hiv and sti department - centre for infections surveillance of recently acquired hiv infections...
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HIV and STI Department - Centre for Infections
Surveillance of recently acquired
HIV infections among newly diagnosed individuals in the
UK
S. Lattimore, G. Murphy, R. Smith, J. Tosswill, D. Pillay, O.N. Gill & V. DelpechOn behalf of the HIV Incidence Advisory and Working Group
Dr Samuel Lattimore
HIV and STI Department - Centre for Infections
Aim of RITA
RITA“Incorporate RITA as part of the routine public health monitoring of all newly
diagnosed HIV infections in England and Wales”
HIV and STI Department - Centre for Infections
The system in EnglandStudy period, 16 months between Feb 2009 to May 2010Estimated 7950 newly diagnosed infections during this time frame, from ~200 laboratories4116 aliquots from diagnostic samples were submitted to the national reference laboratory2480 linked to national epidemiological database (as of 1st July 2010)Representing 2099 individuals
Epidemiologically representative sample
Prevention group Sample received
Est. number of new dx
MSM 886 2834.7
Heterosexual 951 3497.3
IDU 39 145.3
Uncatergorised 223 1473.3
Total 2099 7950.6
HIV and STI Department - Centre for Infections
PerformanceAxSYM avidity - guanidine as chaotrope
Low avidity index (AI) indicates recent infection (<80%)
>90% returned within 5 working days
Results cascaded to the clinic via diagnostic laboratory
HIV and STI Department - Centre for Infections
Reclassification of low avidity specimens
2099 samples, 280 low AI
CD4 <200 within 90 days of dx• Excluded: 20
AIDS diagnosis within 90 days dx• Excluded: 7
HIV positive test result more than 180 days previously• Excluded: 40• 24 seen in the annual census of
individuals accessing HIV treatment and care
• 6 never received treatment• 10 on ARV when sample drawn• 8 ARV reported after sample date
9
301
55
0
1
51 excluded
HIV and STI Department - Centre for Infections
AI 167
Uncategorised: 223IDU: 39Heterosexuals: 951MSM: 889
Individuals: 2099
Duplicate samples: 381
Linked: 2480
Unlinked: 1636
Aliquots received: 4116
Samples not received: ?New dx 7950
LS 888R 63
AI 719 AI 88 AI 863 AI 2 AI 37 AI 22 AI 198
LS 743R 143 LS 38R 1 LS 198R 21
HIV and STI Department - Centre for Infections
Recent infections by prevention group, England Feb 2009 – May 2010
as of end June 2010
Prevention group RecentSamples receive
d
% recent
Population
MSM 143 886 16.1 2834.7
HeterosexualMen 20 322 6.2 1306.6
Women 43 629 6.8 2644.0
IDU 1 39 2.6 145.3
Uncategorised
21 223 9.4 1473.3
HIV and STI Department - Centre for Infections
Similar proportion of recent infections across all age groups
Recent infections among MSM England, Feb 2009 – May 2010
as of end June 2010
0
5
10
15
20
25
30
35
15-24 25-34 35-49 50+
Prop
orti
on r
ecen
t
HIV and STI Department - Centre for Infections
Recent infections among heterosexualsEngland, Feb 2009 – May 2010
as of end June 2010Female:• Highest in
youngest age group
• Antenatal testing
• Decreasing with age
• Peaking again in 50+
Male:• Later peak• Decreasing
with age• Differential
service access
0
5
10
15
20
25
30
35
15-24 25-34 35-49 50+
Prop
orti
on re
cent
Heterosexual male
Heterosexual female
Exact permutation t.test, P = 0.083
HIV and STI Department - Centre for Infections
ConclusionsExperience from England demonstrates national surveillance of recent infections is possible in industrialised countries Application of Laboratory tests for recent information require surveillance informationEstimated costs of 5000 specimens, between 77,000 - £138,000 Among MSM• 1 in 6 recently infected• Similar proportion of recent infections across age groups
Among heterosexuals• 1 in 16 recently infected• Recent infections highest among 15-24 for women, 25-
34 for men• UK acquired
Collect HIV test interval data from clinics to estimate HIV incidence in clinic attendees.
HIV and STI Department - Centre for Infections
www.hpa.org.uk/HIV
Key word STARHS or RITA
HIV and STI Department - Centre for Infections
Acknowledgements
National surveillance teamBrian Rice, Ruth Smith,
Meaghan Kall, Celia Penman, Sonia Ribero, Ragani Raghu
& Vicky Gilbart
National HIV survey teamAlison Brown, Zheng Yin, Tom Hartney, Cuong Chau
National virus reference labGary Murphy, Deenan Pillay, John Parry, Jennifer Tosswill,
Elaine McKinney, Grace Mensah, Caroline Motamed
And a very special thank you to Ruth Smith!
