount of HIV in bodily fluids—affects infectiousness. People with high viral loads transmit HIV more easily, while those on ART with undetectable viral loads cannot sexually transmit the virus. This is the foundation of the U=U (Undetectable = Untransmittable) message.
What Does NOT Cause HIV
HIV cannot be transmitted by:
- Casual contact (hugging, shaking hands, kissing)
- Sharing food, drinks, or toilet seats
- Insect bites
- Air or water
These myths contribute to stigma and discrimination, which hinder HIV prevention and treatment efforts.
Social and Structural Causes
The causes of HIV are not only biological but also deeply social. Factors increasing risk include:
- Poverty and lack of healthcare access
- Gender-based violence
- Discrimination against key populations (e.g., men who have sex with men, sex workers, people who inject drugs)
- Criminalisation of behaviours linked to HIV transmission
Addressing these social drivers is vital to reduce HIV spread.
Role of Education
Comprehensive sex education covering safer sex, consent, and prevention tools like PrEP (Pre-exposure Prophylaxis) lowers infection rates, especially in youth. Unfortunately, cultural and religious taboos restrict education in many areas, leaving populations vulnerable.
Origins of HIV
HIV originated in the early 20th century from zoonotic spillover:
- HIV-1 from chimpanzees in Central Africa
- HIV-2 from sooty mangabeys
Humans contracted the virus through hunting and consuming infected animals. While no longer a modern transmission concern, this history highlights the importance of monitoring zoonotic diseases.
Conclusion
The causes of HIV are well understood by the people, yet preventing new infections requires more than medical knowledge. It demands education, harm reduction, universal testing and treatment access, and combating stigma and inequality. Using condoms, clean needles, ART, and PrEP, people can prevent most HIV transmissions. Tackling biological and social causes is key to an HIV-free future.
