Regulations governing blood donation and transfusion in Brazil are very similar to those in the US and Europe, and internationally accepted procedures and guidelines are used as reference in the development of Brazilian rules and practice guidelines. However, the risk of HIV transmission by blood transfusion persists in Brazil and remains higher than in the US and most European countries (1)

As in Australia, Canada, USA, and several European countries, The Brazilian Ministry of Health changed the regulation for permanent deferral from donation for men who have sex with men (MSM) to be a 1-year deferral since last sexual contact (2, 3). In the UK, MSM donation deferral is now three months after the last sexual contact. Countervailing to the easing of policies, Spain is considering changing their MSM non-deferral policy to a temporary deferral based on individual risk assessments due to the potential risk. In Brazil, there are proceedings in front of the Supreme Court at this time that would compel all blood collectors in the country to change some predonation interview criteria, including not allowing blood centers to ask donors whether their sexual partners are the same or opposite sex, or inquiring about other aspects of the donor’s sexual partners. There are no available data to understand what possible alternative questions would be appropriate to reduce the risk of donation by persons with high risk for infection.

HIV/AIDS is a global epidemic that is dynamic and changing, so the risk is not evenly distributed, varying by risk profile (4, 5). While the routes of HIV infection acquisition are known, the contextual factors such as how and where persons meet their sexual partners, sexual attitudes and the impact of the numbers and different type of partners are less well known. Several studies of risk factors for HIV infection conducted in the Brazilian population report sexual transmission as the main cause of cases of HIV/AIDS, with most cases attributed to unprotected sex between MSM. However, there are also other routes of acquisition observed in Brazil, including intravenous drug use and unprotected heterosexual sex (6). Risk factor studies in blood donors have shown that MSM remains the strongest determinant of HIV status among HIV positive blood donors (1, 6–9).

We analyzed data from a HIV behavioral risk factor case-control study from the Retrovirus Epidemiology Donor Study – II (REDS-II) to assess whether it is possible to identify high-risk behaviors among HIV positive donors and their partners and to assess alternative questions that could predict if a blood donor is at risk of being HIV positive, regardless of sexual orientation. Our study sought to assess whether surrogate risk behavior questions can predict if a blood donor is likely to be HIV-positive or negative. Additionally, the social and sexual behavior of blood donors and their partners were also evaluated to better understand risk behaviors for HIV infection.

The REDS-II Brazil HIV case-control study population includes 838 male respondents whose data were used in this analysis. Descriptive statistics for all of the 838 male donors, including the subset of 799 with ACASI questionnaire responses are provided (Table 1). Respondents had a mean age of 33.6 years, 596 (71.5%) completed elementary school, 433 (51.7%) were married, and 666 (79.5%) reported heterosexual partnerships in the past 12 months and, 90 (10.7%) reported having 6 or more partners in the past 12 months. Of the 799, 793 answered the questions from the sexual matrix on their recent sexual partners (Figure 1). About 10% had at least one partner with a ten or more years’ difference of age. Most of blood donors reported to have a main partner (75.0%). Four percent reported IVDU or being a sex partner of an IVDU. Thirteen percent reported having at least one MSM partner among the last five partners. More than one-third (35.8%) reported that they did not know about their partner’s HIV status and 4.0% answered that they had at least one HIV-positive partner in the last 12 months. Thirty percent of the respondents disclosed that they met their partner(s) at social/political events, in clubs, or church. More than two-thirds (66.7%) reported unprotected vaginal sexual encounter and more than one quarter (27.2%) reported unprotected heterosexual anal sex with at least one of the last five partners in the last 12 months.

We evaluated blood donors who tested positive and negative for HIV in blood centers from four locations in Brazil. Latent class analysis revealed three classes, with distinct levels of risk behavior. Two Classes (1 and 2) with differing HIV status were very well described with dissimilar behaviors, but Class 3 with mixed behaviors, had the same proportion of HIV positives and negatives. The Class-3 is predominantly a group of heterosexual, unmarried donors, with multiple sexual partners who are having unprotected sex. Therefore, a closer look at this group is needed, since almost half of these individuals are potentially eligible blood donors and can return for new donation. Some characteristics of donors’ sexual partners such as age, type of partner, as well as where donors met their partners may directly affect the risk of being HIV positive. Thus, an understanding of respondent’s sexual networks may be extremely useful to improve predonation interviews currently used to select eligible blood donors.

In Class-1 most donors informed practicing unprotected sex. However, most also reported to have one main partner, explaining why donors in this class are HIV-negative. Despite unprotected sex representing a source of HIV risk in many contexts, our study shows that this could be viewed as a protective factor by virtue of it being an indicator of lower number of sexual partners in Class-1 members when compared to the other Classes (16).

