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HIV Infections Attributed to Male-to-Male Sexual Contact — Metropolitan Statistical Areas, United States and Puerto Rico, 2010

Human immunodeficiency virus (HIV) infections attributed to male-to-male sexual contact comprised 64% of the estimated new HIV infections in the United States in 2009 (1). Assessing the geographic distribution of HIV infection by transmission category can help public health programs target prevention resources to men who have sex with men (MSM) in areas where HIV infection from male-to-male sexual contact is most frequent. In 2004, CDC published data on acquired immunodeficiency syndrome diagnoses among MSM and others by metropolitan statistical area (MSA) (2). To examine geographic differences in the prevalence of HIV infection from male-to-male sexual contact among persons aged ≥13 years in the United States and Puerto Rico, CDC estimated the number of HIV infections in persons newly diagnosed in 2010 and analyzed them by transmission category and location. Results indicated that HIV infections attributed to male-to-male sexual contact made up the largest percentage of HIV infections in MSAs (62.1%), smaller metropolitan areas (56.1%), and nonmetropolitan areas (53.7%). Of the 28,851 infections attributed to male-to-male sexual contact, 23,559 (81.7%) were in MSAs, and 11,410 (48.4%) of those infections were in seven MSAs that represented 31.7% (53,169,004 of 167,919,694) of the overall population aged ≥13 years in the MSAs that were assessed. These data support planning for targeted interventions to prevent HIV acquisition and transmission by male-to-male sexual contact among MSM, particularly in those areas most affected.

HIV infections in persons newly diagnosed in 2010 that were reported to the National HIV Surveillance System through June 2011 were examined from 564 locations, including 103 MSAs, 263 smaller metropolitan areas, and 198 nonmetropolitan areas in the United States and Puerto Rico.* Reported diagnoses of HIV infection for persons aged ≥13 years were tallied, and numbers of diagnoses overall and by transmission category were estimated. Data were adjusted for reporting delays and missing HIV risk factors but not for underreporting (3,4). Because a substantial proportion of persons with diagnosed HIV infection are reported to CDC without an identified risk factor, multiple imputation methods are used to assign transmission categories to those persons whose diagnoses are reported without a risk factor (4). Multiple imputation is a statistical approach in which missing transmission categories for each person are replaced with plausible values that represent the uncertainty regarding the actual, but missing, values (5).

Estimates were calculated for new diagnoses of HIV infection attributed to male-to-male sexual contact, injection-drug use, male-to-male sexual contact and injection-drug use, heterosexual contact, and other HIV risk factors or modes of transmission (e.g., hemophilia, blood transfusion, or perinatal exposure). Transmission categories are assigned, based on the single risk factor (of all identified risk factors) that was most likely responsible for HIV transmission (6,7). An exception is male-to-male sexual contact and injection-drug use, which makes up a separate transmission category. Estimates were not calculated for locations that did not have confidential name-based HIV reporting in place by January 2007 (or had not reported these data to CDC since at least June 2007) to enable the calculation of reporting delays. Excluded were locations in Hawaii, Maryland, Massachusetts, Vermont, and the District of Columbia (6).

Of the estimated 37,934 persons aged ≥13 years with a diagnosis of HIV infection who resided in MSAs in the United States and Puerto Rico during 2010, a total of 23,559 (62.1%) had HIV infection attributed to male-to-male sexual contact; 10,128 (26.7%) had HIV infection attributed to heterosexual contact, 3,070 (8.1%) to injection-drug use, 1,145 (3.0%) to male-to-male sexual contact and injection-drug use, and 33 (0.1%) to other modes of transmission (Table 1). Among smaller metropolitan areas, 3,182 (56.1%) of 5,677 HIV infections were attributed to male-to-male sexual contact, and among nonmetropolitan areas, 1,756 (53.7%) of 3,272 HIV infections were attributed to male-to-male sexual contact (Table 1). Of the 28,851 HIV infections among persons with infection attributed to male-to-male sexual contact overall, 23,559 (81.7%) were among persons living in MSAs. Persons aged ≥13 years living in MSAs comprised 65.5% (167,919,694 of 256,388,562) of the total population† of persons aged ≥13 years for the areas that were assessed (103 MSAs, 263 smaller metropolitan areas, and 198 nonmetropolitan areas).

