HIV incidence and compliance with deferral criteria over three progressively shorter time deferrals for men who have sex with men in Canada

HIV incidence in US first-time blood donors during 12 and 3 month deferral policy periods between 2015 and 2023 before implementation of individual donor assessment

BACKGROUND

Following FDA guidance, US blood collectors changed donor deferral for men who have sex with men (MSM) from indefinite to a 12 month deferral in 2016 (12 m), and for MSM and several other exposure risks to 3 month deferrals in 2020 (3 m). We evaluated first-time donor (FTD) HIV incidence and demographics during these periods.

STUDY DESIGN AND METHODS

We estimated cross-sectional HIV incidence and incidence rate differences in FTD based on routine donation nucleic acid testing (NAT) and serology with additional limiting antigen (LAg)-Avidity immunoassay and viral load testing. We estimated incidence in the two policy periods (12 and 3 m), incidence trends in two-year intervals between 2015 and 2023, and used multivariable Poisson regression to assess demographic correlates of incident infection.

RESULTS

HIV incidence in FTD during the 12 m deferral period was 2.82 infections/105 person-years (PY) [95% CI: 2.12, 3.67] and during the 3 m deferral period, it was 1.88/105 PY (95% CI: 1.18, 2.67), a statistically significant decline (p < .05). Over the period 2015-2023, incidence was stable. Male sex, younger age, Black or African American race, Hispanic ethnicity, and residence in the South were associated with incident infection in regression analysis, but the time-based deferral policy periods were not.

DISCUSSION

HIV incidence in FTD did not increase between 2015 and 2023. An overall decline in HIV incidence in the 3 m deferral period compared with the 12 m deferral period was evident. These results provide no indication of an increased residual risk of transfusion-transmitted HIV from FTD in the United States with the reduced deferral periods.

Assessing HIV trends among blood donors in five Brazilian blood centers: The impact of individual donor assessment

BACKGROUND

In many countries, including Brazil, time-based blood donation deferral policies for gay, bisexual, and other men who have sex with men (gbMSM) have been replaced by individual donor assessment (IDA). We examined HIV prevalence and incidence among first-time (FTD) and repeat donors (RD), comparing data from ~3.5 years before and after the IDA policy implementation in 2020.

STUDY DESIGN AND METHODS

The Recipient Epidemiology and Donor Evaluation Study-IV-Pediatric (REDS-IV-P) Brazil component collects blood donor screening data from five public centers. From January 2017 to December 2023, we report frequencies, rates, and 95% confidence interval (CI) of confirmed HIV-positive donations among FTD, HIV NAT-yield rates for FTD and RD, and the incidence of confirmed HIV among RD before and after the policy change. We also report multivariable regression analysis results.

RESULTS

Confirmed HIV prevalence in FTD was 79 per 100,000 (95% CI 72-87) before and 100 per 100,000 (95% CI 90-109) after the policy change, with differences between centers. HIV NAT-yield rates decreased for RD (p = .0025), with no change for FTD (p = .3). HIV incidence in RD did not increase (12.4 [95% CI: 11.1-13.9] vs. 10.3 [95% CI: 9-11.7] per 100,000 person-years).

DISCUSSION

Our findings showed no significant difference in HIV incidence among RD. Although HIV prevalence among FTD increased, there was no rise in HIV NAT-yield donations. The analysis highlights challenges in interpreting changes within specific groups and blood centers, underscoring the importance of multicenter monitoring of transfusion-transmitted infections.

Impact of recent criteria changes for the deferral criteria specific to men who have sex with men in France

BACKGROUND AND OBJECTIVES

In 2016, France allowed men who have sex with men (MSM) to donate blood if they had not had sex with men in the previous 12 months. In April 2020, this restriction was relaxed to 4 months due to the lack of negative impact observed on blood safety. This study assesses the impact of reducing this deferral period on epidemiological surveillance indicators.

MATERIALS AND METHODS

This study compares infection surveillance indicators between two 30-month periods before (P1) and after (P2) this second deferral change.

