Detecting HIV transmission clusters to better prioritize prevention efforts

Transcription

1 National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention Detecting HIV transmission clusters to better prioritize prevention efforts Alexa Oster, MD Lead (Acting), Transmission and Molecular Epidemiology Team Division of HIV/AIDS Prevention, CDC May 18, 2018

2 Key points The use of molecular surveillance to identify and respond to HIV transmission clusters is a critical step toward bringing the national closer to the goal of no new infections Molecular surveillance tools can analyze HIV genetic material to help understand transmission patterns Molecular surveillance can identify transmission clusters that otherwise would go unrecognized This work offers CDC and state and local HDs the ability to implement targeted prevention activities to stop further transmission

3 Nearly 40,000 people are diagnosed with HIV each year in the U.S. Over 1 million people are living with HIV in the United States

4 Proven prevention methods are available Testing to identify previously undiagnosed infections Ensuring those with diagnosed infections are in care Providing PrEP and other prevention services Focused, community-level interventions But interventions can vary in intensity

5 How do we know where to focus the most intensive prevention efforts?

6 Targeting prevention efforts among people at risk for HIV infection More than 1 million people at risk for HIV infection in the United States Only 38,500 new infections occurred in 2015 How do we know where to focus the most intensive prevention efforts?

7 Focusing prevention efforts for people living with HIV More than 1 million people living with HIV infection in the United States Only 4 transmissions per year per 100 persons living with HIV How do we know where to focus the most intensive prevention efforts?

8 Wouldn t it be nice to have a crystal ball?

9 We don t have a crystal ball, but we do have a useful tool

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11 So how do we identify transmission clusters and outbreaks?

12 Ways to identify transmission clusters Increases in HIV diagnoses in a geographic area or population Particularly useful in areas with low HIV prevalence Could also occur if an increase in HIV testing has diagnosed infections that are longstanding Analysis of HIV sequence data reported to HIV surveillance Particularly useful in identifying transmission clusters that are not detected through other mechanisms, those occurring in an area with a high incidence of HIV infection, those involving multiple jurisdictions HIV partner services and contact investigations Limited by completeness of elicitation of partner information Health care providers, health department staff, or community members

13 Molecular analysis to identify transmission clusters In the United States, HIV drug resistance testing is recommended for all HIV-infected persons Generates HIV nucleotide sequence data (i.e., molecular data) Molecular analysis can detect groups of people with similar HIV strains

14 Why can molecular data be used to detect transmission clusters? HIV mutates/evolves over time People living with HIV infection whose viral strains are genetically similar may be more closely related in transmission LA LA LA LA LA LA LA LA LA LA LA LA RA LA LA LA LA LA LA LA LA RA LA LA LA LA YA LA LA LA RA LA MA LA LA YA LA LA LA LA LA LA LA LA LA LA LA LA LA LA LA LA LA LA LA LA RA LA LA LA LA LA LA LA RA LA MA LA LA YA Analysis: compares nucleotide sequences to determine relatedness ACCGGATAACGGTTATCCG ACCGGATAACGGTTATCCG ACTGGATAACGGTTATCCG ACCGAATCACGGAAATCCG Adapted from presentation by J Gardy

15 Methods: Identifying transmission clusters Secure HIV-TRACE allows state and local HIV surveillance programs to conduct their own molecular analysis Identify pairs of sequences that are very closely related Connect all closely related pairs to identify clusters A B Link drawn between 2 sequences that are closely related Image courtesy of Joel Wertheim, UCSD

16 Molecular epidemiology and HIV Analysis: compares nucleotide sequences to determine relatedness A B A B Person A infected person B Person B infected person A A C B Person A infected person C, who infected person B D A B Persons D infected persons A and B We can infer a direct OR indirect epidemiologic link; we cannot infer directionality

17 Focusing on clusters that represent recent, rapid transmission Very tight genetic distance threshold Priority clusters: At least 5 persons with HIV diagnosed within the recent 12-month period But how do we know that these clusters really represent rapid transmission?

18 HIV transmission in the United States Overall: 4 transmissions per year per 100 people living with HIV

19 HIV transmission rate in priority clusters First 60 priority clusters: 44 transmissions per year per 100 persons living with HIV France AM et al. CROI 2018

20 How are nucleotide sequences collected for National HIV Surveillance System? Persons with HIV Provider orders HIV drug resistance (genotypic) testing Specimen prepared Specimen sent to laboratory Laboratory performs genotypic testing (Sanger) Genetic sequence generated and compared with reference ATGGCATCA ATGTCATCC Resistance report sent to provider Mutations identified and resistance interpreted All of these steps have to happen for a person to be part of a molecular cluster! HIV sequence reported electronically to health department State and local HDs ATGGCATCA

21 Molecular cluster Diagnosed, out of care Infected, not diagnosed At risk, not infected Link to care Test, link to care Test, consider PrEP

22 We still don t have all of the answers Planning a meeting with external partners to discuss several topics: How do we ensure that data are not used for non-public health purposes? How do we share data for public health purposes while ensuring adequate controls? What are best practices for engaging the community around this work? How do we avoid stigmatizing populations who are in need of prevention services? Many other questions remain about the optimal approaches to investigating and responding to HIV transmission clusters Evaluation of these activities will be critical to ensuring that we can determine the most effective approaches to this work

23 : Use of molecular HIV surveillance to identify active HIV transmission networks and implement HIV interventions for Hispanic/Latino MSM Three-year demonstration project (09/ /2020) co-led by PRB and HICSB Funded by Secretary s Minority AIDS Initiative Fund Four recipients: New York City, New York State, Texas, Houston Provides additional funding to grantees to implement activities that expand or enhance PS activities or increase the impact of the HIV-related activities Focuses on Hispanic/Latino MSM and persons in their networks Supports activities to mitigate the negative effects of social-structural factors on participation by these populations in high impact prevention services Supports in-depth analyses and assessments of cluster-related factors and the implementation of high impact HIV prevention services Can improve the reach and effectiveness of HIV-related services among Hispanic/Latino MSM and their network members

24 Efforts in advanced molecular detection are not limited to HIV Global Hepatitis Outbreak and Surveillance Technology (GHOST) is a web-based system that quickly shows genetic linkages between hepatitis C virus

25 Key points The use of molecular surveillance to identify and respond to HIV transmission clusters is a critical step toward bringing the national closer to the goal of no new infections Molecular surveillance tools can analyze HIV genetic material to help understand transmission patterns Molecular surveillance can identify transmission clusters that otherwise would go unrecognized This work offers CDC and state and local HDs the ability to implement targeted prevention activities to stop further transmission

26 Thank you! Alexa Oster, MD For more information, contact CDC CDC-INFO ( ) TTY: The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.