Risks of Sharing Needles: HIV and Syphilis Concerns

Shared needles

Hello doctor, I recently shared a needle for intravenous injection with an HIV patient.
What is the likelihood of infection? I used the needle at least an hour after he did.
I've seen various claims online about the virus survival time, ranging from 3 minutes to several hours; which one is correct? Additionally, how long after contracting syphilis will a rash appear on the arm? If infected with HIV, will there also be a rash on the arm, or is it only on the front of the body? Will the appearance of the rash be similar to that of syphilis?

Xiao Kai, 20~29 year old female. Ask Date: 2022/12/21

Dr. Hong Yuanbin reply Internal Medicine

Hello, sharing needles can lead to infection regardless of how long they have been used.
Therefore, it is crucial not to use needles that have been used by others.
The so-called rash is associated with secondary syphilis, which typically occurs approximately six weeks to six months after infection.
HIV infection may present symptoms similar to those of a cold, and a rash is not always present.
It is recommended that if you have shared needles and are feeling unwell, you should get tested for HIV as soon as possible.
Thank you for your question.

Reply Date: 2022/12/21

More Info

When it comes to understanding the risks associated with sharing needles, particularly in the context of HIV and syphilis, it is crucial to recognize the transmission dynamics of these infections and the factors that influence the likelihood of infection.

Firstly, sharing needles with someone who is HIV positive poses a significant risk of transmission. HIV is primarily transmitted through blood, and sharing needles can introduce the virus directly into your bloodstream. The risk of infection is particularly high if the needle has been used recently, as HIV can survive in a used needle for varying periods depending on environmental conditions. While some sources suggest that HIV can survive outside the body for only a few minutes, others indicate that it can remain viable for several hours in a needle. The consensus is that the risk of transmission increases the sooner you use the needle after someone else has used it. Therefore, waiting an hour does not eliminate the risk, as the virus may still be present in the needle.

Regarding syphilis, it is important to note that it is primarily transmitted through direct contact with syphilis sores during sexual activity, rather than through blood. However, if a person has syphilis and there are open sores or lesions, there is a potential risk of transmission through blood if shared needles are involved. The appearance of a rash or lesions associated with syphilis can vary, but typically, secondary syphilis may present with a rash that can appear anywhere on the body, including the arms. This rash usually develops several weeks to months after the initial infection if left untreated.

If you were to contract HIV, the symptoms can vary widely. Some individuals may experience acute retroviral syndrome (ARS) within 2 to 6 weeks after infection, which can include flu-like symptoms such as fever, fatigue, and rash. The rash associated with HIV is not limited to the arms or any specific area; it can occur anywhere on the body and may not resemble the rash seen in syphilis.
In summary, the risk of HIV transmission through shared needles is significant, and the timing of needle use does not guarantee safety. If you have shared needles, it is highly advisable to get tested for both HIV and syphilis as soon as possible. Testing is the only way to confirm your status and to seek appropriate medical care if needed.
If you notice any unusual symptoms, such as rashes, sores, or flu-like symptoms, it is essential to consult a healthcare provider promptly. They can provide guidance on testing and treatment options, as well as support for any concerns you may have regarding your health. Remember, practicing safe injection practices and avoiding sharing needles is crucial in preventing the transmission of HIV and other bloodborne infections.

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