Update: Influenza Activity—United States, 1998-99 SeasonIncreases in Unsafe Sex and Rectal Gonorrhea Among Men Who Have Sex With Men— San Francisco, California, 1994-1997HIV Testing— United States, 1996Update: Influenza Activity—United States, 1998-99 SeasonIncreases in Unsafe Sex and Rectal Gonorrhea Among Men Who Have Sex With Men— San Francisco, California, 1994-1997HIV Testing— United States, 1996 FREE

MMWR. 1999;48:25-27

In collaboration with the World Health Organization (WHO), its collaborating laboratories, and state and local health departments, CDC conducts surveillance to monitor influenza activity and to detect antigenic changes in the circulating strains of influenza viruses. This report summarizes influenza surveillance in the United States from October 4, 1998, to January 9, 1999, which indicates that overall influenza activity was low.

As of January 9, the 110 WHO and National Respiratory Enteric Virus Surveillance System collaborating laboratories in the United States had tested 20,972 specimens (by culture or direct antigen-detection techniques) for respiratory viruses. Of these, 401 (2%) were positive for influenza viruses; 293 (73%) were influenza A, and 108 (27%) were type B. Of the 95 (32%) influenza A isolates that have been subtyped, 93 (98%) were influenza A(H3N2) and two (2%) were influenza A(H1N1). Since October 4, all of the influenza A(H3N2) viruses antigenically characterized by CDC were similar to A/Sydney/5/97, the H3N2 component of the 1998-99 influenza vaccine. One influenza A(H1N1) isolate was antigenically characterized as an A/Bayern/7/95-like virus that is antigenically distinct from A/Beijing/262/95, the H1N1 vaccine strain. However, the 1998-99 A(H1N1) vaccine strain produces high titers of antibodies that cross react with A/Bayern/7/95.¹ All 15 of the influenza B viruses antigenically characterized by CDC are similar to B/Beijing/184/93, the recommended type B vaccine strain.

Since October 4, 1998, 41 states have reported laboratory-confirmed influenza. Influenza A(H3N2) viruses were reported from 24 states, influenza A(H1N1) viruses from two states, influenza B viruses from 26 states, and influenza A (not subtyped) viruses from 32 states. For the week ending January 9, 1999, New York City reported widespread* influenza activity, 10 states reported regional activity, and 35 states reported sporadic activity. The overall percentage of patient visits to sentinel physicians for influenza-like illness remained within baseline levels (0-3%) during the entire period. The percentage of deaths attributed to pneumonia and influenza reported by the 122 Cities Pneumonia and Influenza Mortality Surveillance System ranged from 6% to 7% and intermittently exceeded the epidemic threshold† for a combined total of 5 of 14 weeks, but has not remained above the epidemic threshold for >2 consecutive weeks.

Participating state and territorial epidemiologists and state public health laboratory directors. World Health Organization collaborating laboratories, National Respiratory Enteric Virus Surveillance System collaborating laboratories. Sentinel Physicians Influenza Surveillance System. WHO Collaborating Center for Reference and Research on Influenza, Influenza Br, Div of Viral and Rickettsial Diseases, National Center for Infectious Diseases, CDC.

The findings in this report indicate that, despite institutional outbreaks in several states, this influenza season has been relatively mild. However, influenza activity has increased since mid-December and may increase during subsequent weeks. Although the optimal time for influenza vaccination is October through mid-November, influenza vaccine should still be offered to unvaccinated high-risk persons, health-care providers, caregivers, and household contacts of high-risk persons even after influenza activity has been detected in the community.

All influenza A strains and most influenza B strains isolated in the United States that have been characterized by CDC are well matched by the 1998-99 influenza vaccine. A/Sydney/5/97-like (H3N2) viruses were the predominant influenza viruses isolated in the United States during the 1997-98 season and were isolated throughout 1998.^2- 4 Even when the match between circulating strains and vaccine strains is good, outbreaks of influenza can still occur in vaccinated persons. Therefore, use of the antiviral agents amantadine and rimantadine in addition to influenza vaccination may help prevent and control influenza A but not influenza B, especially among persons at high risk for influenza-related complications and in institutions such as nursing homes.^5- 6 These drugs are 70%-90% effective in preventing influenza A infections and reduce the severity and duration of symptoms when administered within 48 hours of illness onset.

