Postexposure Prophylaxis

Basics

Hiv

  • Antiviral medication to prevent HIV in a patient who may have been recently exposed
  • Exposure typically occurs through sexual intercourse or sharing needles
  • Exposures for which postexposure prophylaxis (PEP) should be considered:
    • Vaginal or anal intercourse
    • Oral sex with ejaculation or blood exposure
    • Injuries with exposure to blood from a source with known HIV or unknown status (including needlesticks and human bites)
  • Not recommended for people who were exposed to non–blood-contaminated secretions, as their risk is very low:
    • Exposure to urine, saliva, sweat, tears, or nasal secretions
    • Kissing, spitting, oral-to-oral contact in the absence of mucosal damage (eg, mouth-to-mouth resuscitation)
    • Human bites not involving blood

Anthrax

  • Natural infection or bioterrorism weapon

Pertussis

  • Acute respiratory tract infection
  • Bronchiolar congestion, obstruction, necrosis
  • Hypoxia, CNS involvement

Rabies

  • Highest fatality of any infectious disease (ID)

Epidemiology

Hiv

  • Risk of HIV transmission in health care setting if source is HIV positive:
    • Needlestick: 0.3%
    • Mucous membrane exposure: 0.09%
  • Risk of HIV transmission in nonhealth care setting:
    • Needle sharing: 0.63%
    • Anal Intercourse: 0.5–3%
    • Vaginal intercourse: 0.08–0.3%
  • Factors that increase risk of transmission:
    • Source with high HIV viral load
    • Activity involving exposure to blood
    • Hollow-bore needle injury/presence of blood on needle
    • Absence of barrier protection
  • Risk of Hepatitis B virus (HBV) from needlestick:
    • 22–31% if source HBeAG+
    • 1–6% if source HBeAG−
  • Risk of Hepatitis C virus (HCV) from needlestick is 1.8%

Anthrax

  • Bacillus anthracis (gram-positive rod)
  • Zoonotic disease
  • Inhalational, cutaneous, GI exposure
  • Incubation <1 wk for cutaneous/GI
  • Incubation for inhalation: 2–43 d

Pertussis

  • Bordetella pertussis
  • Spread by small droplets
  • Incubation 6–20 d (usually 7–10 d)

Rabies

  • 2–3 cases in US per year
  • Bats most common reservoir followed by skunks, raccoons
  • Small rodents usually not carriers(squirrels, rats, hamster)

Varicella

  • Incubation: 14–16 d
  • Adults 15 times greater risk of death than children

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