A total of 11,410 (48.4%) of the 23,559 estimated HIV infections attributed to male-to-male sexual contact were among persons who resided in seven MSAs: New York, New York, New Jersey, Pennsylvania (3,347); Los Angeles, California (2,589); Miami, Florida (1,481); Atlanta-Sandy Springs-Marietta, Georgia (1,059); Chicago, Illinois, Indiana, Wisconsin (1,011); Dallas, Texas (995), and Houston-Baytown-Sugar Land, Texas (928) (Table 2). Persons aged ≥13 years residing in these seven MSAs comprised 31.7% (53,169,004 of 167,919,694) of the total population of persons aged ≥13 years for the MSAs that were assessed. The four largest percentages of HIV infections attributed to male-to-male sexual contact in MSAs were in Los Angeles, California (81.9%), Fresno, California (80.8%), Modesto, California (78.8%), and Oxnard-Thousand Oaks-Ventura, California (78.2%).§

Reported by

Hollie Clark, MPH, H. Irene Hall, PhD, Tian Tang, MS, Shericka Harris, MPH, Anna Satcher Johnson, MPH, Joseph Prejean, PhD, Div of HIV/AIDS Prevention, National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, CDC. Corresponding contributor: Hollie Clark, hclark@cdc.gov, 404-639-3983.

Editorial Note

The results of this analysis indicate that the majority of HIV infections in newly diagnosed persons aged ≥13 years in 2010 were attributed to male-to-male sexual contact. The percentages of HIV infections attributable to male-to-male sexual contact were higher in MSAs, compared with smaller metropolitan areas and nonmetropolitan areas. Among the MSAs examined, seven accounted for 48.4% of the persons with HIV infection attributable to male-to-male sexual contact. The four MSAs with the largest percentages of HIV infections attributed to male-to-male sexual contact were located in California. These results highlight the disproportionate burden of HIV infection among MSM, who were estimated to comprise approximately 3.9% of the male population aged ≥13 years in 2008 in the United States (8).

The geographic concentration of HIV infection reflects the higher risk for HIV transmission in areas with larger populations, greater prevalence of HIV infection attributed to male-to-male contact (e.g., MSAs compared with smaller areas), and possibly a greater prevalence of MSM living in the community. Effective interventions that could reduce the number of HIV infections in MSAs include HIV testing, HIV care and treatment, and risk-reduction counseling.

The findings in this report are subject to at least three limitations. First, HIV infection surveillance locations in five areas were excluded because they had not had confidential name-based reporting in place by January 2007 or had not reported these data to CDC since at least June 2007. The effect of this limitation is unknown. Second, comparisons were made based on estimated percentages of diagnoses instead of HIV diagnosis rates. To evaluate disparities in HIV risk between groups, HIV diagnosis rates should be calculated by applying population denominators for persons within each transmission category; however, such population estimates currently are unavailable for MSAs, smaller metropolitan areas, and nonmetropolitan areas. Finally, transmission category estimates were adjusted for missing risk factor information. Whether these adjustments introduce any bias in overestimation or underestimation of percentages of HIV infection attributed to specific categories is unknown. Adjusted estimates should be interpreted with caution, particularly when numbers are small (i.e., less than 12).

CDC's High-Impact HIV Prevention¶ program relies on geographic targeting of resources and proven, cost-effective interventions to achieve the goals of the National HIV/AIDS Strategy, which include reducing the number of persons who become infected with HIV, increasing access to care and optimizing health outcomes for persons living with HIV, and reducing HIV-related health disparities.** The results of this analysis underscore the uneven geographic distribution of the burden of HIV infection in MSAs in the United States and Puerto Rico. The geographic disparity in HIV burden also indicates a need to target MSM who bear a large percentage of the burden of infection in areas where persons are at greatest risk for HIV transmission. Health departments, community-based organizations, and other agencies can use these results in planning interventions in their areas to reduce HIV infection and transmission.

References

Prejean J, Song R, Hernandez A, et al. Estimated HIV incidence in the United States, 2006–2009. PLoS One 2011;6:e17502.
CDC. AIDS cases, by geographic area of residence and metropolitan statistical area of residence, 2004. HIV/AIDS surveillance supplemental report. Vol. 12, No. 2. Atlanta, GA: US Department of Health and Human Services, CDC; 2006. Available at http://www.cy118119.com/hiv/surveillance/resources/reports/2006supp_vol12no2/pdf/cover.pdf. Accessed November 21, 2012.
Song R, Green TA. An improved approach to accounting for reporting delay in case surveillance systems. JP Journal of Biostatistics 2012;7:1–14.
Harrison KM, Kajese T, Hall HI, Song R. Risk factor redistribution of the national HIV/AIDS surveillance data: an alternative approach. Public Health Rep 2008;123:618–27.
Rubin, DB. Multiple imputation for nonresponse in surveys. New York, NY: John Wiley & Sons, Inc.; 1987.
CDC. Diagnoses of HIV infection and AIDS in the United States and dependent areas, 2010. HIV surveillance report, 2010. Vol. 22. Atlanta, GA: US Department of Health and Human Services, CDC; 2012. Available at http://www.cy118119.com/hiv/surveillance/resources/reports/2010report/index.htm. Accessed November 21, 2012.
CDC. Terms, definitions, and calculations used in CDC HIV surveillance publications. Atlanta, GA: US Department of Health and Human Services, CDC; 2012. Available at http://www.cy118119.com/hiv/topics/surveillance/resources/factsheets/pdf/surveillance_terms_definitions.pdf. Accessed November 21, 2012.
Purcell DW, Johnson CH, Lansky A, et al. Estimating the population size of men who have sex with men in the United States to obtain HIV and syphilis rates. Open AIDS J 2012;6:98–107.

