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Changing the deferral for men who have sex with men – an improved model to estimate HIV residual risk
Author(s) -
Davison Katy L.,
Gregoire Yves,
Germain Marc,
Custer Brian,
O’Brien Sheila F.,
Steele Whitney R.,
Pillonel Josiane,
Seed Clive R.
Publication year - 2019
Publication title -
vox sanguinis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.68
H-Index - 83
eISSN - 1423-0410
pISSN - 0042-9007
DOI - 10.1111/vox.12826
Subject(s) - deferral , men who have sex with men , residual risk , medicine , demography , incidence (geometry) , human immunodeficiency virus (hiv) , confidence interval , virology , mathematics , economics , geometry , accounting , syphilis , sociology
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.