Blood donations by people taking drugs to treat, prevent HIV could be ‘cause for concern’
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Blood donations from people on antiretroviral therapy to treat HIV or pre-exposure prophylaxis to prevent HIV infection could increase risk for HIV transfusion transmission if tests cannot detect the virus in the donations, study results showed.
“Public health efforts to end the HIV epidemic through increased availability of antiretroviral therapy [ART] to treat HIV and pre-exposure prophylaxis [PrEP] to prevent infection are increasingly common,” Brian Custer, PhD, MPH, vice president of research and scientific programs and adjunct professor of laboratory medicine at Vitalant Research Institute in San Francisco, told Healio. “Our set of studies establishes that we do see blood donors in the U.S. taking ART to treat HIV infection, and separately we see HIV-negative blood donors who are taking PrEP. [Although] these are both forms of ART medications, the implications for blood safety have to be differentiated. It is important not to conflate ART use in HIV-positive donors and PrEP use in HIV-negative donors.”
Investigators performed blind testing for ART on blood samples from HIV-positive blood donors and a comparison group of infection-nonreactive donors using liquid chromatography-tandem mass spectrometry. They also tested blood donor samples for emtricitabine (Emtriva, Gilead Sciences) and tenofovir from a cohort of infection-nonreactive men aged 18 to 45 years who donated blood for the first time at six U.S. locations.
In addition, researchers assessed self-reported PrEP use around the time of blood donation among a cohort of men who have sex with men (MSM) included in the 2017 CDC National HIV Behavioral Surveillance (NHBS) from five U.S. cities.
Results, published in Blood, showed no detection of ART among 300 infection-nonreactive donor samples in blind testing. However, 46 of 299 (15.4%; 95% CI, 11.5-20) HIV-confirmed infected donor samples showed evidence of ART. Of those samples, 93.5% were from first-time donors and 74% were from men. Compared with blood samples from repeat or younger donors, samples from first-time donors and those aged 45 to 54 years with HIV appeared significantly more likely to show evidence of ART (P < .001).
In addition, nine out of 1,494 samples (0.6%; 95% CI, .03-1.1) from first-time male donors showed evidence of tenofovir and emtricitabine.
Among the 591 respondents to the NHBS MSM survey, 27 (4.8%; 95% CI, 3.2-6.9) reported PrEP use within the same time period of donating blood.
“The clinical implications [of the findings] are currently unknown,” Custer said. “The potential or cause for concern is that ART and PrEP by definition are taken to alter the course of HIV infection; thus, the use of ART or PrEP could impact our ability to detect HIV infection in donated blood because blood tests for HIV measure the presence of viral RNA or antibodies to HIV infection.”
This could lead to transfusion transmission of HIV, although there is no direct evidence of such transmission under these circumstances, he added.
“The concept of ‘undetectable equals untransmittable’ for sexual contact is very important from a public health perspective, but may not apply to donated blood because a transfused unit of blood is a much larger volume than would occur from body fluid exposure during sex,” Custer said.
Further research among larger cohorts is needed, Custer added.
“Much additional work needs to be done to understand if ART or PrEP use in accepted blood donors is changing over time and we will conduct additional work,” he said. “One would presume that with increased availability and distribution of ART and PrEP there is an increased chance that blood donors may be using these medications. We must conduct additional research to understand the magnitude of the use of ART and PrEP in blood donors by conducting larger studies of this topic. We are also actively pursuing studies to formally assess blood screening assays in participants who may be taking ART or PrEP.”
For more information:
Brian Custer, PhD, MPH, can be reached at the Vitalant Research Institute, 270 Masonic Ave., San Francisco, CA 94118; email: bcuster@vitalant.org.
Perspective
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Paul A. Volberding, MD
The interface between the HIV epidemic and blood donation is long and complex. Blood is an essential resource and we encourage volunteer donations, which are for the public good. On the other hand, we want a blood supply that has as close to no risk for transmitting HIV (and other dangerous infections) as possible.
Before HIV testing was available, we relied on self-deferral for those considered at higher risk for HIV infection, including MSM and injection drug users. Deferral of blood donation based on sexual activity has continued, although the duration of reported abstinence has been reduced, but we primarily rely on current generations of HIV screening assays that are extremely accurate. By these means, the risk for acquiring HIV from donated blood has almost been eliminated.
Recently, however, concern has been raised that individuals with HIV infection or at higher risk may still donate blood, perhaps in response to social pressure from others unaware of the HIV status of a friend or co-worker. Additional concern surrounds the possibility that ART or PrEP may affect this issue. We accept the mantra ‘undetectable equals untransmissible’ in a sexual context but would still hesitate to accept a transfusion from an infected donor even if the virus were undetectable. We might also be concerned that a donor who felt the need for PrEP because of sexual activity might be at a higher risk for being in the narrow but real “window” between HIV infection and test positivity.
The authors of the current report in Blood, some of whom are on the faculty of University of California, San Francisco, took an interesting approach to this issue by searching for blood levels of antiretroviral drugs in blood donors found to be either HIV test-negative or HIV test-positive at donation, as well as first-time young male donors who were HIV test-negative. They also analyzed results of a questionnaire about PrEP use among donors from another study among MSM.
In general, the results are reassuring. PrEP medications were detected in 0.6% of first-time donors. But antiretroviral drugs were detected in 15.4% of donors found HIV test-positive, and in the questionnaire, 4.8% of respondents reported PrEP use at or close to the time of donation. It appears that individuals being treated for HIV infection or taking PrEP are still at least occasionally donating blood.
The take-home message of this study would seem to be to continue our current screening, which has dramatically decreased the risk for HIV infection from transfused blood, while redoubling our educational efforts to convince those with or at higher risk for infection to avoid donation. Blood safety is a vital concern, and maintaining our vigilance while still encouraging and rewarding donation remains deserving of our attention.
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