Models used to predict the impact of having less stringent deferral policies for men who had sex with men: can we validate these predictions?

Changing the deferral for men who have sex with men - an improved model to estimate HIV residual risk

BACKGROUND AND OBJECTIVES

Eight published studies modelled the impact of changing from a lifetime to time-limited deferral for men who have sex with men (MSM); each predicted greater risk impact than has been observed. This study uses these previous efforts to develop an 'optimized' model to inform future changes to MSM deferrals.

MATERIALS AND METHODS

HIV residual risk was calculated using observed HIV incidence/prevalence prior to the change in MSM deferral, then with the additional MSM expected under a 12-month deferral for five compliance scenarios, and finally using data observed after implementation of the deferral. Monte Carlo simulation calculated 95% confidence intervals (CI).

RESULTS

The architecture of reviewed models was sound, and two were selected for combination into the optimized model. HIV risk estimated by this in the UK under MSM lifetime deferral was 0·102 (95% CI: 0·050-0·172) per million. The model predicted from a 27·8% decrease to a 47·6% increase depending upon compliance pre-implementation of the 12-month deferral. A decrease of 0·9% was observed post-implementation. For Canada, HIV risk under a 5-year deferral was 0·050 (95% CI: 0·00003-0·122) per million. Pre-implementation of the 12-month deferral, the model predicted from 30·2% decrease to 10-fold increase. A decrease of 47·0% was observed after implementation.

CONCLUSION

The optimized model predicted HIV risk under 12-month MSM deferral in UK and Canada would remain low, and this was confirmed post-implementation. While the model is adaptable to other deferral scenarios, improved data quality would improve precision, particularly estimates of incidence in individuals likely to donate.

Donor deferral policies for men who have sex with men: where are we today?

PURPOSE OF REVIEW

The review summarizes recent publications on the contentious issue of donor deferral criterion for men who have sex with men (MSM).

RECENT FINDINGS

Recent studies from the United States and China demonstrated that MSM is still a frequent risk factor for HIV-positive donors. Noncompliance is an important factor in the overall risk of HIV transmission but does not appear to be affected by the length of the deferral period. A major US study found a 2.6% noncompliance rate with the current indefinite deferral for MSM; similar or lower rates were found in other jurisdictions with shorter deferral periods. Several countries have had a defined deferral period of 1 year or 5 years in place long enough to determine that increases in HIV-positive cases predicted by modeling studies did not actually occur, suggesting that the assumptions made in these models are overly conservative.

SUMMARY

In summary, MSM eligibility policies are slowly changing around the world, with the US FDA now permitting a 1-year deferral. Transparency, involvement of stakeholders, and careful evaluation of risk and societal benefit should be part of future policy discussions on this issue.

The risk of allowing blood donation from men having sex with men after a temporary deferral: predictions versus reality

BACKGROUND

In most industrialized countries, men who had sex with men (MSM) are permanently deferred from blood donation. Some countries have adopted a temporary deferral after the MSM behavior, thus avoiding donations made during the window period of human immunodeficiency virus (HIV) infection. However, one concern with this approach is the possible increase in the number of HIV-positive donations obtained from unknowingly infected, abstinent MSM; such donations might inadvertently be made available for transfusion, a risk that was previously estimated through mathematical modeling.

STUDY DESIGN AND METHODS

Model predictions were compared to the actual donor rate of HIV in three countries that went from a permanent to a temporary deferral: Australia, the United Kingdom, and Canada.

RESULTS

Depending on the model, a temporary deferral should have increased the rate of HIV in the male donor pool by 73% to more than 3400%. In reality, the very low baseline rate of HIV before the change in these three countries (22 cases/year) remained unchanged 2 years after the revised policy (16 cases/year).

CONCLUSION

These observations strongly suggest that a temporary deferral for MSM incurs zero risk to recipients, at least in jurisdictions where HIV epidemiology is comparable to that of countries where the change happened.

Blood donor deferral for men who have sex with men: the Blood Donation Rules Opinion Study (Blood DROPS)

BACKGROUND

In the United States, any man who discloses having had sex with another man (MSM) even once since 1977 is currently deferred from donating blood. A study was conducted to assess noncompliance with the policy at four geographically dispersed blood centers.

STUDY DESIGN AND METHODS

Male donors 18+ years of age with e-mail addresses were randomly selected and invited to complete a confidential online survey between August and October 2013. No additional recruitment e-mails were sent. Survey content included demographics, sexual history, donation history, compliance with the policy, and opinions about current and modified policies.

RESULTS

Response rate was 11.5% but varied by center (6.3% to 21.7%). Of 3183 completed surveys, 2.6% of respondents (95% confidence interval, 2.1%-3.2%) reported donation after male-male sex. Noncompliance was not statistically different among the centers (p = 0.1), but was related to age with 5.7, 4.6, 2.5, and 1.0% of donors 18 to 24, 25 to 34, 35 to 54, and 50+ years of age, respectively, reporting noncompliance (p < 0.001). Of all respondents, 6.8% reported at least six female and 0.3% reported at least six male sex partners in the past 5 years. Opinions about the current MSM policy were mixed with noncomplying donors more supportive of change than complying donors. Approximatey half of noncompliers indicated they would adhere to a 1-year deferral.

CONCLUSION

Noncompliance with the MSM policy is evident and may be increasing compared to earlier data. Any change from the current policy will require close monitoring to determine whether it affects residual risk of HIV in the US blood supply.