[Question #7436] Recent study

3 months ago
Drs Handsfield and Hook,

I hope this is a very quick question, thankyou much for taking time to review this. I have read many your posts on here and they given me much reassurance. In particular, I had friend from a high-risk country (for HIV, Hepatitis B and C) stay with me and my family for a month (I live in developed western country). He's since gone but I'm very worried now he shared one of my family members' razor or toothbrush, I read your answers to other posters saying this obviously is a bad idea for future reference, but for retrospective worrying  the overall risk of an STD or bloodborne disease was not worth worrying about (even if they had been infected).

Also I read Dr Handsfield say there are no other medical conditions which would increase risk of transmission via sharing of non-sexual objects. This reassured me fully, as my family has a few serious medical conditions.

However I read this study just now - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6884859/ - which says conditions like malaria or worms can increase risk of HIV transmission? This is a recent study from November 2019 so wondered if would change any of your previous advice for such transmission of STDs or any bloodborne diseases like HIV or Hepatitis B or C?
I think though reading it this is saying the increase in risk is due to these other conditions impacting the body immune system when resisting HIV, rather than the risk of transmission from person-to-person? So am I fine to rely on previous advice on here and assume this does not change risk via non-sexual household transmission?

Thankyou Drs much in advance
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
3 months ago
Welcome to the forum. Thanks for your very interesting question and for the citation. It's not actually a new study, but a scientific review of other research reports. On quick scan it appears to be an excellent, scientifically valid review. I'm taking the opportunity for a blog-like reply that might be useful for forum readers and to be cited in response to similar questions in the future.

There are several infections that increase the risk of HIV infection if exposed. On a worldwide basis, the most important is type 2 herpes simplex virus (HSV2), the main cause of genital herpes. On average, people with HSV2 have twice the risk of catching HIV if sexually exposed. Similarly, the risk is elevated in the presence of gonorrhea, chlamydia, and probably other STDs -- specifically those that cause inflammatory responses in the genitals, rectum, etc. The idea that other infections, such as malaria, have similar effects is well known, and the possible biological mechanisms are discussed in the article you cite. 

All this is dfferent than medical conditions of the sort have asked about on this forum. To my knowledge, there are no data to indicate a higher risk of HIV acquisition in people with cancer, autoimmune conditions, or other health problems. Few studies have been done, however, and I would never say never. However, any such effect likely is small -- otherwise it likely would have been obvious from simple epidemiologic studies. But as far as I know, there have been no reports of higher HIV acquisiton rates in people with such conditions -- unlike the situations with HSV2, other STDs, malaria, and perhaps other conditions (also discussed in the article cited). That malaria-induced inflammation might have a genital or rectal component doesn't necessarily imply that many other conditions (such has viral hepatitis) have similar effects. (The immune responses to various infections are highly different from one to the next -- and malaria is a prime example of a disease with broad, multifaceted immune defenses.

Finally, let's say there is in fact an increased risk of acquisiton in people with, say, hepatitis B or C. At a personal risk level it probably makes no important difference. As noted above, the risk with HSV2 is double, other things being equal. A two-fold higher risk seems a big deal, but how much difference does it make following any particular exposure? Most of the exposures described on this forum re very low, e.g. 1 chance in a million or less. Doubling that risk makes 1 chance in 500,000 -- still zero for practical purposes. Another way to look at it is that at a population level, the influence of HSV2 is huge -- because HSV2 is so common. These data imply that if HSV2 could be eliminated from the equation -- say an effective vaccine someday -- the worldwide frequency of HIV would be cut in half.But still not much change in risk or prevention advice at the individual level. For what it's worth, similar considerations apply to circumcision:  being uncircumcised, like HSV2, roughly doubles the risk of HIV after penile exposure -- and for the same reasons, circumcision is now a prominent recommendation for HIV prevention, especially in sub-Saharan Africa.

These points have been made many times on the forum and our advice, going forward, won't change.

Thanks again for raising this issue. Let me know if anything isn't clear.

HHH, MD
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3 months ago
That is great Dr thankyous very much, such a helpful and detail response. This explains it so very well. So I am right that this study would not change materially any of the previous advice/responses you & Dr Hook have given on this site over the past 4-5 years? (timeframe of previous responses I read)
And from your detailed answer, conditions like cancer or Crohn's disease that compromise the immune system or require strong immunosuppressants would have no material impact on the risk of someone contracting STDs or bloodborne viruses through non-sexual/non-needle exposures?

Thankyous again Dr very much.
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
3 months ago
Thanks for the thanks. I'm glad my comments have been helpful.

Dr. Hook and I of course cannot remember every response we have given the past few years, but I am unaware of any adcvice about HIV risk assessment that we would change. Correct that I am unaware of any data suggesting a higher risk of HIV, other blood-borne infections, or STDs in people with immune compromising diseases or drugs, or with cancer or Crohn's disease, either sexually or by injection drug use or needle exposure.
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3 months ago
Thanks again so much Dr. Very helpful to know. Sorry think I didn't make myself clear, I apologize. I have only several more questions:

a) When you say this study would not change any of your advice on HIV risk, this also applies to STDs and bloodborne viruses for example Hepatitis B and C?

b) On non-sexual/non-needle contact (ie household transmission) - yours and Dr Hook's previous answers to other posters said sharing razors or toothbrushes obviously is a bad idea for future reference, but for retrospective anxious worrying the overall risk of an STD or bloodborne disease such as HIV, Hepatitis B or C was not worth getting anxious about (even if they had been infected).
So given your very helpful answers here on this study, and other medical conditions, I am right to think such previous advice would not change as a result of this study, regardless of any medical conditions either party had?

c) I am right to think that even if either party had any of the conditions listed in the study (e.g. malaria, helminths) it would not materially change the real-world level of risk for sharing razors or toothbrushes (or other household transmission) given this level of risk is already low? So this study would not materially change your/Dr Hook's previous advice on this site for the risk of STDs or bloodborne disease such as HIV/Hepatitis when sharing razors or toothbrushes or other non-sexual household items?

Thankyou many times again Dr. For explaining everything so well and patiently.

H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
3 months ago
a) When you say this study would not change any of your advice on HIV risk, this also applies to STDs and bloodborne viruses for example Hepatitis B and C? Correct.

b) "On non-sexual/non-needle contact (ie household transmission)...?" Also correct. Our advice has never changed and is not likely to change.  

c) "I am right to think...?" Yes, also correct on all counts.

That completes the two follow-up exchanges included with each question and so ends this thread. I hope the discussion has been helfpul.
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