The Biology Project: Immunology

HIV and AIDS Problem Set

Problem 2: Risk for HIV transmission

Tutorial to help answer this question

Which activity has a high risk of HIV transmission?

  1. Living with someone who is HIV+
  2. Receiving a blood transfusion today, with blood that has been screened for HIV
  3. Sexual intercourse without a condom
  4. Working as a paramedic


Blood, semen (including pre-ejaculation fluid), vaginal secretions, and breast milk of infected individuals all contain high concentrations of HIV and can transmit HIV. These fluids must have direct access to your bloodstream in order to infect you. Activities where this can happen include vaginal intercourse, anal intercourse, performing oral sex, sharing unsterilized needles for IV drug use or tattoos, and through receiving a blood transfusion where the blood has not been screened for HIV. (The US blood supply has been screened for HIV since 1985.)

HIV is NOT transmitted through any form of casual contact. HIV is NOT transmitted through shaking hands, hugging, kissing, massaging, or living in the same house with someone who is HIV+. Recall that unbroken skin is an effective barrier against antigen. HIV can only gain access to the bloodstream through an open sore or abrasion. Health care workers can care for HIV+ patients every day for years without becoming infected themselves. However, health care workers should take care to prevent direct contact with any body fluids.


The Biology Project
The University of Arizona
Monday, April 3, 2000
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