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Volume 6, No. 9, September 2008
Abstract of the Month
Estimation of HIV incidence in the United States
CONTEXT:
Incidence of human immunodeficiency virus (HIV) in the United States has not
been directly measured. New assays that differentiate recent vs long-standing
HIV infections allow improved estimation of HIV incidence.
OBJECTIVE: To estimate HIV incidence in the United States.
DESIGN, SETTING, AND PATIENTS: Remnant diagnostic serum specimens from patients
13 years or older and newly diagnosed with HIV during 2006 in 22 states were
tested with the BED HIV-1 capture enzyme immunoassay to classify infections as
recent or long-standing. Information on HIV cases was reported to the Centers
for Disease Control and Prevention through June 2007. Incidence of HIV in the
22 states during 2006 was estimated using a statistical approach with adjustment
for testing frequency and extrapolated to the United States. Results were corroborated
with back-calculation of HIV incidence for 1977-2006 based on HIV diagnoses from
40 states and AIDS incidence from 50 states and the District of Columbia.
MAIN OUTCOME MEASURE: Estimated HIV incidence.
RESULTS: An estimated 39,400 persons were diagnosed with HIV in 2006 in the 22
states. Of 6864 diagnostic specimens tested using the BED assay, 2133 (31%) were
classified as recent infections. Based on extrapolations from these data, the
estimated number of new infections for the United States in 2006 was 56,300 (95%
confidence interval [CI], 48,200-64,500); the estimated incidence rate was 22.8
per 100,000 population (95% CI, 19.5-26.1). Forty-five percent of infections
were among black individuals and 53% among men who have sex with men. The back-calculation
(n = 1.230 million HIV/AIDS cases reported by the end of 2006) yielded an estimate
of 55,400 (95% CI, 50,000-60,800) new infections per year for 2003-2006 and indicated
that HIV incidence increased in the mid-1990s, then slightly declined after 1999
and has been stable thereafter.
CONCLUSIONS: This study provides the first direct estimates of HIV incidence
in the United States using laboratory technologies previously implemented only
in clinic-based settings. New HIV infections in the United States remain concentrated
among men who have sex with men and among black individuals.
Hall HI, Song R, Rhodes P, Prejean J, An Q, Lee LM, Karon J, Brookmeyer R, Kaplan EH, McKenna MT, Janssen RS; HIV Incidence Surveillance Group. Estimation of HIV incidence in the United States. JAMA. 2008 Aug 6;300(5):520-9. http://www.ncbi.nlm.nih.gov/pubmed/18677024
OB/GYN CCC Editorial comment (Jean E. Howe, MD, MPH):
The above study was undertaken utilizing new technology that allows differentiation of recently acquired HIV infection from longstanding infection. By testing serum from recently diagnosed patients collected in 22 states in 2006, the authors were able to provide a more accurate estimate of the number of newly acquired cases of HIV per year in the United States than had previously been available. Sadly, where the previous estimate of new infections was approximately 40,000 per year in the United States, this study demonstrates that the number of newly acquired cases in 2006 was closer to 56,300 and the incidence rate was 22.8 per 100,000 population. 45% of new cases were in African-Americans and 53% were in men who have sex with men.
This study includes updated estimates of rate of new HIV cases for specific populations:
| Total | 22.8 per 100,000 | ||
| Gender | Race/Ethnicity | ||
| Male | 34.3 per 100,000 | African Amer. | 83.7 per 100,000 |
| Female | 11.9 per 100,000 | Hispanic | 29.3 per 100,000 |
| Age | Amer. Indian/Alaska Native | 14.6 per 100,000 | |
| 13-29 | 26.6 per 100,000 | White | 11.5 per 100,000 |
| 30-39 | 42.6 per 100,000 | Asian/Pac Isl. | 10.3 per 100,000 |
| 40-49 | 30.7 per 100,000 | ||
| 50-99 | 6.5 per 100,000 |
Although the number of HIV/AIDS cases in American Indians and Alaska Natives represents less than 1% of the total number of U.S. cases, when population size is considered, the rate of diagnosis for American Indians and Alaska Natives rank third overall. The CDC has recently updated the “HIV/AIDS among American Indians and Alaska Natives” Fact Sheet. Data presented includes:
- From the beginning of the epidemic through 2005, AIDS was diagnosed in an estimated 3,238 American Indians and Alaska Natives.