RESULTS

Overall, 79 donations tested positive for human immunodeficiency virus (HIV) (49 in P1 and 30 in P2), 322 for hepatitis C virus (HCV) (185 and 137), 622 for hepatitis B virus (HBV) (355 and 267) and 1684 for syphilis (799 and 885). Positive donation rates decreased between P1 and P2, except for syphilis: HIV (0.07/10,000 donations vs. 0.04; p > 0.5), HCV (0.25 vs. 0.20; p < 0.05), HBV (0.49 vs. 0.39; p < 0.01) and syphilis (1.10 vs. 1.29; p < 0.001). For all three viruses, residual risks of transmission by transfusion did not increase: HIV (1/7,800,000 donations vs. 1/10,500,000), HCV (1/25,200,000 vs. 1/47,300,000) and HBV (1/6,400,000 vs. 1/6,000,000).

CONCLUSION

Reducing the deferral period for MSM in April 2020 did not negatively impact residual risks, which remained very low, or the rate of positive donations, except for syphilis, which requires careful monitoring. To ensure equal access to blood donation, MSM have been allowed to donate blood under the same conditions as other donors since March 2022 (i.e., no more than one sexual partner in the last 4 months).

Acceptability of sexual history questions in a gender-neutral risk assessment for blood donation

BACKGROUND

Currently in Australia, men are deferred from donating blood if they have had sex with another man within the past 3  months. However, a proposed gender-neutral assessment (GNA) process will ask all donors questions about sex with new or multiple recent partners, with deferral based on responses to a question about anal sex. Understanding the acceptability of such questions among existing and potential blood donors is paramount for successful implementation of GNA.

STUDY DESIGN AND METHODS

We used data from a nationally representative survey to estimate the levels of comfort with the proposed GNA questions among the Australian population and subgroups, defined by self-reported ethnicity and religion. Respondents were aged over 18 and living in Australia. Results were weighted to represent the population.

RESULTS

Most of the 5178 respondents described themselves as comfortable with answering questions about new partners (73.1%) or anal sex (64.0%) to donate blood. However, 2.2% and 4.5% indicated that questions about new sex partners and anal sex, respectively, would stop them from donating, and 4.4% and 7.7% respectively, said they were "completely uncomfortable." By religion, the least comfortable were Muslim or Eastern Orthodox respondents, and by country of birth, the least comfortable were those born in the Middle East, followed by those born in Southern Europe and Asia.

DISCUSSION

GNA appears to be broadly acceptable in the Australian context, but our findings suggest that key GNA questions are less acceptable in some population subgroups, indicating a need for targeted campaigns that consider cultural sensitivities.

Blood safety markers in Dutch donors after relaxation of deferral for men who have sex with men: re-emergence of syphilis and HIV pre-exposure prophylaxis use

BACKGROUND

Less discriminatory donor selection policies for men who have sex with men (MSM) may impact transfusion safety in terms of higher residual risks for known transfusion-transmitted infections (TTIs), increased vulnerability toward new TTIs that are also transmitted via sex, and HIV infections masked by pre-exposure prophylaxis (PrEP).

STUDY DESIGN AND METHODS

TTI trends in Dutch donors were studied over a 13-year period (2011-2023), characterized by successive relaxations of MSM deferral criteria. Structured posttest counseling was performed to determine risk factors in TTI-positive donors. PrEP drug levels were measured in 9977 donations from male donors living in urban areas and in 67 donors with active or resolved syphilis.

RESULTS

HIV incidence (from 5.8 to 1.5 per 1,000,000 donor years (DY)) and HBV incidence (from 12.4 to 4.5 per 1,000,000 DY) in Dutch donors decreased with less stringent MSM deferral criteria, while syphilis prevalence (from 26.4 to 44.1 per 100,000 new donors) and syphilis incidence (from 18.3 to 46.3 per 1,000,000 DY) increased over time. The proportion of MSM-related syphilis rose from 2% to 32% in new donors and from 12% to 27% in repeat donors. PrEP was detected in 2 of 9977 (0.02%) donations from male donors living in urban areas, and in 1 of 39 (2.6%) male donors with syphilis.

DISCUSSION

To date, phasing out donor deferral for MSM had no significant impact on transfusion safety in the Netherlands. However, rising syphilis rates and (recent) PrEP use in the blood donor population, albeit rare, suggest an influx of donors with higher sexual risk profiles and requires intensified TTI surveillance in donors.

Implementation of sexual risk behavior donor screening in Canada

BACKGROUND

The two Canadian blood suppliers, Canadian Blood Services and Héma-Québec, removed the time-based deferral for men who have sex with men and adopted criteria assessing sexual risk behaviors. We report the impact of these changes on the safety and adequacy of the Canadian blood supply.