HIV and STI Department - Centre for Infections
SPARE SLIDES
HIV and STI Department - Centre for Infections
Factors independently associated with RHI
after exclusion All Samples: 229 recent
infectionsMale (180; 2.1)Infected in the UK (114; aOR 2.4)White ethnicity (142; aOR 1.8)Born in the UK (93; 2.8)MSM (143; aOR 2.9)MSM: 143 RHI
Infected in the UK (84; aOR 1.4)White ethnicity (113; aOR 2.0)UK born (74; aOR 2.4)No association with age at dx
HET: 63 RHIInfected in the UK (29; aOR 2.7)White ethnicity (21; aOR 1.6)UK born (29; aOR 3.1)Diagnosed in London (40; aOR 3.2)
Age 15-24 (14; aOR 2.2)
HIV and STI Department - Centre for Infections
Proportion of RHI by age group
MSM• No association between
age and RHI• Similar proportion RHI
across age groups
Hets• Highest 15-24,
decreasing to 35-49 (p<0.001)
• More than double the proportion of recent infections among 50+ cf 35-49
MSM Het<25 128 107
25-34 325 36735-49 346 39150+ 87 86
15-24 25-34 35-49 50+0
2
4
6
8
10
12
14
16
18
20
MSM Het
Age group
Pro
port
ion r
ece
nt
22
14
55
26
54
15
12
8
HIV and STI Department - Centre for Infections
Is there a difference by sex among heterosexuals?
Age at dx of recent men
De
nsi
ty0.00
0.01
0.02
0.03
0.04
20 40 60
Age at dx of recent women
De
nsi
ty
0.00
0.01
0.02
0.03
0.04
0 20 40 60 80
Exact permutation t.test, P = 0.083
Women Men
HIV and STI Department - Centre for Infections
Ongoing work
Testing patterns in ageAscertaining country of infectionCombine with UK resistance database to explore subtype issues, and transmitted drug resistanceFalse long-standing infections relies on quantity and quality of surveillance data, especially self-reported testing historyUse RITA as a basis for estimating HIV incidence• Require knowledge of testing bias, representativeness and
population estimates, repeat test pattern
Are we testing the right specimens?• Should AIDS /low CD4 specimens be called misclassified or
should they just be excluded • Are we wrongly increasing the false recent rate by wrongly
including specimens?
HIV and STI Department - Centre for Infections
HIV and STI Department - Centre for Infections
RITA platform
Investigate the maturity of the anti-HIV antibody response by assessing its avidity.Avidity index based upon the rational that avidity increases progressively with time from infection, thus low avidity indicates primary infectionAvidity index applied to other infections including toxoplasmosis, rubella, CMV, HCV, HBV and human herpes virusAI for HIV described by Barbara Suligoi et al 2002Based on an automated AxSYM HIV-1/2gO assay (Abbott)
HIV and STI Department - Centre for Infections
Sensitivity and Specificity
HIV and STI Department - Centre for Infections
Why determine recent HIV infections (RHI)
Monitoring current burden, or prevalence of HIV infection in populations is a blunt tool for understanding:• Trends in transmission• Impact of behaviour change• Impact of public health interventions
Identifying RHI allows us to track patterns in HIV transmission
Reveal groups at greatest risk of HIV infections and• Tailor of health promotion initiatives to meet their needs• Highlight programmes most effective at reducing transmission
May be used to strengthen partner notification programmes, & target discussions on risk behaviour to recent timeframe.
HIV and STI Department - Centre for Infections
CD4 count at diagnosis among laboratory determined recent and long-
standing infectionsCD4 count significantly higher in laboratory determined recent infections (p<0.001)10% RITA recent have CD4 count <200
R LS R LS R LSALL MSM Hets
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
450+350-449200-349<200
Median 529 344 580 400 450 275
R: RecentLS: Long standing
HIV and STI Department - Centre for Infections
Detecting recent HIV infections
CD4 count at diagnosisAIDS diagnosesPrevious positive HIV test
S
T
A
H
R
S
erological
esting
lgorithms
ecent
IV
eroconversion
R
I
T
A
ecent
nfection
esting
lgorithm
SOURCE: Murphy G, Parry JV. Assays for the detection of recent infections with human immunodeficiency virus type 1. Euro.Surveill. 2008;13(36):18966.
HIV and STI Department - Centre for Infections
Factors driving new diagnoses
New HIVDiagnoses
Changes in populationSize (MSM)
Testing
Improvedreporting
Migrationand travel
Transmission(incidence)
HIV and STI Department - Centre for Infections
MSM Het IDU Other/NR0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
20.0
Before Exclusion After ExclusionP
rop
ort
ion
RH
I
MSM Het IDU Other/NR0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
20.0
Before Exclusion After ExclusionP
rop
ort
ion
RH
I
Proportion recent by risk group