Can HIV Be Spread Through Casual Contact?

Understanding Why Touching, Kissing, Sneezing and Hugging Cannot Transmit HIV

Photo Credit: James Gathany/CDC Public Health Image library ID 11162

Question: Can HIV be transmitted through casual contact with an infected person?

Answer: The simple answer would be "no," but it is clear that doubts do still persist in many people's minds, whether spoken or unspoken. Dismissing those doubts does little to diminish the fears and anxieties associated with HIV infection or to reinforce a clear understanding of how HIV is actually transmitted.

It is, perhaps, better to explain what it takes to transmit the virus from one person to the next, as well as the limitations that effectively prevent HIV from causing infection though hugging, touching, sneezing or kissing.

Layperson's Guide to HIV Transmission

There are four conditions that must be satisfied in order for an HIV infection to occur. Take away any one of these four condition and the ability of HIV to infect drops away. It's as simple as that.

  1. There must be body fluids in which HIV can thrive, such as semen, blood, vaginal fluid or breast milk. HIV cannot thrive in the open air or in parts of the body where is high acid content such as the stomach or bladder.
  2. There must be a way for these body fluids to enter the body, either through certain sexual activities, shared needles, healthcare exposure, or transmission from mother to child during pregnancy.
  3. There must be a means for the virus to reach vulnerable cells in your body, either through a rupture or penetration of the skin, absorption through mucosal tissues of the vagina or rectum. HIV cannot penetrate intact skin, and the likelihood of infection is directly related to the depth and size of the penetration. Scrapes and abrasions are less likely to provide a route entry, for example, that an a deep, open cut or wound.
  1. There must be sufficient amounts of virus in the body fluid, which is why saliva, sweat and tears are unlikely sources since the amount of virus in these fluids is considered insufficient for infection. Within these types of body fluids are enzymes and proteins (such as lysozyme and ribonuclease) that actively break apart the genetic material of HIV, as well as the core structure of the virus itself.

    Many people have this misconception that HIV is a sturdy virus.When compared to other types of viruses—such as the adenovirus which is associated with the common cold—it is clearly not. The exterior lipid structure of HIV is actually quite flimsy, which is why it cannot be aerosolized and spread by sneezing. It is also why HIV cannot live outside of the body for very long and certainly not in quantities sufficient for infection.

    Ways in Which HIV Cannot Be Spread

    From both a biological and evidence-based point of view, HIV cannot and has never been shown to be passed from one person to the next by the following means:

    • Touching, hugging, kissing or shaking hands with an HIV-positive person
    • Touching an object an HIV-infected person has touched
    • Sharing utensils or drinking cups with an HIV-positive person
    • Eating food, cooked or uncooked, that an HIV-positive person has prepared
    • Sharing grooming items, even toothbrushes or shaving paraphernalia
    • Getting spit upon, even in the eyes or mouth, or coming 
    • Getting bitten by an HIV-positive person, even if blood is drawn
    • Touching semen or vaginal fluids, or getting it on your skin
    • Touching blood from an HIV person, or getting it on your skin
    • From drinking fountains, toilet seats or public showers
    • From pet, animal or insect bites

    To date, there has not been a single documented case of transmission by any of these means. Even those rare incidences reported in the early part of the AIDS epidemic (in which HIV was believed to have been transmitted through shared razors, toothbrushes and even moisturizing cream) are considered dubious at best, limited by the both our understanding about the disease at the time and the lack of evaluative testing technologies.  

    Are There Exceptions to the Rule?

    Most health professionals will have, at one time or another, met with patients who have variations of the above-listed events yet still strongly believe that HIV transmission is possible.

    Perhaps the person was involved in a fight or happened upon an injured, bleeding person. Others might worry about having french kissed a person known to have HIV or had accidentally gotten semen in their eyes during sex.

    While it might seem clear that the likelihood of infection is negligible to nil, people often want a 100% guarantee that they've not been infected, and nothing short of this will ease their fears. In such cases, it's important to evaluate the event to relationship to the above-listed conditions, and for the patient and doctor to do together. In this way, the patient has a better understanding of not only HIV transmission but ways to prevent getting HIV in future.

    It also provides the means to explore HIV testing, which is today recommended for all Americans ages 15-65 as part of routine doctor's visit.

    If the patient is still convinced that an infection may have occurred (and the exposure took place within the past 72 hours), HIV post-exposure prophylaxis (PEP) can be prescribed, if appropriate. If  this is done, however, it is important that the patient be counseled stringently about future harm reduction.

    If the patient has extreme or unreasonable anxiety (often referred to as AIDS phobia), it is important that the person be referred a specialist counselor or psychologist trained in HIV. 


    U.S. Preventive Services Task Force (USPSTF). "Screening for HIV: U.S. Preventive Services Task Force Recommendation Statement." Rockville, Maryland; April 2013; accessed February 7, 2014.

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