STUDY DESIGN AND METHODS

Since 2022, all donors are asked if (1) they have had a new partner and (2) more than one sexual partner in the last 3 months. Donors answering yes to either question are asked if they had anal sex in the last 3 months; if yes, they are deferred for 3 months. We followed HIV rates for the 18 months before and 14 (Héma-Québec) or 18 months (Canadian Blood Services) post-implementation and interviewed HIV-positive whole blood donors. We assessed the number and characteristics of whole blood donors answering yes to the two first questions with or without deferral.

RESULTS

There were four HIV-positive donations out of 1,492,355 donations pre-implementation and four out of 1,447,772 post-implementation (0.27/100,000 vs. 0.28/100,000, p = 1.00). Post-implementation, one HIV-positive donor was non-compliant with multiple criteria, no risk factors were identified in the others. 3.2% of donors answered yes to questions (1) and/or (2); 0.17% were deferred for a new partner and/or more than one partner and anal sex. Deferral rates were highest in first time, younger donors, and similar in males and females.

CONCLUSION

Implementation of sexual risk behavior donor screening resulted in unchanged HIV rates to date and a manageable deferral rate.

End of selection criteria based on sexual orientation: An international symposium on alternatives to donation deferral

BACKGROUND AND OBJECTIVES

Until recently, gay, bisexual and other men who have sex with men (MSM) were deferred from donating blood for 3-12 months since the last male-to-male sexual contact. This MSM deferral has been discontinued by several high-income countries (HIC) that now perform gender-neutral donor selection.

MATERIALS AND METHODS

An international symposium (held on 20-04-2023) gathered experts from seven HICs to (1) discuss how this paradigm shift might affect the mitigation strategies for transfusion-transmitted infections and (2) address the challenges related to gender-neutral donor selection.

RESULTS

Most countries employed a similar approach for implementing a gender-neutral donor selection policy: key stakeholders were consulted; the transition was bridged by time-limited deferrals; donor compliance was monitored; and questions or remarks on anal sex and the number and/or type of sexual partners were often added. Many countries have now adopted a gender-neutral approach in which questions on pre- and post-exposure prophylaxis for human immunodeficiency virus (HIV) have been added (or retained, when already in place). Other countries used mitigation strategies, such as plasma quarantine or pathogen reduction technologies for plasma and/or platelets.

CONCLUSION

The experience with gender-neutral donor selection has been largely positive among the countries covered herein and seems to be acceptable to stakeholders, donors and staff. The post-implementation surveillance data collected so far appear reassuring with regards to safety, although longer observation periods are necessary. The putative risks associated with HIV antiretrovirals should be further investigated.

The impact of blood donation deferral strategies on the eligibility of men who have sex with men and other sexual risk behavior in Australia

BACKGROUND

In Australia, a man cannot donate blood if he has had sex with another man within the past 3 months. However, this policy has been criticized as being discriminatory as it does not consider lower risk subgroups, and led to calls for modifications to the policy that more accurately distinguish risk among gay, bisexual, and other men who have sex with men (GBM).

STUDY DESIGN AND METHODS

We used data from a nationally representative survey to estimate the proportion of GBM aged 18-74 years old who would be eligible to donate under current criteria and other scenarios.

RESULTS

Among the 5178 survey participants, 155 (3.0%) were classified as GBM based on survey responses, Among the GBM, 40.2% (95% CI 28.0%-53.7%) were eligible to donate based on current criteria, and 21.0% (95% CI 14.5%-29.5%) were ineligible due to the 3 months deferral alone. Eligibility among GBM, all men, and the population increased as criteria were removed. Under the new Australian plasma donation criteria, 73.6% (95% CI 64.4%-81.1%) of GBM, 68.4% (95% CI 65.5%-71.2%) of all men, and 60.8% (95% CI 58.8%-62.8%) of the full population were estimated to be eligible. Only 16.1% (95% CI 8.6%-28.1%) of GBM knew that the male-to-male sex deferral period is 3 months.

DISCUSSION

Changing the deferral criteria and sexual risk evaluation would lead to a higher proportion of GBM being eligible to donate blood. Knowledge of the current GBM deferral period is very low. Improved education about the current criteria and any future changes are required to improve blood donation rates.

