A combination approach – the most impactful mechanism to reduce new HIV cases in Nigeria

Modelling the impact and cost-effectiveness of combination prevention amongst HIV serodiscordant couples in Nigeria.

Mitchell KM, Lepine A, Terris-Prestholt F, Torpey K, Khamofu H, Folayan MO, Musa J, Anenih J, Sagay AS, Alhassan E, Idoko J, Vickerman P. AIDS. 2015 Sep 24;29(15):2035-44. doi: 10.1097/QAD.0000000000000798.

Objective: To estimate the impact and cost-effectiveness of treatment as prevention (TasP), pre-exposure prophylaxis (PrEP) and condom promotion for serodiscordant couples in Nigeria.

Design: Mathematical and cost modelling.

Methods: A deterministic model of HIV-1 transmission within a cohort of serodiscordant couples and to/from external partners was parameterized using data from Nigeria and other African settings. The impact and cost-effectiveness were estimated for condom promotion, PrEP and/or TasP, compared with a baseline where antiretroviral therapy (ART) was offered according to 2010 national guidelines (CD4 <350 cells/µl) to all HIV-positive partners. The impact was additionally compared with a baseline of current ART coverage (35% of those with CD4 <350 cells/µl). Full costs (in US $2012) of programme introduction and implementation were estimated from a provider perspective.

Results: Substantial benefits came from scaling up ART to all HIV-positive partners according to 2010 national guidelines, with additional smaller benefits of providing TasP, PrEP or condom promotion. Compared with a baseline of offering ART to all HIV-positive partners at the 2010 national guidelines, condom promotion was the most cost-effective strategy [US $1206/disability-adjusted-life-year (DALY)], the next most cost-effective intervention was to additionally give TasP to HIV-positive partners (incremental cost-effectiveness ratio US $1607/DALY), followed by additionally giving PrEP to HIV-negative partners until their HIV-positive partners initiate ART (US $7870/DALY). When impact was measured in terms of infections averted, PrEP with condom promotion prevented double the number of infections as condom promotion alone.

Conclusions: The first priority intervention for serodiscordant couples in Nigeria should be scaled up ART access for HIV-positive partners. Subsequent incremental benefits are greatest with condom promotion and TasP, followed by PrEP.

Abstract [1]  Full-text [free] access [2]

Editor’s notes: Despite large reductions in incident HIV infections, Nigeria still has the second largest epidemic globally. Only 35% of  eligible individuals (under NIgerian guidelines) receive antiretroviral treatment. A mathematical model was developed describing HIV-1 transmission between serodiscordant heterosexual partnerships and to/from external partners. The impact and cost-effectiveness of pre-exposure prophylaxis (PrEP), Treatment as Prevention (TasP) and condom promotion for serodiscordant couples was estimated. Two baseline scenarios were used. The first was offering ART at 2010 national guidelines (CD4+<350cells/µl) to all positive individuals. The second assumed current ART coverage (35%) among eligible HIV positive partners.

Scaling up current ART has the greatest impact, and is the most cost effective method for reducing new HIV infections in Nigeria, averting 15% of infections over 20 years. This equated to 35% of all infections under the strategy with the highest impact, which included TasP, long-term PrEP and condom promotion, and 73% of DALYs. The results were most strongly influenced by assumptions around frequency of sex within partnerships, per-act transmission rates, programme efficacy and dropout rates. As more resources become available, after giving ART to all eligible individuals, condom promotion was the next most cost-effective approach. In terms of DALYS averted however, TasP was more likely to be the most cost-effective initial programme.

The study illustrates that the first priority in Nigeria should be scaling up ART to all individuals who are already eligible under Nigerian guidelines from its current level of 35%. Condom promotion within serodiscordant couples was also predicted to be highly cost-effective. Additionally, initiating treatment regardless of CD4 count was predicted to bring about substantial and highly cost-effective additional gains in DALYs averted.

The authors illustrate that combination approaches are important in this setting and should be considered for future programme policy.

condoms [5], treatment [6]
Africa [7]
Nigeria [8]
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