Bloodborne HIV: Don't Get Stuck!

Protect yourself from bloodborne HIV during healthcare and cosmetic services

Estimated risks to get HIV from reused skin-piercing instruments

Good evidence of the risk to get HIV from skin-piercing procedures comes from studies of healthcare workers getting HIV after needlestick accidents (sticking or cutting themselves with instruments just used on someone with HIV) and from investigations of HIV outbreaks when skin-piercing health care infected hundreds of patients.

Here’s evidence from needlestick accidents

A summary of 23 studies reported 3 in 1,000 (0.3%) healthcare workers exposed to HIV through needlesticks got HIV.[1] From such data, many people – including health experts who should know better – say the risk to get HIV after an injection with a contaminated syringe or needle is 0.3%. A closer look at needlestick accidents shows a much greater risk to transmit HIV through accidents that are similar to injections and other skin-piercing medical procedures.

Specifically: a 1997 study of healthcare workers who did and did not get HIV after needlestick accidents found that most accidents were shallow scratches.[2] Only 7%  were deep injuries, deep enough for the hole of the needle to be within the skin, as in an injection. The risk to get HIV after deep needlesticks was 15 times greater than for all needlesticks.

Thus, from needlestick accidents, a first approximation of the risk to transmit HIV through injections – all of which fit the definition of a deep injury – is 4.5% (or 15 times the 0.3% average risk for all needlesticks). The same study found other factors could raise or lower that risk – for example, risks could be even greater if the source patient was very sick with a lot of virus, or if there was blood visible on the instrument.

Here’s evidence from investigated outbreaks

Investigations of HIV outbreaks from unsafe health care provide other evidence about patients’ risks to get HIV from skin-piercing instruments. In Elista, Russia, in 1988-89, for example, hospitals spread HIV from 1 to more than 260 children within 15 months (see For HIV to go from 1 to 260 children in 15 months, the number of infections had to double 6 times — doubling on average every 2.5 months. To get to 260 infections in 15 months, each HIV-infected child had to, on average, infect another every 2.5 months. If the risk to transmit HIV through contaminated equipment was 0.3%, an HIV-positive patient would have to have, on average, more than 300 skin-piercing procedures (1 = 333 x 0.3%) after which equipment was reused without sterilization for HIV to go from him or her to another patient. That would take years, not just several months. Similarly, in Roka Cambodia, HIV went from 1 to 198 patients in an estimated 15 months (see figure 2b in Rouet et al[3]; see also

Clearly, in these investigated outbreaks the risk to transmit HIV through reused and unsterilized instruments was much greater than 0.3%. If an HIV-positive person in Russia got an average of 10-50 skin-piercing procedures before HIV reached and infected someone else, then the risk to transmit would be 2% (1 = 50 x 2%) to 10% (1 = 10 x 10%). These are crude estimates – but certainly more realistic that the widely reported 0.3%.

The estimates in the following table for the risk to get HIV from contaminated instruments are based on information from needlestick accidents and outbreaks.[4,5] The estimates in this table are by no means solid numbers, but they are much better than the widely quoted and believed 0.3%. And risks will vary according to many other factors, such as how much HIV in the source patient’s blood. So these are approximations only.

Table: Risk to get HIV from HIV-contaminated skin-piercing instruments
Skin-piercing procedures with unsterilized instruments Estimated risk
Medical procedures
Transfusion with HIV-positive blood ~100%
intramuscular or subcutaneous 0.5% to 3%
Intravenous 3% to 10%
Blood tests
collecting blood from a vein 3% to 10%
collecting blood drops from a finger or toe <1%
Infusions, surgery, other medical procedures At times >10%
Pulling or filling teeth At times >10%
Cosmetic procedures
Tattooing At times >10%
Piercing <1%
Manicures and pedicures <1% to 3%?
Shaving, haircutting (when cuts occur) <1%
Hair straightening, styling (with scalp sores) ?

How long does HIV survive on skin-piercing instruments?

If you are worried about getting HIV from bloodborne risks, it’s important to know that HIV survives for a long time wet or dry, in or on contaminated skin-piercing equipment. This is an issue that has been carefully studied in laboratory experiments. For example, a study found viable HIV (able to infect) after six weeks in syringes stored at room temperature; the study used blood with concentrations of HIV typical in untreated adults.[6] And a study of HIV survival after drying found that it took 9 hours for the numbers of viable HIV (able to infect) to fall by 90% — in other words, after 9 hours, 10% of the HIV initially on the surface was still able to infect.[7]

Many experts cite the US Centers for Disease Control and Prevention (CDC) to say “HIV does not survive long outside the human body…”[8] What does that mean? Here’s more of what CDC says about HIV survival outside the body. “Studies performed at CDC have also shown that drying HIV causes a rapid (within several hours) 1-2 log (90%-99%) reduction in HIV concentration.”[9] For anyone wondering about whether a reused razor, scalpel, manicure tool might transmit HIV, maybe 90% will die in several hours. Waiting for all HIV to die (inactivate) might take days. And how would one know how long a used razor or scalpel has been lying around? To be safe, don’t ask how many hours ago reused instruments were used on someone else. Ask instead if they have been sterilized (or at least boiled).