MSM and blood donation: shifting to individualized risk assessment

Deferring donors at higher risk for transfusion transmissible infections is an important part of ensuring blood safety. The deferral for gay, bisexual, and other men who have sex with men (gbMSM) was implemented in the 1980s in many countries, since they were identified as a high-risk group for AIDS/HIV. With the introduction of increasingly sensitive HIV antibody testing, augmented by nucleic acid testing, the window period for HIV infection-when a donor may be infectious but have negative test results-has shrunk dramatically. In Canada, this has led to progressively shorter deferral periods for gbMSM, decreasing from a permanent deferral for sex with another male since 1977 to a 5-year, 12-month, and eventually 3-month deferral period. These time-based deferrals maintained safety; however, they are seen as stigmatizing by many and still result in the deferral of sexually active gbMSM. More recently, several countries have moved to a donor screening approach based on assessing sexual risk behaviors in all donors. This article outlines research supporting changes in policy, current eligibility screening policies in several countries, and preliminary results postimplementation of new eligibility policies in Canada in September 2022.

Virological safety of the UK blood supply in the era of individual risk assessments and HIV PrEP

A more individualised donor selection policy was implemented in the UK in 2021, which replaced the previous 3-month deferral for men who have sex with men (MSM). Other blood services have a variety of policies in place to ensure the virological safety of blood components, ranging from an indefinite ban on MSM, to a defined period of exclusion, or to an individualised risk assessment that is not based on gender or sexual orientation. Justification of these policies should be based on scientific evidence including assessment of lengths of virological window periods, infectious disease epidemiology within donor populations and donation screening assay sensitivities. Developments in molecular technology and assays which can detect both antibodies and antigens in the very early stages of infection have significantly reduced the risk in most developed countries. However, the increasing usage of pre-exposure prophylaxis (PrEP) to prevent acquisition of HIV infection after possible high-risk sexual contact within the UK blood donor population has been recently noted. It has brought with it new diagnostic challenges within blood screening, notably possible non-detection of HIV RNA and serological markers following PrEP use despite potential infectivity. The use of other testing strategies such as detection of HIV DNA and screening for non-declared PrEP usage should be investigated further.

Men who have sex with men and risk for transfusion-transmissible infections in blood donors in Western countries: A systematic review update

BACKGROUND AND OBJECTIVES

This systematic review update summarizes evidence concerning transfusion-transmissible infections (TTIs) in male blood donors reporting sex with another man (MSM) or after easing the MSM deferral period.

MATERIALS AND METHODS

We searched five databases, including studies comparing MSM versus non-MSM donors (Type I), MSM deferral periods (Type II) or infected versus non-infected donors (Type III) in Western countries, and used GRADE to determine evidence certainty.

RESULTS

Twenty-five observational studies were included. Four Type I studies suggest that there may be an increased risk for overall TTIs, human immunodeficiency virus (HIV), hepatitis B virus (HBV) and syphilis in MSM donors, but the evidence is very uncertain. There was insufficient evidence of MSM with low-risk sexual behaviour. A Type II study indicates that easing the MSM deferral period to 1 year may have little to no effect on TTI risk. TTI prevalence in blood donors under 5-year, 1-year, 3-month or risk-based deferral in eight other Type II studies was too low to provide clear conclusions on the effect of easing the deferral. Three Type III studies reported that MSM may be a risk factor for HIV. Increased risk of HBV, hepatitis C virus and HTLV-I/II could not be shown. The evidence from Type III studies is very uncertain.

CONCLUSION

There may be an increased risk of HIV in MSM blood donors. Shortening the deferral from permanent to 1 year may have little to no effect on TTI risk. However, there is limited, unclear evidence from observational studies concerning the impact of introducing 3-month or risk-based deferrals.

Evolving the gay, bisexual and other men who have sex with men time-based deferral to sexual risk screening for all donors: The contribution of Canadian research programmes

BACKGROUND AND OBJECTIVES

In Canada, the time deferral for gay, bisexual and other men who have sex with men (gbMSM) to donate blood has gradually decreased. In September 2022, this deferral was replaced with sexual behaviour-based screening for all donors. We investigate how data from targeted research programmes addressed knowledge gaps to support this change.