- Women accounted for 29% of the HIV/AIDS cases among American Indians & Alaska Natives.
- Transmission categories for American Indian/Alaska Native men were:
61% Male-to-male sexual contact
15% Injection Drug Use
13% Male-to-male sexual contact and injection drug use
10% High-risk heterosexual contact
1%Other
- Transmission categories for American Indian/Alaska Native women were:
68% High-Risk Heterosexual Contact
29% Injection Drug Use
2% Other
The fact sheet also addresses several risk factors that may affect risks for transmission of HIV and barriers to testing for American Indians and Alaska Natives. The full fact sheet can be viewed here: http://www.cdc.gov/hiv/resources/factsheets/PDF/aian.pdf.
As fully one-quarter of Americans of all races with HIV are unaware of their HIV status, and as people aware of their status are less likely to transmit the infection to others, widespread HIV testing is now the national standard of care for adolescents and adults ages 13 to 64 in the United States. The CDC recommends:
For patients in all health-care settings:
- HIV screening is recommended for patients in all health-care settings after the patient is notified that testing will be performed unless the patient declines (opt-out screening).
- Persons at high risk for HIV infection should be screened for HIV at least annually.
- Separate written consent for HIV testing should not be required; general consent for medical care should be considered sufficient to encompass consent for HIV testing.
- Prevention counseling should not be required with HIV diagnostic testing or as part of HIV screening programs in health-care settings.
For pregnant women:
- HIV screening should be included in the routine panel of prenatal screening tests for all pregnant women.
- HIV screening is recommended after the patient is notified that testing will be performed unless the patient declines (opt-out screening).
- Separate written consent for HIV testing should not be required; general consent for medical care should be considered sufficient to encompass consent for HIV testing.
- Repeat screening in the third trimester is recommended in certain jurisdictions with elevated rates of HIV infection among pregnant women.
The full CDC recommendations for HIV screening are available at: http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5514a1.htm
ACOG has now officially endorsed routine screening for women ages 19 to 64 and targeted screening outside of this age group. Simultaneously, ACOG issued a second Committee Opinion emphasizing the increased risk women of color face for acquiring HIV, primarily through heterosexual contact with a partner with undisclosed risk factors. Both Committee Opinions are reviewed here.
Both the CDC and ACOG recommend “opt-out” screening with verbal or written consent. Many states have updated their legal requirements for HIV screening to facilitate opt-out screening with verbal consent. A state-by-state summary of HIV testing laws is now available through the National HIV/AIDS Clinicians’ Consultation Center of the University of California San Francisco and San Francisco General Hospital. The compendium, updated regularly, can be found at: http://www.nccc.ucsf.edu/StateLaws.
Does your worksite routinely offer HIV screening to all adolescents and adults? Is HIV screening routinely included with other prenatal labs unless the pregnant woman declines such testing? A study conducted by the CDC/IHS Epidemiology and Disease Prevention Center in Albuquerque reports that prenatal HIV screening at IHS sites increased from 54% in 2005 to 74% in 2007 but also demonstrated many opportunities to improve both screening and documentation of test results. For more information about this study, please see the report from Brigg Reilley, under “From Your Colleagues” below.
The Indian Health Service has an HIV program which is run by Scott Giberson. He can be reached at Scott.Giberson@ihs.gov.
Centers for Disease Control. CDC HIV/AIDS Fact Sheet; HIV/AIDS among American Indians and Alaska Natives. Updated, August 2008. http://www.cdc.gov/hiv/resources/factsheets/PDF/aian.pd
Centers for Disease Control. MMWR Recommendations and Reports; Revised Recommendations for HIV Testing of Adults, Adolescents, and Pregnant Women in Health-Care Settings. September 22, 2006 / 55(RR14);1-17 http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5514a1.htm
Contents Summary ‹ Previous | Next › From Your Colleagues
OB/GYN
Jean Howe, MD, MPH is the Obstetrics and Gynecology Chief Clinical Consultant (OB/GYN C.C.C.). Dr. Howe is very interested in establishing a dialogue and/or networking with anyone involved in women's health or maternal child health, especially as it applies to American Indian and Alaska Native women and also indigenous peoples around the world. Please don't hesitate to contact her by e-mail (jean.howe@ihs.gov) or phone at (928) 674-7422.