Similarly, CDC reports “In tissue-culture fluid, cell-free HIV could be detected up to 15 days at room temperature…”[9] So if you are getting an injection, infusion, or another procedure with instruments that might contain wet blood, you would need to wait many weeks to be sure all HIV from a previous patient had died (was inactive, not able to infect). Much better to simply ask if the instruments have been sterilized.

Also, remember that HIV is not the only risk. Whatever you do to avoid unsterile skin-piercing instruments will protect you not only from HIV but also from other bloodborne infections, such as hepatitis B and hepatitis C.


1. Bell DM. Occupational risk of human immunodeficiency virus infection in healthcare workers: an overview. Am J Med 1997; 102 (Suppl 5B): 9-15. Abstract available at: (accessed 20 February 2021)

2. Cardo DM, Culver DH, Ciesielski CA, et al. A case-control study of HIV seroconversion in health care workers after percutaneous exposure. N Eng J Med 1997; 337: 1485-1490. Available at: (accessed 22 February 2021).

3. Rouet F, Nouhin J, Zheng D-P, et al. Massive iatrogenic outbreak of human immunodeficiency virus type 1 in rural Cambodia, 2014-2015. Clin Infect Dis 2018; 66: 1733-1741. Available at: (accessed 24 February 2021).

4. Gisselquist D, Upham G, Potterat JJ. Transmission efficiency of HIV through injections and other medical procedures: evidence, estimates, and unfinished business. Infect Control Hosp Epidemiol 2006: 27: 944-952. Abstract available at: (accessed 22 February 2021).

5. Gisselquist D. HIV transmission efficiency through contaminated injections in Roka, Cambodia. Biorxiv 2017. Available at: (accessed 4 March 2018).

6. Resnick L, Veren K, Salahuddin SZ, et al. Stability and inactivation of HTLV-III/LAV under clinical and laboratory experiments. JAMA 1986; 255: 1887-1891. Abstract available at: (accessed 21 Feb 2021).

7. Heimer R, Abdala N. Viability of HIV-1 in syringes: implications for interventions among injection drug users. AIDS Reader 2000; 10: 410-417. Abstract available at: (accessed 21 Feb 2021).

8. Ways HIV in not transmitted. CDC [internet] Oct 2020. Available at: (accessed 21 Feb 2021).

9. Centers for Disease Control. Recommendations for prevention of HIV transmission in health-care settings. MMWR 1987; 36 (suppl 2S). Available at: (accessed 7 January 2011).

91 responses to “Estimated risks to get HIV from reused skin-piercing instruments

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  4. Simon Collery November 10, 2011 at 12:41 pm

    Thank you Liz, that very much depends on where you are and what medical facilities are like there. If you’re in a Western country, or a Western style health facility anywhere, it’s unlikely that you face any risk. If you’re in a developing country, especially where health services are generally poor and blood borne diseases are common, then you need to look through the various sections on this site relating to Patient Observed Sterile Treatment. But do get in touch if you can’t find what you want.

  5. Simon Collery November 11, 2011 at 6:03 am

    Hi Liz, Nairobi has some good hospitals but even Western hospitals have lapses and hepatitis, HIV and other blood-borne viruses can be transmitted. There have also been a lot of possible outbreak investigation where tens of thousands have been recalled just to be sure. So it sounds like there is a serious question mark over how you became infected. The sexual risk involved is very low, whereas a lapse in a hospital can be a high risk. Nairobi has the second highest prevalence in the country. I’d be surprised if anyone there is highly skilled in outbreak investigations and it would be better to find a specialist who can help you establish as much as possible about the circumstances of your infection. It’s possible that your infection is not just a once off, that others have also been exposed and should check their status for a number of diseases before more damage is done. I’ll inquire further and get back to you.

  6. vince jones March 15, 2012 at 7:44 am

    You’re full of shit,Hiv becomes inactive and therefore unable to infect you as soon as it is exposed to air

  7. vince jones March 15, 2012 at 7:48 am

    again you are full of shit and don’t know what you are talking about because HIV is not dead or alive,it’s either active or inactive,it’s information like yours that makes people panic for no reason,this website should be banned.

    • davidgisselquist March 15, 2012 at 3:39 pm

      Hi Vince,
      Thanks for your comment. A lot of misinformation has circulated on this topic.
      Over the years, many scientists have kept HIV outside the body for hours to weeks in wet or dry conditions and then checked to see if it could infect cells. All reports from these studies say that HIV survives hours to days in dry conditions and for weeks if wet.
      For example, a 1986 article in Journal of the American Medical Association reports that: “Dried and held at room temperature, HTLV-III/LAV [names for HIV in 1986] retains infectivity for more than three days with a reduction of approximately 1 log10TCID50 [ie, reduction of 90%] per nine hours.”
      A 1985 article in Lancet by Barre-Sinoussi (who received a Nobel prize for discovering HIV) and others reports that for virus kept wet at room temperature, “No significant difference [in infectivity] was found between 0, 2, and 4 days” and “Only a slight decrease…after 7 days…” For virus dried and kept at room temperature, “some infectious virus is still present…” after 4 and even 7 days. “This result indicates that the virus [HIV] is resistant at room temperature, either in dry form or in liquid form.” The authors recommend: “…some more safety precautions should be taken in laboratories and in hospitals and by dentists…”
      A 2006 review of these and similar studies (which is availabe in full on-line) reports that on dry surfaces: “Blood-borne viruses, such as HBV [hepatitis B virus] or HIV, can persist for more than one week.”

