AIDS (HIV): Prevention

For the prevention of HIV infection, the following protective factors are important; furthermore, attention must be paid to reducing individual risk factors. Relative protective factors

  • Circumcision (circumcision) for non-HIV-infected men-mitigation of HIV transmission risk by:
    • Removal of the prepuce (foreskin, which, unlike the glans penis (glans), is abundant with cells that are targeted by HIV. These are Langerhans cells of the skin, CD4-positive lymphocytes (CD4 receptor site of T helper cells) and macrophages (phagocytes).
    • Risk reduction for genital ulcers (genital ulcer).

Behavioral risk factors

  • Drug use (intravenous, i.e., through the vein).
  • Needle sharing – sharing needles and other injection equipment among drug abusers.
  • Unprotected intercourse – unprotected anal intercourse is the highest risk practice for both individuals (receptive 0.82% per contact; insertive 0.07% per contact); unprotected vaginal intercourse is considered the second highest risk route of infection.

Disease-related risk factors

  • Immunocompromised individuals
  • Patients with a sexually transmitted infection (STI), such as gonorrhea (gonorrhea) or syphilis (syphilis), have a 2-10-fold higher risk of HIV transmission from an HIV-positive person (due toSTI-related lesions or ulcers/vulcers); likewise, an HIV-positive patient with an STI is more contagious (infectious).

Other risk factors

  • Blood products
  • Horizontal transfer – from mother to child at birth.
  • Needlestick injuries – especially among health care workers.
  • Organ transplants

Prevention factors (protective factors)

  • Genetic factors:
    • Genetic risk reduction depending on gene polymorphisms:
      • Genes/SNPs (single nucleotide polymorphism; English : single nucleotide polymorphism):
        • Gene: CCR5
        • SNP: rs333 in gene CCR5
          • Allele constellation: DI (low risk of infection to HIV and slower progression) (15% of Europeans have this allele constellation).
          • Allele constellation: DD (resistance to HIV-1) (1% of Europeans have this allele constellation).
        • If both CCR5 gene copies are mutated (= homozygous), affected individuals have a 21% increased mortality between 41 and 78 years compared to those with one or no copy of the defective gene.
  • Risk reduction of HIV transmission by:
    • Consistent therapy of sexually transmitted infections (42%).
    • Condoms (85 %
    • Antiretroviral therapy (ART) (96 %)
    • ART and condoms (99, 2%).
    • Exposure prophylaxis in those not infected with HIV (86%).
  • Vaginal ring with the active ingredient dapivirine (risk reduction: 31-63%).
  • Pre-exposure prophylaxis (PrEP): see below.
  • Prophylaxis of mother-to-child transmission of HIV: antiretroviral therapy in terms of HAART (highly active antiretroviral therapy), pre-, peri- and neonatal (“before and around birth” and “concerning the newborn”) + elective sectio (cesarean section) + breastfeeding abstinence leads to a risk reduction of transmission (transmission) to below 2%.
  • Effective viral suppression by antiretroviral drugs with a decrease in viral concentration to below 200 copies/ml protects the sero-negative partner from transmission by the sero-positive partner. One study concluded the following in this regard:
    • In heterosexual couples
      • Man HIV-positive and woman HIV-negative: annually to 0.97 infections per 100 couples.
      • Woman HIV-positive and man HIV-negative: annually to 0.88 infections per 100 couples.
    • Men who have sex with men (MSM): annually 0.84 infections per 100 couples. For receptive anal intercourse with ejaculation into the rectum, the 95 percent confidence interval ranges to 2.7 infections per 100 persons per year. After ten years, the risk would accumulate to 27 percent.

Pre-exposure prophylaxis (PrEP)

PrEP (also HIV-PrEP) is the abbreviation for “pre-exposure prophylaxis”, in German: Vorsorge before a possible HIV contact.PrEP is a safer sex method in which HIV-negative people take an HIV medication to protect themselves from contracting HIV. Note: Conventional PrEP is recommended to be taken daily. For men who have sex with men, there is also occasion-based PrEP, which involves taking pills around sex (see “PrEP on demand” below). A joint guideline on HIV pre-exposure prophylaxis (PrEP) has been presented by the German and Austrian AIDS Societies (DAIG). Among other things, the S2k guideline describes oral HIV pre-exposure prophylaxis (PrEP): “the use of systemically active antiviral drugs by HIV-negative persons at increased risk for HIV infection to reduce the probability of HIV transmission.” Studies have shown a relative risk reduction of 86%, and up to 99% with high adherence. The FDA approved Truvada (combination tenofovir-DF/emtricitabine, TDF/FTC) for HIV pre-exposure prophylaxis (PrEP) in July 2012. The drug is taken for MSM (men who have sex with men). Tenofovir alafenamide/emtricitabine (Descovy) was approved by the European Commission in 2016. The drug can also be used in cases of impaired kidney function up to 30 ml/min and has less impact on bone mineral density.The WHO recommends PrEP for at-risk populations (MSM, prisoners, sex workers, transgender people, intravenous drug users) in a guideline. This population accounts for 50% of all new HIV infections worldwide. Medicines

