Dataset Information

The role of acute and early HIV infection in the spread of HIV and implications for transmission prevention strategies in Lilongwe, Malawi: a modelling study.

ABSTRACT:

Background

HIV transmission risk is higher during acute and early HIV infection than it is during chronic infection, but the contribution of early infection to the spread of HIV is controversial. We estimated the contribution of early infection to HIV incidence in Lilongwe, Malawi, and predict the future effect of hypothetical prevention interventions targeted at early infection only, chronic infection only, or both stages.

Methods

We developed a deterministic mathematical model describing heterosexual HIV transmission, informed by detailed behavioural and viral-load data collected in Lilongwe. We included sexual contact within and outside of steady pairs and divided the infectious period into intervals to allow for changes in transmissibility by infection stage. We used a Bayesian melding approach to fit the model to HIV prevalence data collected between 1987 and 2005 at Lilongwe antenatal clinics. We assessed interventions that reduced the per-contact transmission probability to 0.00003 in people receiving them, and varied the proportion of individuals receiving the intervention in each stage.

Findings

We estimated that 38.4% (95% credible interval 18.6-52.3) of HIV transmissions in Lilongwe are attributable to sexual contact with individuals with early infection. Interventions targeted at only early infection substantially reduced HIV prevalence, but did not lead to elimination, even with 100% coverage. Interventions targeted at only chronic infections also reduced HIV prevalence, but coverage levels of 95-99% were needed for the elimination of HIV. In scenarios with less than 95% coverage of interventions targeted at chronic infections, additional interventions reaching 25-75% of individuals with early infection reduced HIV prevalence substantially.

Interpretation

Our results suggest that early infection plays an important part in HIV transmission in this sub-Saharan African setting. Without near-complete coverage, interventions during chronic infection will probably have incomplete effectiveness unless complemented by strategies targeting individuals with early HIV infection.

Funding

National Institutes of Health, University of North Carolina Center for AIDS Research.

SUBMITTER: Powers KA

PROVIDER: S-EPMC3274419 | biostudies-literature | 2011 Jul

REPOSITORIES: biostudies-literature

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Publications

The role of acute and early HIV infection in the spread of HIV and implications for transmission prevention strategies in Lilongwe, Malawi: a modelling study.

Powers Kimberly A KA Ghani Azra C AC Miller William C WC Hoffman Irving F IF Pettifor Audrey E AE Kamanga Gift G Martinson Francis Ea FE Cohen Myron S MS

Lancet (London, England) 20110701 9787

<h4>Background</h4>HIV transmission risk is higher during acute and early HIV infection than it is during chronic infection, but the contribution of early infection to the spread of HIV is controversial. We estimated the contribution of early infection to HIV incidence in Lilongwe, Malawi, and predict the future effect of hypothetical prevention interventions targeted at early infection only, chronic infection only, or both stages.<h4>Methods</h4>We developed a deterministic mathematical model d ...[more]

PMID: 21684591

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Project description:BackgroundCOVID-19 mitigation strategies have been challenging to implement in resource-limited settings due to the potential for widespread disruption to social and economic well-being. Here we predict the clinical severity of COVID-19 in Malawi, quantifying the potential impact of intervention strategies and increases in health system capacity.MethodsThe infection fatality ratios (IFR) were predicted by adjusting reported IFR for China, accounting for demography, the current prevalence of comorbidities and health system capacity. These estimates were input into an age-structured deterministic model, which simulated the epidemic trajectory with non-pharmaceutical interventions and increases in health system capacity.FindingsThe predicted population-level IFR in Malawi, adjusted for age and comorbidity prevalence, is lower than that estimated for China (0.26%, 95% uncertainty interval (UI) 0.12%-0.69%, compared with 0.60%, 95% CI 0.4% to 1.3% in China); however, the health system constraints increase the predicted IFR to 0.83%, 95% UI 0.49%-1.39%. The interventions implemented in January 2021 could potentially avert 54 400 deaths (95% UI 26 900-97 300) over the course of the epidemic compared with an unmitigated outbreak. Enhanced shielding of people aged ≥60 years could avert 40 200 further deaths (95% UI 25 300-69 700) and halve intensive care unit admissions at the peak of the outbreak. A novel therapeutic agent which reduces mortality by 0.65 and 0.8 for severe and critical cases, respectively, in combination with increasing hospital capacity, could reduce projected mortality to 2.5 deaths per 1000 population (95% UI 1.9-3.6).ConclusionWe find the interventions currently used in Malawi are unlikely to effectively prevent SARS-CoV-2 transmission but will have a significant impact on mortality. Increases in health system capacity and the introduction of novel therapeutics are likely to further reduce the projected numbers of deaths.

Dataset Information

The role of acute and early HIV infection in the spread of HIV and implications for transmission prevention strategies in Lilongwe, Malawi: a modelling study.

Background

Methods

Findings

Interpretation

Funding

Publications

The role of acute and early HIV infection in the spread of HIV and implications for transmission prevention strategies in Lilongwe, Malawi: a modelling study.

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