* MSAs have populations ≥500,000; smaller metropolitan areas have populations of 50,000–499,999, and nonmetropolitan areas are those with populations <50,000. Additional information available at http://www.whitehouse.gov/sites/default/files/omb/assets/bulletins/b10-02.pdf.

† Includes populations for adults and adolescents living in seven MSAs that were excluded from the total estimated number of HIV infections attributed to male-to-male contact.

§ Only percentages based on estimated numbers ≥12 are presented.

¶ Additional information available at http://www.cy118119.com/hiv/strategy/hihp/pdf/dhap_policy_maker.pdf.

** Additional information available at http://www.whitehouse.gov/administration/eop/onap/nhas.

What is already known on this topic?

In 2009, an estimated 64% of new human immunodeficiency virus (HIV) infections were attributed to male-to-male sexual contact.

What is added by this report?

Of the estimated 28,851 infections in 2010 attributed to male-to-male sexual contact, 23,559 (81.7%) were in metropolitan statistical areas (MSAs) with populations of 500,000 or more in the United States and Puerto Rico, and 11,410 (48.4%) of those infections were in seven of the MSAs assessed. The four MSAs with the greatest percentages of HIV infections attributed to male-to-male sexual contact were in California.

What are the implications for public health practice?

Effective interventions that could reduce the number of HIV infections in areas where men who have sex with men are at greater risk for HIV infection and transmission by male-to-male contact include HIV testing, HIV care and treatment, and risk-reduction counseling.

*TABLE 1. Estimated number and percentage of diagnoses of HIV infection† among persons aged ≥13 years, by transmission category and size of location of residence — National HIV Surveillance System, United States and Puerto Rico, 2010**
Location of residence (population)	HIV transmission category															Total diagnoses
	Male-to-male sexual contact			Injection-drug use			Male-to-male sexual contact and injection-drug use			Heterosexual contact			Other transmission§			Total diagnoses
	Reported no.¶	Estimated no.**	% of total	Reported no.¶	Estimated no.**	% of total	Reported no.¶	Estimated no.**	% of total	Reported no.¶	Estimated no.**	% of total	Reported no.¶	Estimated no.**	% of total	Reported no.¶	Estimated no.**
MSAs (≥500,000)	16,898	23,559	62.1	1,522	3,070	8.1	800	1,145	3.0	5,343	10,128	26.7	10,637	33	0.1	35,200	37,934
Small metropolitan areas (50,000–499,999)	2,153	3,182	56.1	248	502	8.8	114	182	3.2	840	1,802	31.7	1,525	8	0.1	4,880	5,677
Nonmetropolitan areas (<50,000)	1,137	1,756	53.7	161	313	9.6	69	121	3.7	491	1,076	32.9	1,033	5	0.2	2,891	3,272
Total	20,332	28,851	60.8	1,963	3,963	8.3	986	1,463	3.1	6,716	13,153	27.7	13,381	46	0.1	43,378	47,477
Abbreviations: HIV = human immunodeficiency virus; MSAs = metropolitan statistical areas. * Estimates result from statistical adjustment that accounted for reporting delays, but not for incomplete reporting. Cases without reported risk factors were assigned transmission categories using multiple imputation methods. † Includes all new diagnoses of HIV infection, regardless of stage of disease at diagnosis. § Includes hemophilia, blood transfusion, and perinatal exposure. ¶ Includes reported numbers from 103 MSAs, 263 smaller metropolitan areas, and 198 nonmetropolitan areas. ** Includes estimated numbers only from 96 MSAs, 258 smaller metropolitan areas, and 198 nonmetropolitan areas located in areas that had implemented confidential name-based HIV infection reporting by at least January 2007 and had reported these data to CDC since at least June 2007. Reported and estimated numbers smaller than 12 or percentages based on estimated numbers smaller than 12 are considered unreliable and should be interpreted with caution.