Truvada has also been approved for PrEP in Europe since July 2016. In the meantime, other generics have been approved. For PrEP, the oral combination drug emtricitabine/tenofovir disoproxil (TDF/FTC* ) is to be used. * The generics mainly used contain other tenofovirdisoproxil salts with the same oral bioavailability as the -fumarate (-phosphate, -maleate, and -succinate). In addition to conventional PrEP, “PrEP on demand” is also recommended. Therapeutic regimen: 2-1-1 regimen (taking two tablets of tenofovir/emtricitabine 24 hours to no later than 2 hours before sexual contact and continuing for two days after sexual contact). This reduces the risk of infection by 86%. PrEP has been a health insurance benefit for high-risk patients since September 2019. New active ingredients (studies)

  • In a study of men who have sex with men (MSM), 66% fewer new infections occurred during therapy with the integrase strand transfer inhibitor cabotegravir, which requires intramuscular injection in a special formulation only every 8 weeks, compared with emtricitabine/tenofovir: The HIV incidence rate was 0.41% (0.20% to 0.66%) in the cabotegravir group versus 1.22% (0.86% to 1.66%) in the emtricitabine/tenofovir group.Side effects: Cabotegravir injections: more frequent fever and pain at the injection site than subjects in the comparison group; subjects with daily oral PrEP more frequently complained of nausea than study participants who swallowed a placebo tablet instead of emtricitabine/tenofovir.

Effectiveness of PrEP

MenThe effectiveness of conventional PrEP is high in men:

  • In the PROUD study, one man (1.3%) became infected with PrEP in one year, compared with 9 men (8.9%) without PrEP in one year.
  • In the Partner2 study: HIV-infected persons with undetectable viral load (less than 50 viral copies per ml of blood) are not infectious even with condomless sexual intercourse; this applies to heterosexual as well as homosexual sexual partners.

WomenThe effectiveness of PrEP is limited in women: it varied from 49% in the VOICE trial to 75% in the TDF2 trial when tenofovir or tenofovir-emtricitabine was used orally. With vaginal preexposure prophylaxis, the protective effect was only 0% (FACTS) to 39% (CAPRISA). Studies show that Gardnerella vaginalis is responsible for the loss of protective efficacy.In contrast, in women without signs of inflammation in the smear, the protective efficacy of the vaginal gel with the active ingredient Tenofir was 57% (95% confidence interval 7 to 80%). It increased to 75% (25% to 92%) if the women had used the gel regularly before sexual contact.Side effects: The most common side effects were diarrhea (diarrhea), nausea (nausea), abdominal pain, headache, and weight loss. Additional Notes

  • A meta-analysis showed that people who took preexposure prophylaxis (PrEP) were likely to neglect protection against other sexually transmitted diseases (STDs). The group of people had an increased risk of other STDs such as chlamydial infection, gonorrhea, or syphilis. In the first 3 months of PrEP, there was already a significant increase in new infections.
  • A joint study by the Robert Koch Institute with infectious diseases focus practices from nine major German cities provides information on, among other things, the prevalence (disease frequency) of sexually transmitted infections (STI) in patients on HIV pre-exposure prophylaxis (PrEP):
    • HIV-positive participants: 31% STI.
    • HIV-negative participants without PrEP: 25%.
    • HIV-negative participants with PrEP use: 40%.

    Sex without a condom was reported by 74 percent and party drug use by 45 percent.There was an increased risk of STI with more than five sexual partners (factor of 1.65), sex without a condom (2.11), and party drug use (1.65).

Post-exposure prophylaxis (PEP)

Post-exposure prophylaxis is the provision of medication to prevent disease in individuals who are not protected against a particular disease by vaccination but have been exposed to it. For more information, see “Drug therapy.”

Secondary Prevention

  • Coffee consumption (≥ 3 cups) halves all-cause mortality risk in patients infected with HIV-HCV.