Class-2 was defined by donors who did not know the HIV status of their partners. Previous studies have shown that a large number of HIV-positive persons, especially young people, engage in unprotected sex with casual partners with unknown HIV status (17–19). The HIV status disclosure to sex partners is very complex and influenced by gender, anticipated support, fear of rejection and sociocultural context such as stigma/rejection (20). The lack of support and fear of rejection are less likely to occur in individuals with main and steady partners, so probably the type and number of sexual partners also contributed to the disclosure of HIV status. In some settings HIV positive persons are encouraged or legally expected to disclose their HIV status to their partners as a strategy to reduce HIV transmission (21, 22). Currently, this is not the situation in Brazil. Nonetheless, more studies are needed to understand the influence of knowledge of HIV status on sexual partnerships and what factors influence the disclosure of HIV status. Class-2 also reported to have met their partners in dating services (internet/ads) or in a bar/carnival, being the only class in which the meeting venue clearly defined the class’ profile. A recent study has pointed out that there are more risky places than others for risk of sexually transmitted infection, and some people gather at these sites to find potential sexual partners. As a cluster, many individuals at risk and who attend these venues constitute the “risk environment” for HIV acquisition (23). This was evident in our study even though it was not defined as an objective of the original REDS-II HIV case-control study.

The random forest analysis showed that the sensitivity values would decrease minimally if direct questions about sexual orientation of blood donors were removed from predonation interviews. When we remove questions about sexual history and partner’s type together but keep the partner’s HIV unknown status in the model, we achieve reasonable values. The knowledge about sexual partner(s) HIV status followed by other questions were a strong predictor for donor’s HIV status. Mathematical models show that HIV status disclosure can directly impact HIV transmission risk and that individuals who disclosure their HIV status are less likely to have multiple sex partners and more likely to use condoms (24–26). Removal of questions about sexual orientation and type of sexual partners does not entail significant losses in sensitivity, specificity and PPV of the models to predict whether donors are HIV positive. However, if the question about HIV status of sexual partners was included as a criterion for donor eligibility, the number of deferrals for persons who do not know their sex partner’s HIV status could potentially increase to an unacceptably high proportion. A previous study suggests that extensive questioning of blood donors about their sexual behavior may lead to the loss of existing donors who may find the process invasive (27).

This study has some limitations. The original case-control study included a convenience sample of HIV cases and a probability sample of controls. The behaviors and characteristics of the respondents may or may not reflect all HIV-positive and infection-negative donors in Brazil. We conducted this analysis for males only, and so the same questions may or may not be capable of predicting HIV-infection risk in females. Because of the context of HIV risk and sexual orientation it was necessary to focus just on male respondents to asses if there are differences within the male blood donors and to measure the impact of the possible changes in the deferral policy for MSM in Brazil. In addition, we have generalized our findings for the participants from the four blood centers in Brazil, assuming they are representative of male donors throughout the country. Despite these limitations, this study represents one of few in the field of sexual networks in blood donors and points out further studies in this domain to guide changes in blood donations selection are necessary.

We conclude that LCA methods can assess the interaction of multiple risk factors that place individuals at different levels of risk for acquiring sexual transmitted infections, including HIV. This type of assessment is not possible with regular regression methods, but shows that use of LCA can help to improve clinical screening and blood donor selection. In our study, HIV positive blood donors have a homogeneous pattern of behavior, with very well-known high-risk behaviors. With exception of the Class 3 profile with blood donors that are engaged in mixed high and low-risk behaviors, the study did find compelling results for questions that could reliably differentiate between lower and higher risk blood donors, an unresolved challenge in donor selection. A tendency emerging in some countries, such as Spain, Italy and Portugal, is to select blood donors based on individual risk assessments, that can include partners with unknown risk behaviors, new or multiple partners, and not to consider just if a sexual partner is the same or opposite sex (3, 28). We do not know what the impact of this approach would be in Brazilian blood services. Considering that blood donor selection in Brazil is performed via face-to-face interview and based on epidemiological data about well-known high-risk behaviors, we recognize it would not be easy to change to other approaches to donor eligibility questioning. Research to understand barriers to such change would need to be completed to ensure the adequacy of the blood supply would not be adversely affected. Nonetheless, we conclude that direct or indirect questions about sexual orientation used in the selection of blood donors could be replaced by an inquiry into the knowledge about sexual partner’s HIV status. Thus, while this study shows changes to donor questioning can differentiate between higher and lower risk donors, we believe it is premature to move to new donor eligibility questions in Brazil that have not been studied to assess donor comprehension and acceptability.