*TABLE 2. Estimated number and percentage of diagnoses of HIV infection† attributed to male-to-male sexual contact among persons aged ≥13 years, by location of residence — National HIV Surveillance System, United States and Puerto Rico, 2010**
Location of residence	HIV infection attributed to male-to-male sexual contact			Total diagnoses
Location of residence	Reported no.§	Estimated no.¶	% of total	Reported no.§	Estimated no.¶
Akron, Ohio	13	21	60.2	33	35
Albany–Schenectady–Troy, New York	28	46	46.4	75	99
Albuquerque, New Mexico	43	57	75.0	70	76
Allentown–Bethlehem–Easton, Pennsylvania, New Jersey	25	35	49.7	63	70
Atlanta–Sandy Springs–Marietta, Georgia	387	1,059	64.5	1,182	1,641
Augusta–Richmond County, Georgia, South Carolina	24	67	52.4	89	128
Austin–Round Rock, Texas	144	186	71.1	239	262
Bakersfield, California	28	50	36.0	112	138
Baltimore–Towson, Maryland	96	—	—	818	—
Baton Rouge, Louisiana	88	146	43.2	312	337
Birmingham–Hoover, Alabama	91	145	60.9	217	238
Boise City–Nampa, Idaho	9	17	60.8	25	27
Boston–Cambridge–Quincy, Massachusetts, New Hampshire	156	—	—	431	—
Bradenton–Sarasota–Venice, Florida	44	55	59.1	85	92
Bridgeport–Stamford–Norwalk, Connecticut	33	55	38.5	107	142
Buffalo–Niagara Falls, New York	51	77	45.8	127	169
Cape Coral–Fort Myers, Florida	28	33	34.1	89	97
Charleston–North Charleston, South Carolina	67	85	63.5	123	134
Charlotte–Gastonia–Concord, North Carolina, South Carolina	204	292	63.7	408	459
Chattanooga, Tennessee, Georgia	19	36	55.1	55	65
Chicago, Illinois, Indiana, Wisconsin	604	1,011	68.9	1205	1,468
Cincinnati–Middletown, Ohio, Kentucky, Indiana	113	164	66.7	226	246
Cleveland–Elyria–Mentor, Ohio	104	169	73.4	213	230
Colorado Springs, Colorado	21	28	72.2	35	38
Columbia, South Carolina	104	142	62.5	209	228
Columbus, Ohio	159	258	75.8	316	340
Dallas, Texas	767	995	68.4	1,334	1,455
Dayton, Ohio	62	75	76.2	90	98
Denver–Aurora, Colorado	201	241	68.2	322	353
Des Moines, Iowa	21	29	68.1	39	43
Detroit, Michigan	244	367	67.6	508	544
Durham–Chapel Hill, North Carolina	41	60	50.3	109	119
El Paso, Texas	77	101	76.1	121	132
Fresno, California	75	94	80.8	97	117
Grand Rapids–Wyoming, Michigan	21	29	69.5	39	42
Greensboro–High Point, North Carolina	66	87	62.6	128	139
Greenville, South Carolina	38	47	64.7	67	73
Harrisburg–Carlisle, Pennsylvania	22	31	54.3	53	57
Hartford–West Hartford–East Hartford, Connecticut	67	98	47.1	164	207
Honolulu, Hawaii	32	—	—	61	—
Houston–Baytown–Sugar Land, Texas	616	928	59.7	1,425	1,553
Indianapolis, Indiana	131	177	65.4	247	270
Jackson, Mississippi	62	104	56.7	167	184
Jacksonville, Florida	154	175	45.2	355	388
Kansas City, Missouri, Kansas	156	185	75.4	223	245
Knoxville, Tennessee	29	36	71.9	46	50
Lakeland, Florida	43	56	45.9	112	122
Lancaster, Pennsylvania	16	18	34.9	46	50
Las Vegas–Paradise, Nevada	249	284	73.4	351	387
Little Rock–North Little Rock, Arkansas	35	69	70.3	89	98
Los Angeles, California	1,575	2,589	81.9	2,335	3,161
Louisville, Kentucky, Indiana	68	128	68.6	170	186
Madison, Wisconsin	20	29	75.1	36	39
McAllen–Edinburg–Pharr, Texas	48	64	67.9	85	94
Memphis, Tennessee, Mississippi, Arkansas	108	231	52.8	395	438
Miami, Florida	1,184	1,481	53.9	2,514	2,749
Milwaukee–Waukesha–West Allis, Wisconsin	95	133	73.4	165	180