  8. Anonymous November 22, 2012 at 12:10 pm

    If HIV wasn’t killed easily in dry surfaces , the whole planet would be infected.

  9. Matt March 31, 2013 at 3:41 pm

    You are a paranoi provoking scare monger telling people hiv dies after months outside the body, this is completely untrue! It dies within 5 minutes and if a doctor says it its good enough for me! People often look to the internet for reassurance and you should be ashamed of yourself for inciting such idiology! People like you are the true virus

  10. Simon Collery April 1, 2013 at 10:47 am

    Matt, thank you for your comment. I don’t think anyone claimed that HIV survives for months. However, one often hears the claim that ‘HIV dies in seconds’, which it does not. Some also believe that it necessarily dies in minutes, which is also untrue. If you disagree with any of the references cited above it would be better to contact the authors, rather those who run this site, who are merely bringing the evidence together so people can judge better for themselves.

  11. graham April 2, 2013 at 5:15 am

    Please stop scare mongering with poorly interpreted information. The CDC clearly states that HIV kept alive outside the body has been done so in very specific laboratory conditions with artificially grown HIV in much larger quantities than found in a HIV+ person’s blood. Infectious reduces between 90-99% within a few hours even in these large quantities. I quote “Theoretical risk of environmental transmission to that which has been observed–essentially zero. Incorrect interpretations of conclusions drawn from laboratory studies have in some instances caused unnecessary alarm.”
    I recommend you contact the CDC yourself and see if they agree with what you’re saying on this website.

    • Jennifer January 15, 2016 at 8:07 pm

      Monogamy, no needle use, still I have to just accept it? no, there is too much with healed from the public

  12. Simon Collery April 2, 2013 at 7:00 am

    Graham, thank you for your message. As we disagree with the conclusions of CDC, UNAIDS, WHO and others on the matter of non-sexual HIV risks, it would be somewhat circular to ask them to verify what we have made available on this site. However, we are warning about risks that even those august institutions would agree exist; we just disagree about how likely they are to contribute substantially to an epidemic. The risks we are talking about are not casual events that may go unnoticed. We are talking about injections, visits to the dentist, tattoos and various other skin-piercing procedures that are well known as risks for HIV and other bloodborne diseases. The risks we are talking about do not generally relate to HIV ‘staying alive’ for any significant length of time. That’s why there have been outbreaks of non-sexually transmitted HIV in many Western countries, which have given rise to tens of thousands of people being recalled, even many years after receiving treatment where use of contaminated instruments is suspected. The issue we wish to draw attention to is that there have been no investigations, recalls and mass testings as a result of such possible outbreaks in countries with the worst epidemics in the world.

  13. davidgisselquist April 4, 2013 at 11:30 pm

    Hi Graham. Thanks for your interest in the site.
    The sentence you quote from CDC refers to “environmental transmission,” such as getting infected by touching a table-top that has HIV. CDC says that there has been “essentially” no such transmission from dried HIV. That is not what we are talking about in this site; “environmental” transmission does not include sharing skin-piercing instruments in health care and cosmetic services. CDC staff know as well as we do that there have been huge outbreaks of HIV — HIV spreading from one person to hundreds and even thousands in a few years — through skin-piercing medical procedures in China, Romania, Libya, and elsewhere.
    In the link you give, CDC staff say that even after HIV has dried (how long does that take?) 1%-10% of whatever was there initially will be infectious for several hours. The laboratory experiments that CDC staff refer to in that statement have never been described in a refereed medical journal — so we do not know the details. CDC’s estimates of HIV survival in dry conditions are a bit on the low side compared to what has been reported in laboratory experiments reported in refereed medical journals, but even so, we are talking about hours after drying, not minutes outside the body.
    Here’s the gist: If you want to be sure there is no infectious HIV on a skin-piercing instrument that has not been sterilized after touching someone else’s blood, you should wait for days to a week or more after the blood has dried. If the instrument remains wet (eg, some moisture inside a syringe) you should wait for a month or ore. But even then, you would have to worry about hepatitis B. So avoid reused, unsterilized instruments.

  14. Nicole October 19, 2013 at 6:46 am

    My question is if someone dies, has been dead for over a day is the virus still alive inside the body? If you were to get their infected blood in ur eye while doing an autopsy or something could you still get infected?

    • davidgisselquist October 24, 2013 at 2:14 am

      HI Nicole. Thanks for your question. Sorry for taking time to reply.
      Getting blood from a dead body into a cut might transmit HIV, even if the person has been dead for a week (see link and quote below). Getting a blood splash into an eye, whether from someone living or dead, seems to be very low risk. It’s hard to find reports of anyone infected that way.
      Quote from Infectious HIV has been recovered from human corpses between eleven and 16 days after death in bodies stored at the usual mortuary temperature of 2°C. It is unclear how long infectious HIV may persist in corpses left to decay at normal room temperature, but HIV has been cultured from organs stored at 20°C up to 14 days after death. HIV was not detected in significant quantities later than 16 days, implying that buried corpses or those preserved for long periods pose less of a risk to undertakers and pathologists.

