1. Acute HIV Infection: New Strategies for Detection
Pragna Patel MD MPH
Centers for Disease Control and Prevention
Division of HIV/AIDS Prevention
Behavioral and Clinical Surveillance Branch
December 5, 2007

2. Acute HIV Infection
HIV viral replication and shedding occurs before detectable antibody appears
Viremia peaks in blood and genital fluid
Contributes to the spread of HIV because individuals are:
unaware of infection
highly infectious
Important opportunity for HIV prevention
Diagnosis is challenging and requires modification of standard algorithms
Studies have used pooled nucleic acid amplification testing (NAAT) to identify AHI
Yield of screening for acute HIV infection may vary with different enzyme immunoassays (EIA) used to screen for HIV antibody

3. HIV markers during Acute HIV Infection
HIV RNA (plasma)
HIV Antibody 11 10 20 30 40 50 60 70 80 90
100
HIV p24 Ag 16 22
1st generation EIA
2nd generation EIA
Days since infection
3rd generation EIA

4. AHI Study: Primary Objectives
Assess feasibility and cost-effectiveness of pooled NAAT* relative to 3rd generation HIV antibody screening assays and rapid tests
Evaluate effect of pool size on sensitivity and cost-effectiveness of pooled NAAT
Identify HIV infections that would otherwise be missed by current testing
Calculate NAAT sensitivity and specificity
*NAAT = nucleic acid amplification testing for HIV-1 RNA

5. AHI Study: Secondary Objectives
Describe AHI epidemiology & transmission risks
Describe antiretroviral resistance in persons with AHI
Estimate number of transmissions averted through diagnosis & subsequent risk reduction
Describe outcomes of partner notification of persons with AHI
Identify AHI transmission clusters using molecular testing and phylogenetic analyses
Estimate entry into care and treatment outcomes

6. Methods: Study Components
Add NAAT (Aptima®) to routine HIV screening
Component 2:
Study persons with AHI
Baseline and 3 month follow-up surveys
Specimen collection for gene sequencing
Collection of partner counseling and referral services outcomes
Component 3:
Evaluate the performance of NAAT – follow-up EIA-RR and NAAT negative
Specimen collection for further testing
BioRad Genetic System HIV 1/2+O, Abbott, Western blot
Roche Amplicor, Roche DNA PCR, Aptima
Baseline, 3 and 6 month follow-up surveys

7. Methods: Project Areas
Los Angeles Department of Health Services New York State Department of
Health Wadsworth Center, Diagnostic HIV Laboratory
14 sexually transmitted disease clinics and one community center
Vironostika HIV-1 Microelisa System (less sensitive EIA)
Florida Department of Health Florida Bureau of Laboratories
80 public health clinics in 4 counties – Duval, Orange, Hillsborough, Pinellas
BioRad Genetic Systems HIV-1/2 plus O (more sensitive EIA)
New York City Department of Health and Mental Hygiene New York State
Department of Health Wadsworth Center, Diagnostic HIV Laboratory
3 sexually transmitted disease clinics – Fort Greene, Morrisania, Chelsea
Oraquick Advance Rapid HIV 1/2 (oral fluid)
implemented separate consent/counseling for AHI screening

8. Methods: Testing Algorithm
Screening EIA
Negative
Pooled NAAT
Positive
HIV-1 Western Blot
Negative
Indeterminate
or indeterminate
Pool
Negative
HIV negative
Pool
Positive
Individual NAAT
Positive
HIV positive
Individual NAAT
Repeatedly
Negative
Repeatedly
Positive
Check VL
presumptive
AHI
Negative
HIV negative

9. Methods: pooling procedure
1-Stage Pooling
16 Individual Specimens
A B C D E
F G H I J
K L M N O P
1 Master Pool

10. Acute HIV Infection Screening Results May 1, 2006 to October 31, 2007
Population
# tested
HIV Ab+
HIV%
AHI+  HIV case
LA*
30,289
354
1.2 28
8.0%
Florida†
45,288
561 11
2.1%
NYC STD‡
3,624 15
0.4 4
26.7%
* Results using Vironostika HIV-1 Microelisa System
† Results using Bio-Rad Genetic Systems HIV 1/2 + O
‡ Results using Oraquick Advance Rapid HIV 1/2 (oral fluid) – data from June 4, 2007 to October 31, 2007

11. Acute HIV Infection Screening Results May 1, 2006 to October 31, 2007
Test Result
Florida†
Los Angeles*
New York City‡
Presumptive AHIs 11 28 4
EIA-neg/ NAAT-pos 6
EIA-RR/WB-neg/NAAT-pos 2
EIA-RR/WB-ind/NAAT-pos 3
* Results using Vironostika HIV-1 Microelisa System
† Results using Bio-Rad Genetic Systems HIV 1/2 + O
‡ Results using Oraquick Advance Rapid HIV 1/2 (oral fluid) – data from June 4, 2007 to October 31, 2007

