PLoS ONE: Estimated HIV Incidence in the United States, 2006–2009

Estimated HIV Incidence in the United States, 2006–2009

The estimated number of new HIV infections in the United States reflects the leading edge of the epidemic. Previously, CDC estimated HIV incidence in the United States in 2006 as 56,300 (95% CI: 48,200–64,500). We updated the 2006 estimate and calculated incidence for 2007–2009 using improved methodology.

We estimated incidence using incidence surveillance data from 16 states and 2 cities and a modification of our previously described stratified extrapolation method based on a sample survey approach with multiple imputation, stratification, and extrapolation to account for missing data and heterogeneity of HIV testing behavior among population groups.

Estimated HIV incidence among persons aged 13 years and older was 48,600 (95% CI: 42,400–54,700) in 2006, 56,000 (95% CI: 49,100–62,900) in 2007, 47,800 (95% CI: 41,800–53,800) in 2008 and 48,100 (95% CI: 42,200–54,000) in 2009. From 2006 to 2009 incidence did not change significantly overall or among specific race/ethnicity or risk groups. However, there was a 21% (95% CI:1.9%–39.8%; p = 0.017) increase in incidence for people aged 13–29 years, driven by a 34% (95% CI: 8.4%–60.4%) increase in young men who have sex with men (MSM). There was a 48% increase among young black/African American MSM (12.3%–83.0%; p<0.001). Among people aged 13–29, only MSM experienced significant increases in incidence, and among 13–29 year-old MSM, incidence increased significantly among young, black/African American MSM. In 2009, MSM accounted for 61% of new infections, heterosexual contact 27%, injection drug use (IDU) 9%, and MSM/IDU 3%.

Overall, HIV incidence in the United States was relatively stable 2006–2009; however, among young MSM, particularly black/African American MSM, incidence increased. HIV continues to be a major public health burden, disproportionately affecting several populations in the United States, especially MSM and racial and ethnic minorities. Expanded, improved, and targeted prevention is necessary to reduce HIV incidence.

Joseph Prejean1*, Ruiguang Song1, Angela Hernandez1, Rebecca Ziebell2, Timothy Green1, Frances Walker1, Lillian S. Lin1, Qian An1, Jonathan Mermin1, Amy Lansky1, H. Irene Hall1, for the HIV Incidence Surveillance Group¶

1 Division of HIV/AIDS Prevention, National Center for HIV, Viral Hepatitis, STD and TB Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America, 2 The Ginn Group, Peachtree City, Georgia, United States of America

Abstract
Background
The estimated number of new HIV infections in the United States reflects the leading edge of the epidemic. Previously, CDC estimated HIV incidence in the United States in 2006 as 56,300 (95% CI: 48,200–64,500). We updated the 2006 estimate and calculated incidence for 2007–2009 using improved methodology.

Methodology
We estimated incidence using incidence surveillance data from 16 states and 2 cities and a modification of our previously described stratified extrapolation method based on a sample survey approach with multiple imputation, stratification, and extrapolation to account for missing data and heterogeneity of HIV testing behavior among population groups.

Principal Findings
Estimated HIV incidence among persons aged 13 years and older was 48,600 (95% CI: 42,400–54,700) in 2006, 56,000 (95% CI: 49,100–62,900) in 2007, 47,800 (95% CI: 41,800–53,800) in 2008 and 48,100 (95% CI: 42,200–54,000) in 2009. From 2006 to 2009 incidence did not change significantly overall or among specific race/ethnicity or risk groups. However, there was a 21% (95% CI:1.9%–39.8%; p = 0.017) increase in incidence for people aged 13–29 years, driven by a 34% (95% CI: 8.4%–60.4%) increase in young men who have sex with men (MSM). There was a 48% increase among young black/African American MSM (12.3%–83.0%; p<0.001). Among people aged 13–29, only MSM experienced significant increases in incidence, and among 13–29 year-old MSM, incidence increased significantly among young, black/African American MSM. In 2009, MSM accounted for 61% of new infections, heterosexual contact 27%, injection drug use (IDU) 9%, and MSM/IDU 3%.

Conclusions/Significance
Overall, HIV incidence in the United States was relatively stable 2006–2009; however, among young MSM, particularly black/African American MSM, incidence increased. HIV continues to be a major public health burden, disproportionately affecting several populations in the United States, especially MSM and racial and ethnic minorities. Expanded, improved, and targeted prevention is necessary to reduce HIV incidence.

Citation: Prejean J, Song R, Hernandez A, Ziebell R, Green T, et al. (2011) Estimated HIV Incidence in the United States, 2006–2009. PLoS ONE 6(8): e17502. doi:10.1371/journal.pone.0017502

Editor: Vernon Lee, National University of Singapore, Singapore


Received: September 24, 2010; Accepted: June 30, 2011; Published: August 3, 2011

This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.

Funding: The Centers for Disease Control and Prevention (CDC) provides funding to state and local health departments to conduct surveillance of HIV disease in accordance with their own disease reporting regulations. CDC provides technical guidance for the collection of data by the state and local health departments and data are sent to CDC for national-level analyses. The analysis methods for this manuscript were developed by CDC. CDC makes all decisions regarding the publication of national surveillance data as a means to describe the HIV epidemic. The Ginn Group, Peachtree City, Georgia, United States of America, a sub-contractor of the Northrop Grumman Corporation, employs Rebecca Ziebell and provided scientific analysis services as directed by CDC through a contract with CDC.

Competing interests: Rebecca Ziebell is an employee of The Ginn Group, Peachtree City, Georgia, United States of America, a sub-contractor of the Northrop Grumman Corporation which provides scientific analysis services under contract to and as directed by the Centers for Disease Control and Prevention (CDC). This affiliation does not alter the authors' adherence to all the PLoS ONE policies on sharing data and materials.

* E-mail: nzp1@cdc.gov
¶ Membership of the HIV Incidence Surveillance Group is provided in the Acknowledgments.

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PLoS ONE: Estimated HIV Incidence in the United States, 2006–2009