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  16. Dan April 24, 2014 at 10:56 pm

    Hello, I have been reading your articles on this subject and I am wondering whether you are talking about HIV surviving outside the body for some time, in a laboratory under certain conditions or in the environment such as outside or inside. This would be a great help for me just so I can take extra precautions.

    Many Thanks.

  17. Simon Collery April 25, 2014 at 8:46 am

    Thanks Dan, the question has been asked several times on this site and answered each time, some of the answers appearing on this very page. However, I would urge you to ask some other questions rather than getting wrapped up in whether the virus does or does not ‘die in seconds/minutes/hours’ on ‘dry/cold’ surfaces, inside syringes or needles, or whatever kind of device:

    1 Would you allow someone to use an unsterilized and non-reusable device on you (or your partner or children), even one that had been unused for several days/weeks/months?
    2 Would you allow someone to use the device if they had washed it in bleach, surgical spirit or other antiseptic?
    3 Would you risk allowing someone else’s blood or other bodily fluids to come into contact with your blood or other bodily fluids, in your body, through any healthcare, cosmetic or other procedure?
    4 Would you feel confident about receiving an injection or other procedure in a place that looked as if it was not able to guarantee that everything is sterile?
    5 Would you give blood if you knew that the non-reusable equipment was being reused, even if it had been washed or sterilized?
    6 Would you have a tattoo in a place where the artist tried to reassure by saying that ‘HIV dies in seconds outside the body’ or some such platitude?

    I think questions like that are far more important than how long a virus survives in or out of the body, under what conditions, etc. They are just a few examples. Another thing you could do is check out the ‘Cases and Investigations’ tab above and read about what can happen when non-reusable devices are reused, etc.

    For those who have been infected, the most important thing is that the treatment they received was unsafe when it should have been safe; they are not asking how long HIV survives, but questions such as why they were infected and whether the same health facilities are now aware of the problem and making sure that such healthcare associated infections are no longer occurring.

    If you are interested in taking precautions you could check out the various pages under the ‘Healthcare Risks’ and ‘Cosmetic Risks’ tabs, above on this site.

  18. Louvenia October 5, 2014 at 2:58 pm

    A motivating discussion is definitely worth comment.
    I believe that you should publish more on this issue, it might not be a taboo subject but generally people don’t talk about these issues.
    To the next! Best wishes!!

  19. Nina November 29, 2014 at 7:52 pm

    It happened to my brother. He contracted it after receiving a tattoo after his step brother with the same needle. The needle was wiped and the blood was dry. You know it had to take over a minute for him to prepare to for my brothers tattoo. So it does happen. People aren’t taking precautions bc they believe it won’t happen.

    • Simon Collery November 30, 2014 at 8:25 am

      Thanks for your comment Nina, I’m sorry to hear what happened to your brother. We really need practitioners and patients to be aware of the risks to prevent such things from happening and so people can protect themselves. Whether a virus survives for a minute or a year, equipment and practices should always be sterile; no one should be exposed to the blood or bodily fluids of another person, whether it’s as a result of cosmetic, traditional or medical practices.

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  21. Pm January 10, 2015 at 5:01 pm

    Hi, I have an urgent question which is tearing me apart. I have been living in Singapore for the past year and happened to pass through a run down mall with some of the worst loos I have seen in singapore. I saw a small beauty salon and decided to get my eyebrows and upper lip threading (to get rid of hair) there since I was hard pressed for time and expected visitors next morning. I kind of knew that the clientele of such a place would be Chinese immigrants who have entered singapore to work at domestic maids or labourers but still I expected hygiene standards to be followed as they usually are in singapore. The person who was to work on me didn’t know any English, she opened the door of a tiny room where I could see a woman lying in the dark, she wheeled out a trolley from that room which had her instruments and began using them on me. For some reason which I will never understand, I didn’t object to anything – she used a crumpled tissue to wipe my eyebrows, used a thread to pluck out my hair, then scissors, then a tweezer with someone else’s hair sticking to it. I was disgusted but was focusing my attention on my 16 month old baby who was sitting in his stroller and trying to touch things which I wanted to prevent. Then I noticed that she was using a razor on my eyebrow, I have never heard of it being used on an eyebrow and was shocked. It was not disposable, she hadn’t changed the blade and after I said no, she put it back in the same stand which had 4-5 identical razors, even though she had used it on 1 of my eyebrows. I kicked up a fuss so her colleague came and told me that they change the razors everyday, I don’t know whether to believe that or not. At home I saw a tiny nick on that same eyebrow – don’t know if the razor or threading caused it. A tiny strip of blood could be seen and it was burning slightly. But it wasn’t big enough to notice if I hadn’t been looking for it. I haven’t been able to sleep or stop crying since this episode because until this incident I have been breast feeding my son (through pumped milk) since he is extremely allergic to cows milk. He has alimentum formula which is extensively hydrolysed but one third of his daily requirement was being met by my breast milk. it gave me deep satisfaction and a sense of purpose to know that I was giving him my milk with all it’s goodness of antibodies etc and wanted to continue till he was 2 years old. Desperately need your opinion on whether I should stop breast feeding or take the risk of passing on HIV to him in case I get it and continue feeding him. Please help!