12. HIV case detection in LA and NYC using BioRad Genetic Systems 1/2 + O
Tested all acute specimens from LA and NYC using BioRad Genetic Systems 1/2 + O
Los Angeles (n=28)
12 detected and 16 undetected
Yield of AHI screening would decrease from 8.0% to 4.4%
New York City (n=4)
3 detected and 1 undetected
Yield of AHI screening would decrease from 26.7% to 5.5%
Yield of AHI screening higher in LA and NYC compared to FL (2.1%)

13. Epidemiology of Acute HIV Infection
Overall (n=43)
White (40%), Homosexual (48%), Male (95%)
Median age = 30 years old (range 19-56)
Florida (n=11)
African American (64%), Male (82%)
Heterosexual (50%)
Median age = 39 years old (range 19-56)
Los Angeles (n=28)
White (40%) and Hispanic (46%), Male (100%)
Homosexual (54%)
Median age = 29 years (range 18-50)
New York City (n=4)
White (50%) and Hispanic (50%), Male (100%)
Homosexual (75%)
Median age = 26.5 years old (range 23-29)

14. Partner Notification and Testing
Total number of partners named = 50
2 pregnant women
Total number of partners tested = 17
5 tested HIV positive
Both pregnant women tested HIV negative

15. Aptima® Performance Characteristics† Individual Specimens
Florida
Los Angeles
TP = 538
FP = 3
FN = 1
TN = 44696*
TP = 374
FP = 1
FN = 2
TN = 29608*
Sensitivity = 538/539 = 99.81%
Specificity = 44696/44699 = 99.99%
PVP = 538/541 = 99.45%
Sensitivity = 374/376 = 99.47%
Specificity = 29608/29609 = 99.99%
PVP = 374/375 = 99.73%
Given successful validation of pooling scheme, we assume that a negative pool constitutes 16 negative specimens
† Gold Standard = Western blot
‡ TP = true positive, FP = false positive, TN = true negative, FN = false negative

16. Aptima® Performance Characteristics† Pools
Florida
Los Angeles
TP = 5
FP = 0
FN = 0
TN = 2483
TP = 22
FP = 1
FN = 0
TN = 1668
Sensitivity = 5/5 = 100%
Specificity = 2483/2483 = 100%
PVP = 5/5 = 100%
Sensitivity = 22/22 = 100%
Specificity = 1668/1669 = 99.94%
PVP = 22/23 = 95.65%
Given successful validation of pooling scheme, we assume that a negative pool constitutes 16 negative specimens
† Gold Standard = Western blot
‡ TP = true positive, FP = false positive, TN = true negative, FN = false negative

17. Cost Analysis* May 1, 2006 to August 31,2007
Florida†
Los Angeles*
New York City‡
Total program costs
$229,932
$186,509
$25,692
Cost per specimen tested
$5.77
$7.96
$11.35
Cost per AHI (n)
$45,986 (5)
$8,478 (22)
$12,846 (2)
Cost per AHI notified
within 14 days (n)
$114,966 (2)
$18,651 (10)
* Results using Vironostika HIV-1 Microelisa System
† Results using Bio-Rad Genetic Systems HIV 1/2 + O
‡ Results using Oraquick Advance Rapid HIV 1/2 (oral fluid) – data from June 4, 2007 to August 31, 2007
*A. Hutchinson et al. A Micro-costing study of Acute HIV Infection screening
in Florida, Los Angeles and New York City, (Poster # 59)

18. Conclusions
Pooled NAAT in addition to 3rd generation and rapid EIA screening increases HIV case detection
Routine pooling will be most successful with timely notification of results
Aptima® performed well on pooled specimens from routine testing populations
AHI screening using pooled NAAT can be implemented at a cost similar to other HIV screening programs

19. Acknowledgements CDC Duncan Mackellar Patrick Sullivan Steven Ethridge
Steven McDougal
Michele Owen
Walid Heneine
Clyde Hart
Angela Hutchinson
Stephanie Sansom
Paul Farnham
Florida BOL
Berry Bennett
Florida DOH
Marlene LaLota
Pat Simmons
Dan George
Melinda Waters
Dan Pope
Robert Chen
Stacy Shiver
Los Angeles DHS STD
Peter Kerndt
Apurva Uniyal
Ali Stirland
Michael Chen
Stacei Morita
LaShawnda Royal
Kai-Jen Chang
NYS Wadsworth Lab
Monica Parker
Tim Sullivan
Kathy Gombel
NYC DOHMH
Kate Gallagher
Alexis Kowalski
Steven Rubin
Susan Blank

