Net survival of perinatally and postnatally HIV-infected children: a pooled analysis of individual data from sub-Saharan Africa

Abstract

Background: Previously, HIV epidemic models have used a double Weibull curve to represent high initial and late mortality of HIV-infected children, without distinguishing timing of infection (peri- or post-natally). With more data on timing of infection, which may be associated with disease progression, a separate representation of children infected early and late was proposed.

Methods: Paediatric survival post-HIV infection without anti-retroviral treatment was calculated using pooled data from 12 studies with known timing of HIV infection. Children were grouped into perinatally or post-natally infected. Net mortality was calculated using cause-deleted life tables to give survival as if HIV was the only competing cause of death. To extend the curve beyond the available data, children surviving beyond 2.5 years post infection were assumed to have the same survival as young adults. Double Weibull curves were fitted to both extended survival curves to represent survival of children infected perinatally or through breastfeeding.

Results: Those children infected perinatally had a much higher risk of dying than those infected through breastfeeding, even allowing for background mortality. The final-fitted double Weibull curves gave 75% survival at 5 months after infection for perinatally infected, and 1.1 years for post-natally infected children. An estimated 25% of the early infected children would still be alive at 10.6 years compared with 16.9 years for those infected through breastfeeding.

Conclusions: The increase in available data has enabled separation of child mortality patterns by timing of infection allowing improvement and more flexibility in modelling of paediatric HIV infection and survival.

Figures

Figure 1

Survival from time of infection by timing of HIV infection and weighted survival of uninfected children

Figure 2

Survival from time of infection by age at infection for those infected through breastfeeding

Figure 3

Net and gross survival from time since infection for infection perinatally and through breastfeeding

Figure 4

Double Weibull curves fitted to extended net survival functions for early and late HIV infection. Curves were fitted using the net probability of survival of adults age 15–24 years after 2.5 years of follow-up for perinatal infection and 2.0 years for those infected through breastfeeding