  22. Simon Collery January 10, 2015 at 5:32 pm

    Hi Misra, thank you for your email, I’m sorry to hear about the experience you have had. The first thing you should do is go to a physician as soon as possible to get the best advice for you and your child. We are not physicians but the sooner you go to see one the better. The experience you had sounds frightening, though not particularly high risk, but please do see a professional as soon as possible!

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  24. Pm January 18, 2015 at 3:15 am

    Thanks for your reply Simon! Just one more question – how long after exposure can one reliably test for HIV? Different sources throw up different answers. Some say 4 weeks, some 3 months and some others say you can’t rule it out for 6 or more months. Wanted your take on this since I’m not sure which source to trust. Thanks a lot in advance!

    • Simon Collery January 18, 2015 at 3:37 am

      Hi, the first thing you should do if you think you have been exposed is go to a doctor, immediately. If you go within 72 hours the doctor should be able to give you ‘post exposure prophylaxis’ (PEP), which is a short course of antiretroviral drugs; this treatment has been very successful. The doctor will advise you when to test and may recommend several tests. There are different kinds and it would be best to ask an expert, even several if you think this is necessary.

  25. Neil April 2, 2015 at 9:00 am

    My roommate was bleeding all over my door during a drunken night and there was semi dried blood on my doorknob to my room. during that night while i was tired i may have rubbed my eye. what are the risks of infection through skin and in the eye.

    • Mark August 23, 2015 at 6:19 am

      Hi, I hope you can answer my question, what If an HIV patient accidentally touched his bleeding wound, then, he wiped his hand with cotton but didn’t wash. And he touched someone’s wound, is there a posibility of transmission? Though, his hand doesn’t have any visible blood. Thank you for your response.

  26. Simon Collery April 3, 2015 at 7:39 am

    Hi Neil, your risk of infection is zero if your roommate was HIV negative, and close to zero if your roommate was HIV positive. The risk from casual contact is very small indeed and, from what you describe, you only had a possible casual contact. There is no risk of infection through unbroken skin and the risk of infection through rubbing your eye is minute..Sharing injecting equipment, tattooing equipment, things that are designed to pierce the skin, can carry a high risk IF they have been used by someone who is HIV positive, but not otherwise. There are also risks from other bloodborne diseases, such as hepatitis. But it seems highly unlikely you are at risk of contracting anything at all from your recent experience!

  27. Mark August 23, 2015 at 8:23 am

    Hi, I hope you can answer my question, what If an HIV patient accidentally touched his bleeding wound, then, he wiped his hand with cotton but didn’t wash. And he touched someone’s wound, is there a posibility of transmission? Though, his hand doesn’t have any visible blood. Thank you for your response.

  28. Simon Collery August 23, 2015 at 10:30 am

    Hi Mark, thank you for your question. I would not be able to work out a definite risk, the scenario you describe sounds like a very low risk. However, it is better to avoid coming into contact with the blood of other people, regardless of their status; there are other bloodborne diseases aside from HIV. Hepatitis, for example, may be more easily transmitted than HIV. But medical practitioners (hopefully) wash their hands after coming into contact with the blood of a patient before examining another patient. Washing carefully is good advice for anyone, not just medical practitioners.

  29. Mark August 23, 2015 at 12:38 pm

    Thank you for the reply, yow about If an Hiv patient accidentally touched his bloody wound with his finger, and he wiped with dry cotton but didn’t wash,and then, he touched the cotton bud( no visible blood in both finger and cotton buds). and Then, the cotton buds was used to other Person’s wound immediately with in 1-2 minutes, is there a possible transmission?God bless you.

  30. Simon Collery August 23, 2015 at 12:52 pm

    There may be a theoretical risk, however this all seems like an unlikely scenario. It’s best not to engage in unhygienic practices, regardless of people’s HIV status.

  31. Jake September 20, 2015 at 7:58 pm

    Hi there. I have found your web page very informative. A question I would like to ask is whether blood, wet or dry on a surface, that is HIV+ contacting a mucous membrane could cause infection? For example, HIV+ blood on toilet seat and inner foreskin, urethra or frenulum of penis contacting the blood.

    Reading literature on how HIV causes infection through sexual exposure highlights that Langerhans Cells are present at the epidermis (outer most layer) of mucous membranes and can non-productively transport HIV to there target T cells. This mechanism states that HIV can bypass the mucous membrane without cut or tears at the surface. Your advise on this question would be greatly appreciated.

  32. Simon Collery September 22, 2015 at 9:18 am

    Thank you for your questions, I think the usual answer to the first one would be no, these are not risks.

    Regarding the second question, the ‘mechanism’ to which you refer sounds somewhat speculative. I’m afraid I would not be able to give an answer to it.

