Sunday, August 9, 2015

Why are women at higher risk of contracting HIV?

Women’s Day Awareness Article
By Alan Brand - Positively Alive - 09 August 2015

In this fact sheet we review specific biological factors in women that make it more or less likely that HIV can be sexually transmitted.

Fast Facts
  •          It is estimated that 12.2% of the South African population (6.4 million persons) are HIV positive. This is 1.2 million more People Living with HIV than in 2008 (10.6%, or 5.2 million). The main route of HIV transmission is through heterosexual sex.
  •         HIV prevalence in young women 20 - 24 is at 17.4% which is three times higher than in men of the same age, 5.1%. Within the 25 - 29 year age group HIV prevalence amongst women is 28.4% whilst in men of the same age group it is 17.3%.
  •         Only 43.5 per cent of male youth (aged 15-24 years) and 40.6 per cent of females of the same age group can correctly identify ways to prevent sexual transmission of HIV and reject major misconceptions about HIV transmission.
  •         Women (especially young women and girls) face increased risks of HIV infection, these calls for more effective enabling interventions. Risk-enhancing factors include alcohol abuse, violence against women and socioeconomic insecurity there are many people accessing ARVs which has a huge impact on available domestic resources.

Before we explore why genetically women are more at risk of HIV transmission, lets first look at some important basic information on HIV transmission in general.

How does HIV infection occur?
For infection to occur two things must happen.
·         The virus must find a way to enter your bloodstream.
·         The virus must “take a hold” (find a T/cell with a CD4 and CCR5 receptor which the virus needs to enter the body’s cells) 

Think of it with the word SAD
S = Sufficient quantities of the virus
A = Access into the body
D = Duration

There must be sufficient quantity of the virus to infect you, and it must enter your body in an efficient manner, and their needs to be enough time for this to happen.

There are only three ways in which this can happen:
·         Unprotected sexual acts with an infected person
·         Through infected blood e.g. in sharing needles
·         Prenatally from mother to child during pregnancy or at birth, and through breast milk.

Body fluids!
Body fluids can be divided into those, which contain sufficient quantities of the virus to be infectious. These are:
Blood (100% if HIV Viral load present)
Semen (75% if HIV Viral load present)
Vaginal secretions (50% if HIV Viral load present)
Breast milk (Low but still possible with prolonged breast feeding if HIV Viral load present)

For transmission of HIV to happen, body fluids infected with the virus must pass from the already infected person into the bloodstream of another. HIV can do this through contact with the thin linings of various openings in the body and openings in the skin. These linings contain concentrations of the cells to which HIV attaches to enter the body. The sexual organs of both men and women have such linings.

This is why unprotected sexual acts are the most common route for HIV transmission. The chance of transmission is greatly increased if the lining or skin is inflamed or damaged, for example when another sexually transmitted disease is present.

On the other hand there are other body fluids, which do not contain sufficient quantities of the virus to be infectious.  These are:
How do you get HIV?
  • Infection through sexual practices.
    • Semen / vaginal fluid coming into contact with the thin linings of various openings in the body and openings in the skin.
  • Infection through blood. (Blood products)
    • Intravenous drug users.
    • Blood transfusions. (Since 1985 all blood is tested for HIV)
    • Needles, ear piercing, razor blades, dental tools, (unsterilized)
  • Infection from mother to child.
    • Across the placenta: - during pregnancy.
    • During birth:  damaged lining/skin
    • Breast milk:
So why are women at greater risk of HIV?
The risk of transmitting HIV from men to women is much higher than from women to men. This is in part because of the much larger surface area of the vagina and cervix compared to the areas of the penis where transmission can happen (foreskin, urethra and small tears on the head of the penis).

Women are exposed to considerable amounts of seminal fluid during sex, if ejaculation occurs.

The vagina is particularly vulnerable to invasion by bacteria, viruses and other germs. It is an ideal place for bacteria to grow, as it is warm and moist. It also provides an easy entrance into the body.

Women with low levels of the hormone oestrogen may be at increased risk for transmission of HIV because low oestrogen levels directly affect the vaginal wall, making it thinner so HIV can more easily pass through the wall.

How does HIV get into the body through the female genital tract?
The vagina has various defence mechanisms against infection. These help to protect a potential foetus developing in the uterus.

The walls of the vagina are made up of mucous membrane that is thicker than the mucous membrane in other places where HIV transmission often happens, such as the rectum or cervix.  The walls of the vagina have ten to twelve overlapping layers of epithelial cells, which create a strong barrier against germs such as viruses and bacteria.

The vagina is also home to a number of “friendly” bacteria species (for example, Lactobacilli) which are thought to give some protection against less friendly bacteria (for example, Gardnerella vaginalis) as well as viruses that might infect the body.

It used to be thought that HIV can only get through the walls of the vagina through small tears or sores in the mucous membrane. Recent research suggests that HIV can pass between or through healthy cells. This means that HIV can still infect women even if the vaginal mucous membranes are healthy and intact.

Unlike the vagina, the mucous membranes lining the cervix and uterine walls have only a very thin layer of cells (often just one layer thick) and so it is much easier for viruses like HIV to cross into the body through the cervix and possibly the uterus.

Because the cervix acts as a barrier to protect a potential foetus, it is home to a large number of immune cells. Many of those immune cells are CD4+ cells, which are the cells that HIV is most able to infect.

What about sexually transmitted infections?
Women are at more risk for sexually transmitted infections (STIs) than men. In addition, women often have fewer obvious symptoms, and therefore don’t get treatment until the infection has been present for a long time. 

Having an STI increases the risk of HIV transmission in several ways:
  •         All STIs cause inflammation of the mucous membrane. Inflammation is the body’s immune response to an infection or irritation. When the mucous membrane is inflamed, a large number of immune cells come to the area to fight the infection.
  •         Many of those immune cells will be CD4+ cells or other immune cells that are involved in HIV transmission. In addition, when cells are fighting off an infection, they become activated. Activated CD4+ cells are more easily infected by HIV.
  •         Some STIs also cause open lesions or sores, which offer an easy way for the virus to get into the body and cause an infection.

Why are women at higher risk of being affected by HIV?
·         Some women may be unaware of their male partner’s risk factors for HIV (such as injection drug use or having sex with other men) and may not use condoms.
      The risk of getting HIV during vaginal sex without a condom or other protection such as PrEP is much higher for women than it is for men, and anal sex without a condom or PrEP is riskier for women than vaginal sex without a condom or PrEP.
      Women may be afraid that their partner will leave them or even physically abuse them if they try to talk about condom use.
      Some sexually transmitted diseases (STDs), such as gonorrhoea and syphilis, greatly increase the likelihood of getting or spreading HIV.
      Women who have been sexually abused may be more likely than women with no abuse history to engage in sexual behaviours like exchanging sex for drugs, having multiple partners, or having sex with a partner who is physically abusive when asked to use a condom.
      Some HIV infections among women are due to injection drug and other substance use—either directly (sharing drug injection equipment contaminated with HIV) or indirectly (engaging in high-risk behaviours while under the influence of drugs or alcohol).

What is “SAFER SEX”?
“Safer Sex” Means: - Sexual practices, which involve the use of condoms for penetrative anal or vaginal sex, and the use of many different forms of experiencing sexual pleasure without placing people at risk of HIV transmission.

Always talk to your regular or potential sexual partner about safe sex.
Alan Brand

Employee Wellness Consultant and Specialist HIV and Employee Wellness Training Provider

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