Pre-amble: The promises and pitfalls of using assays for recent

infection to estimate HIV incidence

Denis Nash, PhD, MPH

Associate Professor

Epidemiology and Biostatistics Program

Hunter College School of Public Health

SED Core, HIV Center for Clinical and Behavioral Studies

HIV statusunknown

A prospective study of HIV incidence

Recruitment

A prospective study of HIV incidence

HIV negative

HIVpositive

HIV testingRecruitment

A prospective study of HIV incidence

6 monthsBaseline

HIVpositive

(excluded)

Prospective follow-up

Enrollment of HIV negatives

Prospective follow-upHIV

negative(study

participants)

HIV testingRecruitmentSeroconverted

Did notseroconvert

6 monthsBaseline

HIVpositive

(excluded)

Did notseroconvert

Prospective follow-up

Seroconverted

Person-timeIncidence

rate=

Calculation of HIV incidence

A prospective study of HIV incidence

Enrollment of HIV negatives

Prospective follow-up

HIV testingRecruitment

A cross-sectional study of HIV incidence (STARHS)

HIV statusunknown

Recruitment

6 monthsBaseline Retrospective follow-up

1. Identification of HIV-positive personsvia conventional HIVtesting

A cross-sectional study of HIV incidence (STARHS)

2. Additional testing ofHIV positives by recentInfection assay

Seroconvertedin last 6 months

Seroconverted>6 months ago

6 monthsBaseline Retrospective follow-up

HIV-negative

Seroconvertedin last 6 months

Seroconverted>6 months ago

Person-time

Incidencerate

=

A cross-sectional study of HIV incidence (STARHS)

Calculation of HIV incidence

Excluded

6 monthsBaseline Retrospective follow-up

Person-time

Incidencerate

=

Seroconverted

>6 months ago

(excluded)

Seroconverted

in last 6 months

HIV-negative

Person-time

Baseline 6 months

Incidencerate =

HIVpositive(exclude

d)

Prospective follow-up

Did notseroconver

tSeroconverte

d

Prospective study STARHS (cross-sectional)

Baseline 6 monthsProspectiv

e follow-up