  33. davidgisselquist September 25, 2015 at 4:35 pm

    Hi Jake, Simon,
    Interesting questions.
    1. Regarding the first question — what is the risk to get HIV through mucous tissue coming into contact with HIV-contaminated blood? — there is some evidence from documented exposures by healthcare workers. A 1997 overview of 6 studies of healthcare workers (Bell, Am J Med, vol 102, pp 9ff) reported 1 healthcare worker getting HIV from mucous-membrane exposure (hands, eyes, mouth splashed with “a large amount of blood” while “manipulating an arterial catheter’). From this one transmission, the estimated risk is 0.09% (or about 1 in 1,000). But the risk is likely less with less blood, dried blood, etc. In any case, all blood spills can be cleaned up with chlorine, and bloody cotton should be thrown.
    2. As for the mechanism of transmission through mucous membranes: thanks for the reference. As that study says, the mechanism is unknown (as of 2008, and as far as I know remains a matter of speculation). The study is, however, misleading in an important respect — it assumes that most transmission has been through mucous membranes, which is unlikely and unproven. What we know from lots of studies following discordant couples (and from studies following healthcare workers) is that transmission through mucous membranes is so inefficient it can’t explain Africa’s HIV epidemics.
    Also a disclaimer: The dontgetstuck website does not represent biomedical experts. We follow data on who gets infected from what exposures, and we advise how to avoid infection. To do so, we don’t have to deal with or know what happens at the cellular level or below.

  34. Kay November 27, 2015 at 7:00 am

    Please help. I was collecting blood sample from an HIV patient and after removing the needle from is vein, a drop of his blood drop on my pain and I washed immediately. Is there any risk of contacting the virus?

    • Simon Collery December 7, 2015 at 10:31 am

      Hi Kay, sorry for taking a long time to reply, however, if you work for a health center, are there not ways of getting professional advice there. The risk sounds extremely low, but I think such incidents need to be reported to your employer, for the purposes of infection control. You should find out what your workplace policy is.

      • Frank January 6, 2016 at 3:21 am

        Hi Simon, I recently got poked with a needle and I believe there was hiv positive blood in the needle which was injected in me, am I going to be positive for hiv?

  35. Simon Collery January 6, 2016 at 6:06 am

    Hi Frank, you should get medical advice and ask about post-exposure prophylaxis immediately. A doctor or trained adviser should be able to explain the risk, which is probably low; but there is some risk, so don’t rely on websites! There are some estimates here on our site, but the kind of needlestick accident you describe may be lower risk than most of the types of exposure we list:

    • Frank January 6, 2016 at 6:35 am

      This needlestick happened a while back in November, I read that the window for period for prophylaxis is 3 days after the incident, the needlestick was Also on my shoulder. What do you feel I should do at this point? Thanks Simon

  36. Simon Collery January 6, 2016 at 7:42 am

    You’re right, but the advice is still the same, see a trained health professional who knows about HIV, get tested as advised, but I wouldn’t worry too much! Don’t delay any longer though!

  37. Nevermins February 8, 2016 at 6:12 pm

    What would you say for sharing nail clipper between HIV positive and negative? I did not notice any blood. Time difference is 24 hours.

    I have found one study from 2000s. In their lab they used 10,000,000 copies per mililiter and virus died within 1 to 3 days. Also, we know virus is weaker today than decades ago.

    I did not mention any blood. In the worst scenario, I had a touch with not-to-eye visible blood, so it cloud not be a 1 mililiter maybe microliter which is 1000 microliters in 1 mililiter. If we guess VL of that person is 1 million per mililiter (which is really high) it would not be too much copies per microliter. 1,000,000 / 1,000 = 1,000. But thats if we suppose that person is positive and there was some blood. I think virus in this micro blood would die. What do you think?

    • Simon Collery February 9, 2016 at 5:50 am

      As you suggest, the risk must be very low. But the point about sharing things like nail clippers is that you should avoid contaminated instruments, not that you should avoid them only if the risk is clear. Generally, you don’t want other people’s bodily fluids to mingle with yours via nail clippers, syringes, glass, razors, etc. The magnitude of the risk, in most cases, should be irrelevant.

  38. shazil February 21, 2016 at 4:18 am

    hi, i need a advice on act of protected intercourse with a CSW, it was protected but later after reaching home i found some of the vaginal fluid present on the left side of the girth of my slightly bent penis towards left its smell was really fishy so i can make after searching internet a lot that she might b suffering from bacterial vaginosis the thing thats making me worried is that i came to know women having bacterial vaginosis if hiv+ have higher concentration of hiv in their discharge moreover i dont have long penis just about 4 inches! considering her hiv+ should i be worried that the vaginal fluids could hav seeped to the tip of my flaccid penis

  39. Simon Collery February 21, 2016 at 9:06 am

    That sounds like a question for a GP or HIV counsellor, it is not something we would be in a position to answer. It’s always better to ask a specialist than to post the question online.

  40. Marie February 26, 2016 at 2:41 pm

    This is an interesting site, thank you.
    I’m really here as I am very very worried, as I stupidly used a 2 month old needle and spoon I fou d hiding in my flat, after I thought it had all been cleared out, as I got clean. But unfortunately had a very mad moment, and couldn’t controls .myself with putting this into my vein!!
    It’s Friday today, this happens on Wednesday morning. The sexual health cli nic is now closed. I did go there on Wednesday, but left, thinking whether to take pep or not, said if I do I will go back this morning before it closes, but its closed now. I feel Luke they needed me to tell me to take it for me to have taken it away then,but they said, it’s low risk so up to me!! Now I am panicking and not sure how to get through the time to wait for the test. They also said at the clinic how pep could be damaging to take, that’s why I thought I will be ok with out it.
    Tga k you for reading this, I do hope to hear something soon,
    Kind regards

    • Simon Collery February 28, 2016 at 5:25 pm

      If you are asking about the risk of HIV, it is likely to be very low from a needle that hasn’t been used for two months. Even if it wasn’t that long since it was used, it would depend on who used the equipment; if it was just you, you can’t infect yourself; if it was someone else, you don’t know if they are positive; either way, two months is long enough for many risks to be close to zero. There may be higher risks of other vjruses, infections, etc, so it’s worth talking to a medical practitioner or HIV counselor to help you assess your risk.

