Age patterns of HIV incidence in eastern and southern Africa: a collaborative analysis of observational general population cohort studies
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Background: As the HIV epidemic in sub-Saharan Africa matures, evidence about the age distribution of new HIV infections and how this has changed over the epidemic is needed to guide HIV prevention. We assessed trends in age-specific HIV incidence in six population-based cohort studies in eastern and southern Africa, reporting changes in average age at infection, age distribution of new infections, and birth cohort cumulative incidence. Methods: We used a Bayesian model to reconstruct age-specific HIV incidence from repeated observations of individuals’ HIV serostatus and survival collected among population HIV cohorts in rural Malawi, South Africa, Tanzania, Uganda, and Zimbabwe. The HIV incidence rate by age, time and sex was modelled using smooth splines functions. Incidence trends were estimated separately by sex and study. Estimated incidence and prevalence results for 2000-2017, standardised to study population distribution, were used to estimate average age at infection and proportion of new infections by age. Findings: Age-specific incidence declined at all ages, though the timing and pattern of decline varied by study. The average age at infection was higher in men (cohort means: 27·8-34·6 years) than women (cohort means: 24·8-29·6 years). Between 2000 and 2017, the average age at infection increased slightly: cohort means 0·5-2·8 years among men and -0·2-2·5 years among women. Across studies, between 38-63%(cohort means)of women’s infections were among 15-24-year-olds and between 30-63% of men’s infections were in 20-29-year-olds. Lifetime risk of HIV declined for successive birth cohorts. Interpretation: HIV incidence declined in all age groups and shifted slightly, but not dramatically, to older ages. Disproportionate new HIV infections occur among 15-24-year-old
4women and20-29-year-oldmen, supporting focused prevention in these groups. But 40-60% of infections were outside these ages, emphasising the importance of providing appropriate HIV prevention to adults of all ages.
4women and20-29-year-oldmen, supporting focused prevention in these groups. But 40-60% of infections were outside these ages, emphasising the importance of providing appropriate HIV prevention to adults of all ages.
Date Issued
2021-07
Date Acceptance
2021-03-23
Citation
The Lancet HIV, 2021, 8 (7), pp.e429-e439
ISSN
2405-4704
Publisher
Elsevier
Start Page
e429
End Page
e439
Journal / Book Title
The Lancet HIV
Volume
8
Issue
7
Copyright Statement
© 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0
license.
license.
License URL
Sponsor
Bill & Melinda Gates Foundation
UNAIDS
Medical Research Council (MRC)
Bill & Melinda Gates Foundation
Bill & Melinda Gates Foundation
Wellcome Trust
National Institutes of Health
Identifier
https://www.sciencedirect.com/science/article/pii/S2352301821000692?via%3Dihub
Grant Number
OPP1190661
EPPHZL91/IMPERIAL
MR/R015600/1
2018/837458-0 PO202048522
EPPHZM5513/Imperial
084401/Z/07/Z
1R01MH114562-01
Subjects
11 Medical and Health Sciences
Publication Status
Published
Date Publish Online
2021-06-28