TABLE 2. (Continued*) Estimated number and percentage of diagnoses of HIV infection† attributed to male-to-male sexual contact among persons aged ≥13 years, by location of residence — National HIV Surveillance System, United States and Puerto Rico, 2010**
Location of residence	HIV infection attributed to male-to-male sexual contact			Total diagnoses
Location of residence	Reported no.§	Estimated no.¶	% of total	Reported no.§	Estimated no.¶
Minneapolis-St. Paul–Bloomington, Minnesota, Wisconsin	169	236	69.5	307	340
Modesto, California	12	16	78.8	17	20
Nashville–Davidson–Murfreesboro, Tennessee	158	234	71.5	298	327
New Haven–Milford, Connecticut	34	51	37.7	104	136
New Orleans–Metairie–Kenner, Louisiana	152	244	55.8	404	437
New York, New York, New Jersey, Pennsylvania	2,013	3,347	54.5	4,669	6,140
Ogden–Clearfield, Utah	10	11	83.0	12	13
Oklahoma City, Oklahoma	67	98	62.4	143	157
Omaha–Council Bluffs, Nebraska, Iowa	37	54	60.2	81	90
Orlando, Florida	310	407	59.8	622	682
Oxnard–Thousand Oaks–Ventura, California	25	34	78.2	35	43
Palm Bay–Melbourne–Titusville, Florida	35	44	53.6	75	82
Philadelphia, Pennsylvania, New Jersey, Delaware, Maryland	484	—	—	1,192	—
Phoenix–Mesa–Scottsdale, Arizona	300	361	73.9	453	489
Pittsburgh, Pennsylvania	92	112	67.3	153	166
Portland–South Portland, Maine	16	22	61.9	30	36
Portland–Vancouver–Beaverton, Oregon, Washington	131	158	72.5	198	218
Poughkeepsie–Newburgh–Middletown, New York	20	32	34.4	70	94
Providence–New Bedford–Fall River, Rhode Island, Massachusetts	67	89	60.5	151	147
Provo–Orem, Utah	4	4	66.8	6	7
Raleigh–Cary, North Carolina	114	143	69.3	190	206
Richmond, Virginia	105	147	56.3	217	260
Riverside–San Bernardino–Ontario, California	242	319	71.5	366	447
Rochester, New York	71	105	67.3	118	156
Sacramento–Arden–Arcade–Roseville, California	106	140	59.6	191	234
St. Louis, Missouri, Illinois	202	294	68.3	380	430
Salt Lake City, Utah	32	36	59.0	57	62
San Antonio, Texas	159	207	69.5	273	298
San Diego–Carlsbad–San Marcos, California	372	469	74.5	515	630
San Francisco, California	553	729	70.4	873	1,035
San Jose–Sunnyvale–Santa Clara, California	89	128	70.8	144	180
San Juan–Caguas–Guaynabo, Puerto Rico	138	267	34.3	475	778
Scranton–Wilkes-Barre, Pennsylvania	11	12	34.9	30	34
Seattle, Washington	267	328	74.9	401	438
Springfield, Massachusetts	21	—	—	72	—
Stockton, California	39	51	47.3	87	107
Syracuse, New York	26	38	58.0	49	65
Tampa–St. Petersburg–Clearwater, Florida	317	404	63.6	578	635
Toledo, Ohio	17	24	63.6	35	38
Tucson, Arizona	57	77	73.1	96	105
Tulsa, Oklahoma	46	59	69.8	79	84
Virginia Beach–Norfolk–Newport News, Virginia, North Carolina	131	241	60.4	335	400
Washington, District of Columbia, Virginia, Maryland, West Virginia	589	—	—	1,715	—
Wichita, Kansas	30	35	63.5	49	55
Worcester, Massachusetts	13	—	—	61	—
Youngstown–Warren–Boardman, Ohio, Pennsylvania	9	23	58.7	37	40
Total	16,898	23,559	62.1	35,200	37,934
Abbreviations: HIV = human immunodeficiency virus; MSAs = metropolitan statistical areas. * Estimates result from statistical adjustment that accounted for reporting delays, but not for incomplete reporting. Cases without reported risk factors were assigned transmission categories using multiple imputation methods. † Includes all new diagnoses of HIV infection, regardless of stage of disease at diagnosis. § Includes reported numbers from 103 MSAs, 263 smaller metropolitan areas, and 198 nonmetropolitan areas. ¶ Includes estimated numbers only from 96 MSAs, 258 smaller metropolitan areas, and 198 nonmetropolitan areas located in states that had implemented confidential name-based HIV infection reporting by at least January 2007 and had reported these data to CDC since at least June 2007. Reported and estimated numbers smaller than 12 or percentages based on estimated numbers smaller than 12 are considered unreliable and should be interpreted with caution.

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