  41. Ratnakar March 12, 2016 at 3:08 pm

    Does surgical spirit kills HIV germs? What will be happen if I spray surgical sprit on floor , clothes, table or on tattoo equipments where some drops of HIV infected blood? Does it work if surgical spirit use for wash tattoo equipments.

  42. Simon Collery March 12, 2016 at 6:36 pm

    If you are using tattoo equipment you should make sure you have the proper hygiene. Instruments used to pierce the skin should be sterilized with steam or boiling water. I’m sure surgical spirit is useful for cleaning surfaces but I think it’s better to consult an expert. Use a registered and qualified tattoo artist; the same goes for anyone else who may be using skin piercing equipment of any kind. If you can’t find someone who is qualified, don’t get a tattoo.

  43. Steve April 14, 2016 at 7:02 pm

    I have an urgent question,
    I am getting hair behind my testicles and i was cutting it with scissors and i accidentally poked myself and a very small amount of blood came out, will that cause AIDS or HIV ?

  44. Simon Collery April 15, 2016 at 6:40 am

    Hi Steve, I don’t see how you could get HIV from your own blood. If that part of your body is exposed to the blood or bodily fluids or others who may be infected with HIV or any bloodborne virus you should take care, but the risk should still be very low. Even if the scissors were contaminated it is unlikely they would cause any problem either. But if you are worried you should see a HIV counselor and explain why you are worried.

  45. Kelly May 25, 2016 at 9:30 am

    Hello.. Two years ago I shared a nail clipper with someone and I got cut by it some blood came out of my toe but I put fire on the nail clipper before using it am I at any risk of hiv.. And after words I used the nail filler can hiv be pass through that thank you

  46. Simon Collery May 25, 2016 at 11:55 am

    Hi, what you write sounds like a very low risk indeed but if you are worried you should go to speak to an expert and even get a test, which is very quick and straightforward.

  47. sacha July 26, 2016 at 5:48 pm

    can one get HIV by being cleaned up with an infected cotton wool after blood was drawn up or taken for a test.

    • Simon Collery July 26, 2016 at 5:58 pm

      Using contaminated cotton wool to ‘clean up’ a wound would defeat the object of cleaning up, and you would be a lot safer to leave the wound alone if you only had dirty cotton wool. Most first aiders would probably tell you not to use cotton wool anyway, because it tends to leave particles of cotton behind, which can cause or exacerbate infection. There is probably a theoretical risk of being infected with HIV if the virus was present in large enough quantities, but if you have a genuine worry about such an incident it’s a good idea to talk to a doctor or HIV counsellor.

  48. sacha July 27, 2016 at 4:00 am

    maybe you did not get the question. I mean I went to a hospital to be tested of anaemia. my blood was taken . I think I was cleaned up with a stained cotton wool after and before the blood taken. it was not a wound . it was a needle used and as usual after drawing the blood the lab man told me to hold d cotton wool for a while to absorb the little blood coming out. I ask can some one get infected that way . I mean with a wool that was con terminated. its their any possibility of HIV getting back into the vein as little blood was already coming out.

  49. sacha July 27, 2016 at 4:02 am

    I cleaned up quickly with the cotton wool and threw it away but cleaned the spot where blood was drawn up from with my clean dry cloth

    • Simon Collery July 27, 2016 at 5:47 am

      Hi Sacha, I think it’s better if you go back to the hospital and speak to a medical officer in charge and explain the situation. The risk of being infected that was is probably very low but reusing contaminated cotton wool would breach guidelines in any hospital.

      • Anonymous August 3, 2016 at 2:16 am

        HIV virua died 30 second after being expose to air.However there is an exception with needle sticks. If you reuse a needle. There is a possibility for the virus to live for more hours.because the blood might be hidding in the needle where its not expose to oxygen.

  50. Jake August 3, 2016 at 8:32 am

    Hi anonymous, please can you provide the evidence for the claim that ‘HIV virua died 30 second after being expose to air’.

    • Simon Collery August 4, 2016 at 5:07 pm

      Hi Jake, you are right to demand evidence for the claim that HIV ‘dies in seconds’ as it is frequently been made, over a long period of time. It’s not even clear what it means! But Anonymous goes on to point out that the virus can live under certain conditions that make unsafe healthcare a very real risk for HIV transmission and even serious outbreaks, such as the one in Roka Commune, Cambodia, just last year. You’ll notice that the international HIV community dressed the outbreak up as an isolated incident and blamed a single unlicensed practitioner. But unsafe healthcare is widespread in developing countries and there have probably been many such outbreaks all over the world, and will be many of them in the future, given the reluctance of the HIV industry to admit that such incidents even occur, or represent the threat of rapid transmission of the virus to far more people than penile-vaginal sex ever could.

