I came across your page via Medhelp where I've already asked Dr Hook a question - he answer was very reassuring and has put my 'incident' into perspective but I just wanted to check...
a) while I'm here, would you agree with the answer below, that toothbrush incidents are virtually no risk and given I didn't know whether the girl has HIV or even used my toothbrush, it really is a no risk event and I'm going slightly mental..?!
b) if I can't get this out my head and need a test - I'm going on holiday next week so the latest I could do a duo is 23 days, unfortunately. I know 28 is recommended and better but have also heard the duo is probably also very accurate a few days before this. Could you please give me an idea of what sort of % reliability we would be looking at around 23 days?
Many thanks,
Ed
I’m a 26yo hetero male from the UK who started a relationship with a girl a few months ago. I didn’t want to do anything to jeopardise our relationship or her health, so got an STD & HIV test – all negative.
I’ve had some sporadic anxious spells over HIV in the past, perhaps triggered by certain experiences including one of my friends becoming HIV+. Since my test I’ve become fixated on one event which I’ve seen addressed here before, although it will genuinely help to hear a real professional address the specific risk of my incident…
A week ago I stayed at my gf’s house and think I left my toothbrush in her shared bathroom overnight. Q- Is there any risk at all that one of her housemates could accidently use my brush and transfer HIV to me? If it makes any difference, the one housemate who generally uses that bathroom is a lesbian from Canada...
Although the risk from a brush may be zero practically speaking, it helps me to break down the chain of events and illustrate why the odds are so low with a quantified figure, even if there was some faint chance of transmission this way (the ‘worst case scenario’)… I’ve attempted to do so using conservative figures…
1. probability that a lesbian from Canada with no other risk factors (e.g. IDU) has HIV = 1/100 (I have no idea on lesbian infection rates – could you suggest a figure please?)
2. probability that she accidently used my brush that night = 1/100 (conservatively suggesting she could do so every 3 months..)
3. probability that using the brush once would transfer HIV = 1/1000 (imagining the same as hetero sex, which I appreciate it isn’t – ‘zero’..)
= 1 in 10 million
Could you please look at the figures I’ve used and tell me if they are conservative enough? If so, and the risk is therefore 1 in 10 million or less, I think I can put this one to bed! More chance of getting struck by lightening… presumably you’re advice is to forget about it, and move on?
Many thanks
Ed
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Twitter ..Doctor's Answer by Edward W Hook, MD, May 11, 2011 06:13AM
Welcome to the Forum. I'll try to put your anxieties to rest. We have answered questions of this sort many times on this Forum. There is no meaningful risk of HIV from the situation you describe.
The figures you have used are overly conservative. For instance, most available data indicate that lesbian women have an HIV rate which is lower for heterosexual women; the rate for heterosexual women in North America who are not IV drug users is between 1 in 1,000 and 1 in 10,000 at most, not the 1 in 100 you suggest for lesbian women. Similarly, the most conservative figures I know of for transfer of HIV through oral sex (again, which are higher than for infection through a shared toothbrush which has NEVER been associated with HIV infection) is 1 in 10,000, not 1 in 1000 as you suggest. Thus, the risk of infection through use of a shared toothbrush is far lower than the 1 in 10 million you suggest and far lower than your chance of getting struck by lightning. The situation you describe has NO meaningful risk for acquisition of HIV.
Dear Ed,
Thank you for your post and welcome to our forum.
I totally agree with my colleague, Dr Hook.
There is no real risk of contracting HIV through sharing a toothbrush and as you say, you do not know the status of this lady. It is far much more likely that she is negative anyway and you are worrying unnecessarily.
For this reason, you do not even need to be tested. However if you still want to have a test, if you were to do a HIV Duo test at 23 days, you can consider it conclusive as it would have an estimated reliabilty of over 98-99%. The p24 antigen is already detectable after 14 days.
Best wishes,
José
Thanks very much for your response - I’m feeling pretty good about this after the assurance from yourself and Dr Hook. Rationally speaking I know I’m fine but if it’s still floating around my mind a bit next week, a test with that level of reliability should kill it… they have helped me immensely on a couple of occasions in the past.
One further question though – does the duo ever turn up false positives? And if it did, how long would it take to confirm whether a positive result is true or not? I ask because obviously I want to have a totally clear head when I’m on my holiday… hence the test… but a false positive that lasts a few days would have the opposite effect!
False positives are very rare and in the case of an initial reactive result, the sample is always sent for additional confirmatory tests, which in the case of a false positive result, these would be negative. Therefore in any case, you would definitely have a definite answer.
Best wishes,
José
toothbrush + testing
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