The human immunodeficiency virus (HIV) is a retrovirus (Retroviridae family) that contains RNA and affects the immune system by attacking CD4+ T-lymphocytes, macrophages and dendritic cells. There are two types of HIV distinguished – HIV-1 and HIV-2. HIV-1 is more common, whereas HIV-2 is mainly found in West Africa.
HIV infection is a sexually transmitted disease, so no wonder that more than half of the cases of HIV contraction are associated with sexual intercourse.
- Sexual transmission (male-to-male sexual contact, heterosexual contact –unprotected vaginal or oral sex);
- Transmission by blood and blood products (injection drug use, blood transfusions, blood products or organ transplantation, direct contact between wounds, broken skin or mucous membranes and infected blood, blood-contaminated body fluids or other infected body fluids, reused or not properly sterilized needles or other equipment used for piercing or tattoo);
- Occupational transmission (injuries with needles of sharp medical instruments);
- Maternal-fetal/infant transmission during pregnancy, vaginal delivery, or breastfeeding);
Prevention of HIV is based upon the actions that affect that modify the ways of HIV transmission.
Only abstinence can provide 100% protection against HIV. However, the condom may effectively protect against HIV as well.
Having one partner and avoiding accidental sexual intercourses is associated with a lower risk of HIV. Make sure that both you and your partner do not have HIV.
When your partner is HIV-positive you should be tested for HIV regularly. He/she should receive antiretroviral therapy to postpone the development of AIDS and reduce the viral load in the body fluids.
Preexposure and postexposure prophylaxis
Preexposure prophylaxis is an everyday administration of the medicines by a person who has a risk of getting HIV before the exposure. A combination of tenofovir and emtricitabine (Truvada) is known to decrease the risk of HIV contraction from sexual intercourse by 90% and from sharing needles – by 70%.
Postexposure prophylaxis should be initiated within 72 hours after the exposure. Antiretroviral medications (lopinavir/ritonavir and lamivudine/zidovudine or emtricitabine/tenofovir) should be taken once or twice a day for at least 28 days. Afterwards a person should be tested for HIV. The next test is performed 3 months and 6 months later.
Injection drug use
Drug abuse is associated with higher prevalence of HIV than in the general population. According to the CDC, about 7% of HIV positive persons were infected by injection drug use in the USA and about 10% – worldwide.
Injection drug use should be avoided to diminish the risk of HIV infection. If a person uses injection drugs it is recommended to:
- Avoid sharing needles, syringes and other injection equipment with others;
- Use new sterile needles and syringes. In some countries, there are established syringe services programs/ syringe exchange programs or needle exchange programs where you can get sterile syringes for free;
- Use alcohol swab to clean your skin before injections;
- Use sterile water to mix drugs;
See also: Signs and symptoms of HIV
Prophylaxis of mother-to-child transmission
A pregnant woman should receive antiretroviral treatment (ART) no matter what is the viral load.
All HIV-infected women with HIV RNA >1,000 copies/mL near delivery should receive zidovudine intravenously during labor at a dose of 2 mg/kg, followed by an infusion of 1 mg/kg throughout labor. If the cesarean delivery is planned, the infusion should begin 3 hours before the procedure. C-section is considered for woman who has a viral load of more than 1000 RNA copies/mL.
All neonates who were exposed to HIVs should receive zidovudine during the first six weeks after they were born:
- < 30 weeks’ gestation: 2 mg/kg BID; after age 4 weeks – 3 mg/kg BID;
- >30 to < 35 weeks’ gestation: 2 mg/kg BID; after age 2 weeks – 3 mg/kg BID;
- >35 weeks’ gestation: 4 mg/kg BID;
Additional nevirapine (for infants of women who did not receive ART during pregnancy):
- Birth weight 1.5-2 kg: 8 mg/dose;
- Birth weight >2 kg: 12 mg/dose;
It is better to avoid breastfeeding when a child has not been infected before. Replacement feeding is recommended. Exclusive breastfeeding until the age of 6 months with early cessation when formula milk is not available. Wet-nursing by a non-infected woman may be an option as well. Breast feeding should be ceased when there are any signs of breast inflammation or nipple lesions. For premature infants breast milk may be pasteurized – such milk is considered to be safer for consumption.