  51. Lindsay August 10, 2016 at 7:51 am

    I stepped on a piece of glass outside of a strip club in february, could I be infected with hiv

  52. kenedy August 19, 2016 at 8:34 pm

    on my hand there was scratching w/c is blooding due to an accidents and i used a toilet while iwas in toilet there was a dry blood on the one side which is touching me the my blooding area i saw it and i scared it so i wan to ask you if there was HIV in that dry blood can it dissolves and transmits to me ?thanks

  53. said August 13, 2017 at 8:00 am

    hiv risk from the thorns of tree what if. some eccidentaly pricks his hand and agin eccidentally another person pricks from the same thorns is a risk if hiv

  54. WorriedaboutHIV September 5, 2017 at 8:06 am

    Hello. Sorry to bother you. I was wondering if you could explan to me about my risk. I live in a country where HIV levels are high, yesterday I got food delivered in a metal container that had a lid made from foil. When I was opening the container, I sustained a paper cut type of injury from the edge of the foil lid. It bled a little and I washed my finger with water, then bandaged it.
    My question is this: if the cook also sustained a paper cut on the edge of that foil lid, the same place as mine, whould there be risk?
    The food was delivered hot, but to keep it warm, containers where wrapped in two plastic bags. So not sure how much air was there. I opened the container about one hour after it was delivered at the food was still very warm. Thank you.

    • Simon Collery September 5, 2017 at 8:26 am

      Hi, the risk sounds infinitesimal, but if you are worried you should go and see a health professional.

      • WorriedaboutHIV September 5, 2017 at 8:53 am

        Thank you. The reason it is small is it because the virus would probably be dead by that time or because if cook got a paper cut there would not be much blood on the foil? thank you again for sharing truth here

      • Simon Collery September 5, 2017 at 9:00 am

        The point of all the articles on this site is that you need to avoid exposure to the blood of other people, regardless of how you are exposed, and regardless of what viruses they may or may not have. It is impossible to calculate risk, especially very small risks like the one you mention. But it is a lot easier to enumerate the ways someone may be exposed to the blood of other people. So if you think you have been exposed you should contact a professional who can advise and test you, rather than attempt to calculate the uncalculable. Use the heuristic: avoid exposure to the blood of other people.

  55. rhitah September 12, 2017 at 9:34 pm

    Hello I need some medical help. Currently. I stay with my parents who are both positive with my 9minths baby. He love his grandmother a lotl but beloved to scratch people and.sometimes himself too. Enough to. See. Scratched lines with. Clotted. Blood. Days later. So what are the risks of infecting me and him. Worried mum.

    • Simon Collery September 13, 2017 at 4:57 am

      Hi, we are not medics so you need to talk to an appropriately qualified person face to face. They should be able to tell you about the many steps you can take to ensure that you and your family safe while you’re with HIV positive relatives.

  56. Surb J September 26, 2018 at 1:06 pm

    Getting pricked by a probe ( a dental instrument) which was not sterile only dipped in savlon what are the chances of getting HIV . Any vaccinations that i should go for or any test

    • Simon Collery September 27, 2018 at 7:53 am

      The message is that you don’t want unsterile instruments to be used on you, regardless of the risk. There are guidelines for a reason, and the person who pricked you with a probe was not following them. If you are worried you should see a healthcare professional, such as a GP.

  57. fridah December 16, 2018 at 6:46 am

    hello.i was in gloves .but i was using scisssors which were placed in normal saline that washes patient serum.i feel like i pocked my self with the tip of scissor.the gloves i checked we re not there a risk of getting infected

  58. ufuklarinotesi March 12, 2019 at 12:44 pm

    Hello, Last friday an African Black woman’s earring’s latch back sank to my nose, my nose bled a lot. I do not remember whether her earlobe hole bled or not. And also i do not know whether she has HIV+ or not. At that point my question is, if she had HIV+ and her earlobe bled(not like dorplets) is it possible to be infected with HIV? One infection disease disease doctor told me that the hole is already been epithelized so if there was a blood, it couldnot enough to infect you. Is that true?

    Could it be a superficial tissue exchange? And also the hole in the earlobe can easily bleed? Is there a situation that requires me to worry?

    Thank you for your answers,


  59. stella September 16, 2019 at 8:24 pm

    i was pierce with a needle hiv blood but the pierce did not bleed am i at hiv risk

  60. Simon Collery September 16, 2019 at 8:35 pm

    If you think you may be at risk you should go to see a health professional.

  61. Candy March 28, 2020 at 3:05 am

    Can someone answer what are the risk of getting hiv in this situation. A little girl whose has hiv has a very low viral count pricks her self with a thorn and my little girl pricks herself with the same thorn. No blood was exchanged as they both started bleeding at the same time. What are the chances of my little girl getting hiv.

  62. Simon Collery March 28, 2020 at 8:36 am

    If you think the girl has been exposed you should take her to a clinic to get advice. An estimate of the risk is irrelevant, get medical advice immediately.

  63. froland January 7, 2021 at 5:53 pm

    Many of the studies indicate that dried blood reduces the amount of virus.
    What is the minimum amount of virus necessary for it to infect?
    How much blood would that mean?

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