Around the world organizations that seek blood donations usually have a policy to discourage men who have sex with men (MSM) from donating blood. This is due to the risk of Human Immunodeficiency Virus (HIV) in the blood.

This is reliant, of course, on those men reporting they have sex with men before donation to have themselves excluded.

On Wikipedia I have found that an estimated 14% of MSM are infected with HIV but I haven't found information about how good the testing processes for donated blood happens to be to detect infected blood.

As pointed out in the comments, there are other sources of HIV infected blood. And, what about those who don't know they are infected?

Given current testing standards for donated blood, what are the chances of such a blood donation infecting the receiving person with the HIV?

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    Why do you ask this question in the context of homosexuality? There are plenty of sources of HIV infection other than homosexual men. In some parts of the world heterosexual married women are important sources. Wouldn't it be more appropriate to simply ask how effective HIV screening of blood donations is?
    – Carey Gregory
    Apr 23, 2021 at 2:09
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    @CareyGregory I ask the question because I want to know whether the ban on donating blood is backed by rational reasons or whether it's an outdated policy (and thus the policy unfairly discriminates against homosexuals).
    – Christian
    Apr 23, 2021 at 10:31
  • @Carey Gregory I think we should rephrase it so it doesn't come off as offensive? Who better than a moderator can make a nice edit?
    – Desai
    Apr 24, 2021 at 20:32
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    @Desai You could also do it.
    – Carey Gregory
    Apr 24, 2021 at 21:45
  • As there does seem to be a bias against MSM I left that part in the title but edited this to make the question less prejudicial. Hopefully this fits with what you are asking. If not, feel free to make further edits. Apr 29, 2021 at 7:56

1 Answer 1


TL;DR — The transmission of HIV through blood products is very rare, but examples have occurred in some low-income countries which lack the equipment to test all blood.

You said:

Around the world organizations that seek blood donations usually have a policy to discourage men who have sex with men (MSM) from donating blood. This is due to the risk of Human Immunodeficiency Virus (HIV) in the blood.

This is not entirely accurate. There have been blanket bans in the past with regard to MSM blood donations in the US and the UK. I am unsure on the US, but in the UK the ban included women who have had sex recently with a man who has sex with men. However, there have been changes in the rules to remove restrictions in certain circumstances.

Other countries have followed suit.

Other countries have similarly amended MSM-specific restrictions on blood donation in the past decade, including Argentina, Bolivia, Chile, Israel, Mexico, Peru, and South Africa. In 2016, France began allowing MSM to donate apheresis plasma under the same policy as other donors (ie, plasma from people with more than one recent sexual partner is quarantined for at least 2 months until the donor can return for HIV retesting). Then, in 2019, the country announced whole blood donation regulations would be aligned for gay and straight donors by 2022. In 2020, both Hungary and Brazil repealed bans on blood donation by MSM, with Brazil's Supreme Court ruling that such restrictions were unconstitutional (Skelly, et al. 2020).

Bans such as this rely on self-reporting donors, and the FAIR report on BBIs from MSM blood donation (which I talk about later - in the UK section) even covers the fact that there is non-compliance in positive donors reporting sex between men.

HIV vs other blood borne infections (BBIs)

The thing is, there are many other BBIs other than HIV which are a cause for concern for the Blood Transfusion teams around the world. Among others, there is syphilis and hepatitis. And, just like with these BBIs, there is more than one way to get HIV other than a man having sex with another man.

What are the chances of receiving blood infected with BBIs

Avert — a UK-based charity that has been providing accurate and trusted information about HIV and sexual health worldwide for over 30 years — points out that in order to prevent transmission of BBIs, international health regulations require all blood products, such as organs or tissues, to be screened for a number of viral or bacterial contaminants before they are used.


During the screening process any blood products which contain HIV, hepatitis B, hepatitis C, or syphilis will be disposed of.

This means that the transmission of HIV through blood products is very rare, but examples have occurred in some low-income countries which lack the equipment to test all blood (Avert, n.d.).

In the US

In 2015, US policy changed from a lifetime ban on donations (‘indefinite referral’) from any man who reported having sex with another man after 1977, to a 12-month deferral period. This means that men who last had sex with another man more than a year ago are eligible to donate blood, while men who have had sex more recently are not (AIDS Map, 2020).

Referring to the Conference on Retroviruses and Opportunistic Infections (CROI 2020), there was a study (Grebe, et al. 2020) which found that

  • HIV incidence in first-time donors was similar before and after implementation of the 12-month MSM deferral, both overall and in males.
  • The residual risk of HIV transfusion transmission for components sourced from first-time donors was low and did not change significantly.
chart of incidence differences
image from page 50 of CROI 2020 Oral Abstracts PDF Book
Bivariable and multivariable Poisson regression models using data from the entire TTIMS period showed that MSM deferral policy was not a significant correlate of incidence, although male sex (risk ratio 5.0, 95% CI: 2.8–9.5), age 18-24 (RR: 4.3, 1.5–18.3), black race (RR: 10.1, 5.8–17.9), Hispanic ethnicity (RR: 2.6, 1.3–5.0) and Southern region (RR: 2.0, 1.4–7.9) were significant (CROI 2020 Oral Abstract).

