TRANSMISSION OF HIV
HIV is a weak virus that cannot survive without a human host and that is not spread by casual contact. HIV is transmitted from one person to another only through contact with certain body fluids, and transmission is only possible if these fluids come in contact with mucous membranes or damaged tissue, or are directly injected into the bloodstream (e.g., from a needle or syringe). Mucous membranes are located in the rectum, vagina, opening of the penis, and mouth (USDHHS, 2020; CDC, 2019b).
HIV can only be transmitted through the following body fluids:
- Blood
- Semen
- Preseminal fluids
- Rectal fluids
- Vaginal fluids
- Breast milk
In addition, any bodily fluid visibly contaminated with blood should be considered capable of transmitting HIV. Such fluids may include:
- Cerebrospinal fluid
- Amniotic fluid
- Pleural fluid
- Synovial fluid
- Peritoneal fluid
- Pericardial fluids
Unless blood is visibly present, HIV cannot be transmitted by:
- Saliva
- Sputum
- Sweat
- Tears
- Feces
- Nasal secretions
- Urine
- Vomitus
Other than those described above, HIV cannot be transmitted by:
- Air
- Water
- Closed-mouth kissing
- Insects
- Pets
- Sharing food or drinks
(Waseem, 2019; CDC, 2019b)
Sexual Contact
Anal sex is the riskiest type of sex for getting or transmitting HIV. Receptive anal sex is greater risk than insertive anal sex. However, the insertive partner is also at risk because HIV can enter the body through the urethra (CDC, 2019b).
In extremely rare instances, HIV has been transmitted through oral sex. For the most part, there is little to no risk of getting HIV from oral sex, but transmission of HIV is theoretically possible if an HIV-positive man ejaculates into his partner’s mouth during oral sex (CDC, 2019b).
Injection Drug Use
HIV can live in blood inside a used needle for up to 42 days depending on the temperature and other factors. Sharing injection needles, syringes, and other paraphernalia with an HIV-infected person can send HIV (along with hepatitis B and C viruses and other bloodborne diseases) directly into the user’s bloodstream. Paraphernalia with the potential for transmission include the syringe, needle, “cooker,” cotton, and/or rinse water (sometimes called “works”) (CDC, 2019b).
Transfusion
Due to careful donor selection criteria, it is very rare for HIV to be transmitted through a blood transfusion. However, despite the precautions, it may still occur. Theoretically there are three reasons; however, only the first has been documented to have occurred:
- Donations may be collected during the window period of infection, which is the interval of time after the donor becomes infected with HIV and before the development of detectable antibodies.
- Infection may occur from variant strains of HIV that may escape detection by current screening assays.
- Testing or clerical errors may occur.
(Silvergleid, 2019)
Perinatal
The use of HIV medications and other strategies have led to a lowered incidence of mother-to-child transmission of HIV to 1% or less in the United States and Europe. However, despite continued use of HIV medicines after childbirth, a woman with HIV can still transmit HIV to her child while breastfeeding (USDHHS, 2020).
Occupational Exposures
Since 1985 there have been 58 confirmed and 150 possible cases of occupationally acquired HIV infection among healthcare workers. Since 1999, only one confirmed case has been reported (CDC, 2019c).
Risk for occupational HIV transmission varies by the type of exposure and is increased when the source has a high viral load, the volume is large, and the exposure is deep. Healthcare personnel at highest risk of transmission are those who have been inoculated percutaneously with blood from a source patient with HIV who is not on suppressive antiretroviral therapy and/or has a detectable viral load (Zachary, 2019).
OCCUPATIONAL INFECTION CONTROL
The state of Florida requires training in Standard Precautions, which are used to prevent HIV transmission in healthcare settings. Standard Precautions are used with all patients at all times and in all settings and include:
- Personal protective equipment including gloves, masks, protective eye wear, face shields
- Hand hygiene using soap and water or waterless, alcohol-based hand rub
- Careful handling and disposal of sharp instruments during and after use
- Use of tags or labels to indicate biohazardous material
- Control of personal activities in the workplace (e.g., eating, drinking)
Additionally, the Occupational Safety and Health Administration (OSHA) standards for bloodborne pathogens (BBP, 29 CFR 1910.1030) and personal protective equipment (PPE, 29 CFR 1910 Subpart I) require employers to protect workers from occupational exposure to infectious agents (OSHA, n.d.).
When occupational exposure to HIV occurs, the U.S. Public Health Service recommends that the status of the exposure source patient be obtained and postexposure prophylaxis medication be started within 72 hours and continued for a four-week duration. Expert consultation is recommended, and close follow-up should be provided with baseline and follow-up HIV testing (Kuhar et al., 2018).
| Type of Exposure | Risk per 10,000 Exposures |
|---|---|
| (CDC, 2019e) | |
| Parenteral | |
| Blood transfusion (with infected blood) | 9,250 |
| Needle-sharing during injection drug use | 63 |
| Percutaneous (needle-stick) | 23 |
| Sexual | |
| Receptive anal intercourse | 138 |
| Insertive anal intercourse | 11 |
| Receptive penile-vaginal intercourse | 8 |
| Insertive penile-vaginal intercourse | 4 |
| Receptive oral intercourse | Low |
| Insertive oral intercourse | Low |
| Other | |
| Biting | Negligible |
| Spitting | Negligible |
| Throwing body fluids (including semen or saliva) | Negligible |
| Sharing sex toys, razors, toothbrushes | Negligible |
| * There may be a relatively small chance of acquiring HIV when engaging in a risk behavior with an infected partner only once; but, if repeated many times, the overall likelihood of becoming infected after repeated exposures is much higher. | |