MATERIALS AND METHODS

We conducted a scoping review describing the Canadian literature available before the research programmes relating to (1) behavioural indicators of HIV risk and (2) attitudes to blood donation among gbMSM, current donors and the general population. We summarize the targeted research programmes, their outputs and impact to date.

RESULTS

For question 1, five projects met inclusion criteria. For question 2, three articles met inclusion criteria. Knowledge gaps identified were insufficient evidence of HIV incidence in gbMSM who met other donor eligibility criteria and scant data on opinions and views of blood donation and screening criteria for sexual risk behaviours. The research programmes funded 19 projects at 11 different research sites involving over 100 individual researchers/collaborators resulting in 19 peer-reviewed publications to date. Leveraging existing gbMSM cohorts yielded relevant HIV incidence data to inform safety modelling studies. Findings indicated that sexual behaviour-based screening was acceptable to gbMSM and donors, and donor discomfort around specific questions could be mitigated with clear explanations.

CONCLUSION

Targeted research programmes filled critical knowledge gaps and informed a change to gender-neutral, sexual behaviour-based screening for all donors. Findings supported successful implementation of these changes with research-informed staff training.

Perceived risk of HIV transmission by blood transfusion among gay, bisexual, and other men who have sex with men (gbMSM) in Australia

BACKGROUND

In Australia, men who have sex with men (MSM) are deferred from blood donation for 3 months from last sexual contact. Internationally, deferral policies for MSM are evolving in the direction of expanded inclusivity in response to community expectations. To inform future policy options, we assessed perceptions of the risk of HIV transmission from blood transfusion among Australian MSM.

STUDY DESIGN AND METHODS

Flux is an online prospective cohort of Australian gay and bisexual men (cis or trans, regardless of their sexual history) and other men who have had sex with men (gbMSM). We included questions on blood donation rules, window period (WP) duration, infectivity of blood from people with HIV on treatment and attitudes to more detailed questioning of sexual practices in the regular survey of Flux participants and conducted a descriptive analysis of responses.

RESULTS

Of 716 Flux participants in 2019, 703 responded to the blood donation questions. The mean age was 43.7 years (SD 13.6 years). Overall, 74% were willing to confidentially respond to specific sexual behavior questions, such as the last time they had sex and the type of sex they had, in order to be considered eligible to donate blood. The majority (92%) of participants correctly assessed the duration of the WP as less than 1 month. When asked whether transfusion of blood from a donor with HIV and an undetectable viral load could transmit HIV, just under half (48%) correctly said yes.

CONCLUSION

Our study suggests Australian gbMSM are generally comfortable with answering more detailed questions regarding sexual activity during the assessment to donate, indicating they would do so honestly. gbMSM are knowledgeable about the WP duration, important for their ability to correctly self-assess their HIV risk. However, half of participants incorrectly assessed the transmissibility by blood transfusion from an HIV positive person with an undetectable viral load, suggesting the need for a targeted education campaign.

Communicating the move to individualized donor selection policy: Framing messages focused on recipients and safety

BACKGROUND

Men-who-have-sex-with-men (MSM) have been deferred from donating blood. However, recent evidence supports the adoption of donor screening based on individuals' sexual behavior over population-based criteria. We explore how best to frame communications about adopting this change to minimize any potential negative consequences (e.g., reduced donor numbers). We examine the effectiveness of risk (emphasizing safety vs. emphasizing low risk), and focus (donor vs. recipient) frames on intentions to donate blood (approach) or feeling deterred from donating (avoid), and mechanisms linked to under-reporting sexual behavior.

STUDY DESIGN AND METHODS

We conducted a 2 (risk frame: risk vs. safety) by 3 (focus: donor vs. recipient vs. both) between-subjects online experiment (n = 2677). The main outcomes were intentions to donate and feelings of being put-off/deterred from donating (both for self and others). We also assessed the extent that forgetting, embarrassment/shame, and question irrelevance were perceived to be associated with under-reporting sexual behavior.

RESULTS

Frames that focused on safety or a recipient resulted in people reporting being less deterred from donating. Regardless of frame, people from ethnic minorities were more likely to feel deterred. Embarrassment/shame followed by forgetting and perceived irrelevance were the main reasons for under-reporting sexual behaviors, especially in ethnic minorities, and smartphones were perceived as an acceptable memory aid for sexual behavior.