20. Epidemiology of Acute HIV Infection
Characteristics
Florida
n=11
Los Angeles
n=28
New York City
n=4
Total
n=43
Median age (years) 39 29
26.5 30
Gender
Male 82
100 95
Female 18 5
Race (%) *
White 36 40 50
Black 64 14 23
Hispanic 46 35
Sexual Orientation (%)
Bisexual 33
Heterosexual 7 25 19
Homosexual 20 54 75 48
Viral Load >500K 55
Let’s look at the epidemiology of acute HIV infection in this study. Here we have basic characteristics of persons with acute HIV infection. You can see that overall (in the last column) their median age was 30 years old (range, 19-56) and that they were predominately male (95%), white (40%), and homosexual (48%). As you can see, the majority of African Americans, heterosexuals and females with acute HIV were identified in Florida. While in LA and NYC most acute cases were either White or Hispanic men who have sex with men. Interestingly, a number of these men were also bisexual increasing the risk of transmitting HIV to women. Also, half of the persons with AHI had a viral load >500,000 copies/mL (range 8,700 – 6,300,000) at their initial screening.
*‘Other’ race category not represented

21. Summary of false-positive NAAT results, Florida and Los Angeles
Client
Initial Results
Signal to cutoff ratio
Follow-up Results 1
EIA-RR/WB-Neg/NAAT+
VL<75
3.49
(171, 335/49, 008)
EIA-NR/NAAT-
VL not done 2
14.15
(531, 341/37,547)
EIA-RR/WB-Neg/NAAT- 3
EIA-RR/WB-Ind/NAAT+
14.1
(523, 386/37, 181)
10.3
(278, 292/27, 030)
EIA-RR/WB-Ind/NAAT- 4*
EIA-NR/NAAT+
Initial pool = 25.08
Rpt. Pool = 22.43
Individual = 20.85
*pooled and individual testing

22. Summary of false-negative NAAT result, Florida
Initial Results
Signal to cutoff ratio
Follow-up Results
EIA-RR/WB-Ind/NAAT-
0.76
(32,220/44,555)
EIA-RR/WB-pos/NAAT+
7.9
(326,101/41,249)

23. Acute HIV Infection Screening Results May 1, 2006 to October 31, 2007
Test Result
Florida*
Los Angeles†
New York City‡
Total # tested
45,288
30,289
3,624
EIA-neg/NAAT-neg
44,638
29,589
3,597
EIA-RR/WB-pos/NAAT-pos
528
352 15
Presumptive AHIs 11 28 4
EIA-neg/ NAAT-pos 6
EIA-RR/WB-neg/NAAT-pos 2
EIA-RR/WB-ind/NAAT-pos 3
EIA-RR/WB-neg/NAAT-neg 58 19
EIA-RR/WB-ind/NAAT-neg 16 9
EIA-RR/WB-pos/NAAT-neg 33
So, here are our preliminary results…79,201 total tested
Point out categories of presumptive AHIs
1 EIA-RR/WB-ind/NAAT-pos in Florida later tested EIA-RR/WB-ind/NAAT-neg has been reported in HARS as HIV positive previously – therefore, we excluded this person
38 seroconverted – FL 10, LA 22, NYC 4
* Results using BioRad HIV-1/2 plus O
† Results using Vironostika HIV-1 Microelisa System
‡ Results using Oraquick Advance Rapid HIV 1/2 (oral fluid) – data from June 4, 2007 to October 31, 2007

24. Acute HIV Infection Screening Results May 1, 2006 to October 31, 2007
Population
# tested
HIV Ab+
HIV%
AHI+  HIV case
Overall
79,201
930
1.2 43
4.6%
LA*
30,289
354 28
8.0%
Florida†
45,288
561 11
2.1%
NYC STD‡
3,624 15
0.4 4
26.7%
This slide depicts acute HIV infection screening results from May 1, 2006 to October 31, Overall, we tested 79,200 persons, of whom 930 were HIV antibody positive and 43 were acutely infected with HIV. Overall we had a 4.6% increase in HIV case detection. However, we really need to look at the yield of acute HIV screening by project area since each area used a different assay to screen for HIV antibodies. In LA, where Vironostika was used, 30,289 persons were tested, of whom 354 were HIV antibody positive and 28 were acute HIV cases with an 8% increase in HIV case detection. This is very similar to published estimates from California and Seattle. In Florida, where BioRad a 3rd generation HIV antibody test was used to screen for HIV antibody, 45,288 persons were tested of whom 561 were HIV antibody positive and 11 were acute HIV cases with a 2.1% increase in HIV case detection. In NYC, where the project started in June of this year, Oraquick Advance on oral fluid was used to screen for HIV antibody, 3,624 persons were screened of whom 15 were HIV antibody positive and 4 acute HIV cases for a 26.7% increase in HIV case detection. This large increase in case detection is based on a subset of the entire testing population because NYC implemented a separate consent for acute HIV screening. Kate Gallagher will present the differences between the persons who accepted NAAT and those who refused later on in this session. We could have missed persons at risk for AHI due to this opt-in model. Also note, that the HIV prevalence in LA and Florida are similar and in NYC this prevalence does not reflect the prevalence in the total testing population.
Total pop = 8,421; HIV positive =132; 1.6% HIV prevalance
* Results using Vironostika HIV-1 Microelisa System
† Results using Bio-Rad Genetic Systems HIV 1/2 + O
‡ Results using Oraquick Advance Rapid HIV 1/2 (oral fluid) – data from June 4, 2007 to October 31, 2007