It was concluded that:

There is no evidence that the implementation of a 12-month MSM deferral policy resulted in increased HIV incidence in, and therefore transfusion transmission risk from, first-time blood donors in the United States

In the UK

The criteria that are used by the UK blood services to select blood donors on the basis of behaviours that may increase the risk of acquiring and transmitting blood borne infections (BBI) last underwent major review by SaBTO [Advisory Committee on the Safety of Blood, Tissues and Organs] in 2011. That review led to a change in selection criteria for potential blood donors who are men who have sex with men (MSM). The selection criteria were changed from a permanent deferral to a twelve month deferral from last sexual contact in England, Scotland and Wales Blood Services in 2011, and by The Northern Irish Blood Transfusion Service in 2016 (UK Government, 2017).

In December last year, the UK Government announced a further change in the rules to allow more gay and bisexual men to donate blood in the UK (National AIDS Trust, 2020) and the UK Government state that changes will take place by Summer 2021 and will have no impact on the safety of blood donated in the UK (UK Government 2020).

NHS Blood and Transplant (NHSBT) led a steering group called FAIR (For the Assessment of Individualised Risk).

FAIR membership includes representatives from the four UK blood services (NHS Blood and Transplant, Scotblood, the Welsh Blood Service and the Northern Ireland Blood Transfusion Service), Public Health England, Nottingham University, the National Aids Trust (NAT), Stonewall, Freedom to Donate, Terrence Higgins Trust (THT), and includes experts in epidemiology, virology and psychology and other key stakeholders (NHSBT, 2020).

It was set up to consider how risk could be assessed on a more individual basis when people go to donate blood.

New criteria, based on findings from the FAIR report (FAIR, 2020), focuses on individual behaviours, and lifts a blanket deferral for men who have had sex with men in the last 3 months.

The FAIR (For the Assessment of Individualised Risk) steering group has recently concluded that donors who have had the same sexual partner in the last three months and who don’t have an STI should be eligible to donate (NHSBT, 2020).


AIDS Map (2020). No increase in HIV in blood donations since rules for gay men were relaxed https://www.aidsmap.com/news/mar-2020/no-increase-hiv-blood-donations-rules-gay-men-were-relaxed

Avert (n.d.). Blood transfusions & transplants and HIV https://www.avert.org/hiv-transmission-prevention/blood-transfusions-transplants

CROI (2020). Conference on Retroviruses and Opportunistic Infections 2020 https://www.croiconference.org/croi-2020/

FAIR (2020). Can donor selection policy move from a population-baseddonor selection policy to one based on a more individualised risk assessment? Conclusions from the For the Assessment of Individualised Risk (FAIR) group https://nhsbtdbe.blob.core.windows.net/umbraco-assets-corp/21001/fair_sabto_20201211.pdf

Grebe, E., Busch, M. P., Notari, E. P., Bruhn, R., Quiner, C., Hindes, D., ... & Custer, B. (2020). HIV incidence in US first-time blood donors and transfusion risk with a 12-month deferral for men who have sex with men. Blood, The Journal of the American Society of Hematology, 136(11), 1359-1367. https://doi.org/10.1182/blood.2020007003

National AIDS Trust (2020). Changes to blood donation rules explained https://www.nat.org.uk/blog/changes-blood-donation-rules-explained

NHSBT (2020). Blood donor selection policy: the work of the FAIR steering group https://www.blood.co.uk/news-and-campaigns/news-and-statements/fair-steering-group/

Skelly, A. N., Kolla, L., Tamburro, M. K., & Bar, K. J. (2020). Science over stigma: the need for evidence-based blood donation policies for men who have sex with men in the USA. The Lancet Haematology, 7(11), e779-e782. https://doi.org/10.1016/S2352-3026(20)30326-4

UK Government (2017). Donor Selection Criteria Report (2017) Version 2 https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/809909/sabto-donor-selection-criteria-report-2017-v2.pdf

UK Government (2020). Landmark change to blood donation criteria [Press Release] https://www.gov.uk/government/news/landmark-change-to-blood-donation-criteria

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    The current policy of the 12 month deferral suggests a belief that blood screening is not good enough to do without a deferrel period. That's might be backed by evidence or not and your answer doesn't tell us whether just lifting the deferral period would be warrented.
    – Christian
    Apr 29, 2021 at 18:50
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    @Christian What about the citations I put in at the beginning if the US section? Plus, the Skelly article argues the case for the US to follow suit with what the UK have recently put into place. So I cannot see how it can be assumed that blood testing is inadequate. Especially also, with Avert's assertions that the cases of HIV transmission is more likely in low-income countries. Apr 30, 2021 at 10:34

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