DISCUSSION

Blood services moving to an individualized policy should frame donor selection in terms of safety and/or a recipient focus, explore sensitivities in ethnic minority communities, consider ways to normalize reporting sexual behavior, and use smartphones as a memory aid.

Removing the men who have sex with men blood donation deferral: Informing risk models using Canadian public health surveillance data

OBJECTIVE

Gay, bisexual and other men who have sex with men (gbMSM) were ineligible to donate blood in most countries since the 1980's. In Canada the deferral period has been incrementally decreased from lifetime to male-to-male sex in the last 3 months. Now a few countries have removed the deferral altogether. Risk models have been utilised to estimate the probability of an HIV positive donation being released into the blood supply and to inform incremental changes to the length of the deferral period. Here we use public health data to estimate the risk of HIV if the gbMSM deferral criteria were removed in Canada.

MATERIAL AND METHODS

We calculate the risk reduction among heterosexuals based on responses to standard risk questions routinely asked of donors. We assume gbMSM will donate at the same rate as heterosexual males. We apply the same risk reduction principle to HIV incidence and prevalence among gbMSM in the general population to evaluate the HIV risk without gbMSM time deferral. We model three scenarios where risk reduction is varied by assumptions about incidence and compliance with deferral criteria.

RESULTS

The estimates for all scenarios were not significantly different to the currently observed scenario which predicts a residual risk of 0.02 HIV positive per million donations (95% CI: 0.000006-0.09).

CONCLUSION

The models predict that removing the gbMSM deferral criteria would result in HIV residual risk similar to currently observed.

Staff perspectives on barriers and enablers to implementing alternative source plasma eligibility criteria for gay, bisexual, and other men who have sex with men

BACKGROUND

Canadian Blood Services introduced new eligibility criteria that allows some sexually active gay, bisexual, and other men who have sex with men (gbMSM) to donate source plasma, marking a significant change from time-based deferral criteria. We aimed to identify potential barriers and enablers to implementing the new criteria from the perspective of donor center staff.

STUDY DESIGN AND METHODS

We conducted Theoretical Domains Framework-informed interviews with staff from two source plasma donation centers in Canada.

RESULTS

We completed 28 interviews between June 2020 and April 2021. Three themes representing eight domains captured key tensions. Valuing inclusive eligibility criteria: staff support inclusive criteria; many were concerned the new criteria remained discriminatory. Investing in positive donor experiences: staff wished to foster positive donor experiences; however, they worried gbMSM donors would express anger and disappointment regarding the new criteria, staff would experience unease over using stigmatizing criteria and convey nonverbal cues of discomfort, and recurring plasma donors may behave inappropriately. Supporting education, training, and transparency of eligibility criteria: participants believed providing in-person training (i.e., to explain criteria rationale, address discomfort, practice responding to donor questions) and ensuring donors and the public were well-informed of the upcoming changes would improve implementation.

DISCUSSION

Participant views emphasize the importance of supporting staff through training and transparent communication to optimize the delivery of world-class equitable care for a new cohort of donors who have previously been excluded from plasma donation. Findings inform which staff supports to consider to improve implementation as policies continue to shift internationally.

Current advances in transfusion medicine 2021: A critical review of selected topics by the AABB Clinical Transfusion Medicine Committee

BACKGROUND

Each year the AABB Clinical Transfusion Medicine Committee (CTMC) procures a synopsis highlighting new, important, and clinically relevant studies in the field of transfusion medicine (TM). This has been made available as a publication in Transfusion since 2018.

METHODS

CTMC members reviewed and identified original manuscripts covering TM-related topics published electronically (ahead-of-print) or in print from December 2020 to December 2021. Selection of publications was discussed at committee meetings and chosen based on perceived relevance and originality. Next, committee members worked in pairs to create a synopsis of each topic, which was then reviewed by additional committee members. The first and senior authors assembled the final manuscript. Although this synopsis is extensive, it is not exhaustive, and some articles may have been excluded or missed.

RESULTS

The following topics are included: blood products; convalescent plasma; donor collections and testing; hemoglobinopathies; immunohematology and genomics; hemostasis; patient blood management; pediatrics; therapeutic apheresis; and cell therapy.

CONCLUSIONS

This synopsis highlights and summarizes recent key developments in TM and may be useful for educational purposes.