# HIV --- **HIV** stands for **human immunodeficiency virus**, and it is a deadly [[animal virus|virus]] that attacks and weakens our [[immune system]] (specifically our [[helper T-cells]]), and if left untreated eventually causes a condition called **acquired immunodeficiency syndrome**, or **AIDS**. Although AIDS is absolutely fatal if left untreated, with anti-retroviral treatment the life expectancy for someone HIV positive is not the same as anyone else. >[!person] AIDS Stigma >When AIDS first came into public awareness, it largely and almost exclusively affected gay men, which led to it being largely ignored and stigmatized in the government and healthcare industry. Whole communities were wiped out with little to no aid or support. Although we have come very far as a culture, this part of the AIDS story should not be overlooked or forgotten. HIV is transmitted though direct contact with infected bodily fluids such as: - blood - semen - pre-seminal fluid - vaginal fluids - rectal fluids - childbirth - breastmilk Indirect transmission is possible, such as with the reuse of intravenous needles, but it does not transmit though skin-to-skin contact or even kissing. ## The HIV Virus HIV can [[virulence#The Ability to Evade Host's Adaptive Defense|evade our adaptive defenses]] by forming a [[virulence#The Ability to Evade Host's Adaptive Defense|syncytium]] and running around rampant invisible to our [[antibodies]]. The asymptomatic period is when HIV multiplies in lymph nodes without showing symptoms and can last a few months up to 10 years. There are actually two types of HIV, HIV-1 and HIV-2 characteristics | HIV-1 | HIV-2 ---|---|--- **invectivity** | high | low **virulance** | high | low **heterosexual spread** | higher | lower **vertical transmission** | 20-25% | <5% **genetic diversity** | - | lower **prevalence** | global | West Africa **origin** | Common Chimpanzee | Sooty Mangabey **time to AIDS** | < 10 years | >20 years ## Stages of Infection HIV goes through a progression that takes place over years. Without an anti-retroviral the viral load builds up over about 10 years. Although the stages are progressive, if there is any time an opportunistic infection—or an **AIDS defining infection**—it is considered to be AIDS. One measurement followed closely and used to stage HIV progression is helper T-cells, or the [[helper T-cells|CD4 cells]]. These are the cells that the virus uses to infect. While the number starts out pretty high, over time it dwindles and dwindles until there are very few left. ![[HIV progression.png]] - **Stage 1** - CD4 count >500 cells/uL *and* no AIDs-defining condition - during this time there is *rapid viral replication* and dissemination - high viral load - there are flu-like symptoms for 1-4 weeks - antibodies form at detectible levels 2-4 weeks after exposure - this is called **seroconversion**, although that term is not exclusive to HIV - after seroconversion, HIV antibody tests will be positive >[!biology]- HIV seroconvesion graph >![[HIV seroconversion.png]] - **Stage 2** - CD4 count of 200-499 cells/uL *and* no AIDS-defining condition - there is variable progression during this stage - progression depends largely on if someone is on antiretroviral medication - the viral load is increasing and CD4 count is decreasing - weakened immune response - there may be mild symptoms or asymptomatic - **Stage 3** or [[AIDS]] - CD4 count <200 cells/uL *or* an AIDs-defining condition - multiple severe opportunistic infections - cancers - wasting syndrome - CNS involvement - this stage is in itself progressive - there is an increasing viral load and low CD4 count ### Tests to Monitor HIV Progression - CD4 (T-Cell) Count - Normal 500-1600 cells/L - CD4-to-CD8 Ratio - Normal: 2:1 - Viral Culture - Measures Reverse Transcriptase - this helps viral RNA incorporate into the cell - Viral Load Testing - NAT ## Prevention There are two main therapies for preventing getting HIV: **PrEP** for use by people who are at high risk of contracting HIV and **PEP** for those who are HIV- but may have been exposed ### PrEP **PrEP** stands for **pre-exposure prophylaxis**, and is used *before* potential exposure to HIV, usually taken by people who are at high risk--either from sex or from injection drug use. PrEP consists of two pills taken daily, and can reduce the risk of getting HIV from sex by about 99% and from injection drug use by at least 74%. - **PrEP** meds - **Truveda** (combo med) - all people who are at risk - **Discovy** - penis-havers who are at risk through sex ### PEP **PEP** stands for **post-exposure prophylaxis**, taken by HIV- people after a HIV exposure or suspected exposure. It can be used if taken within 72 hours (3 days) after the possible exposure (i.e. unprotected sex, sharing needles/accidental needlestick/etc.). PEP can prevent HIV when taken correctly, but it's not necessarily always effective. The best chance of it working is if you start it as soon as possible after the exposure. - **PEP** meds - Three medications, taken for 28 days: - **Tenofovir** - **Emtricitabine** - Either **Raltegravir** or **Dolutegravir** ## Diagnostic Tests There is no test that can confirm HIV directly after the exposure. There is a window period before seroconversion happens that there's just no way to tell. If there has been an exposure, it's important to just start PEP right away. If you take a rapid test and it's negative, but you still suspect you've been exposed, you should wait till the window period has elapsed and then re-test. If a rapid test is positive, you should follow it up wiht a viral load test. - **Nucleic Acid Tests** (NAT) - Tests the viral load directly - Early detection, but that still means 10-33 days post exposure - Quite pricy - only done if there are symptoms or a known exposure - **Antigen/Antibody Tests** - Tests for the presence of a specific antigen (p24) & its antibody - It is the more common rapid test - 18-45 days post exposure (vein) - 18-90 days (finger prick) - **Antibody Tests** - Only look for the IgM and IgG antibodies - Blood, oral fluid - Only currently approved self-test - 23-90 days post exposure ## Treatment Treatment for HIV is called [[highly active antiretroviral therapy]], or simply **antiretroviral therapy**, does not cure it, but it *can* reverse the loss of immune function. The goals of treatment are: - decreasing viral load - restoring/improving immune function - prevent/treat opportunistic infections - improve overall quality of life - reduce the incidence of illness/death from [[AIDS]] ## HIV in Pregnancy • Treatment has advanced greatly • <1% risk of vertical transmission to baby if viral load is kept low • Vaginal birth is no longer contraindicated if viral load is low • Breastfeeding still not recommended ![[HIV in pregnancy.png]] ___