Commercially available point-of-care rapid diagnostic tests for influenza include one test that detects only influenza A virus and two tests that detect both influenza A and B viruses but do not distinguish between the infections. Rapid diagnostic tests for influenza in institutional outbreaks are most useful when used in conjunction with viral cultures. Rapid identification of influenza virus infection is important because prevention measures, such as cohorting and isolating infected and symptomatic persons, can be implemented more quickly.

Influenza surveillance data are updated weekly throughout the season. Summary reports are available through CDC's voice information system, (888) 232-3228, or fax information system, (888) 232-3299, by requesting document number 361100 and entering the telephone number to which the document should be transmitted, or through CDC's National Center for Infectious Diseases, Division of Viral and Rickettsial Diseases, Influenza Branch World Wide Web site http://www.cdc.gov/ncidod/diseases/flu/weekly.htm.

*Levels of activity are 1) no activity; 2) sporadic—sporadically occurring influenza-like illness (ILI) or culture-confirmed influenza with no outbreaks detected; 3) regional—outbreaks of ILI or culture-confirmed influenza in counties with a combined population of <50% of the state's total population; and 4) widespread—outbreaks of ILI or culture-confirmed influenza in counties with a combined population of >50% of the state's total population.

†The epidemic threshold is 1.645 standard deviations above the seasonal baseline. The expected seasonal baseline is projected using a robust regression procedure in which a periodic regression model is applied to observed percentage of deaths from pneumonia and influenza since 1983.

MMWR. 1999;48:45-48

1 figure omitted

Reductions in AIDS cases among men who have sex with men (MSM) have been attributed in part to widespread declines in unprotected anal sex since the mid-1980s¹ and use of increasingly effective antiretroviral therapy (ART) since the mid-1990s.² Because data about HIV infection incidence are limited, other indicators of transmission risk have been used. In San Francisco, data from annual behavioral surveys among MSM (1994-1997) and from the sexually transmitted disease (STD) surveillance program (1990-1997) were analyzed to characterize changes in HIV risk behaviors of MSM and changes in incidence of male rectal gonorrhea. This report describes the findings of these analyses, which indicate increases in unsafe sexual behavior and increases in rates of rectal gonorrhea among MSM.

From 1994 through 1997, volunteers in The Stop AIDS Project, a San Francisco community-based organization, conducted standardized annual surveys in which MSM were approached in various settings (e.g., neighborhoods, clubs, bars, and outdoor events) and asked to respond to a peer-administered, one-page questionnaire. Persons were excluded if they had participated previously during the same year. Methods were identical across years. First-time interviews were completed among 21,857 MSM; 6223, 5989, 5472, and 4173 interviews were completed each respective year. Demographic and sexual behavior information was collected annually; in 1997, subjects were asked whether they knew the HIV serostatus of their sex partners. In the survey, unprotected anal intercourse (UAI) was defined as insertive or receptive anal sex during the previous 6 months without always using condoms. Multiple partners was defined as more than one sex partner during the previous 6 months. Male rectal gonorrhea data reported to the San Francisco Department of Public Health, Sexually Transmitted Disease Control Section, were reviewed. The annual incidence from 1994 through 1997 was calculated as cases per 100,000 adult men aged ≥15 years (1990 U.S. census data were used for the denominator). Changes in sexual behaviors and rectal gonorrhea incidence over time were assessed using the chi-square test for trend.

The proportion of surveyed MSM who reported having had anal sex increased from 57.6% (95% confidence interval [CI]=56.4%-58.9%) in 1994 to 61.2% (95% CI=60.1%-63.1%) in 1997 (p<0.01). Among MSM who had had anal sex, the proportion reporting "always" using condoms declined from 69.6% (95% CI=68.1%-71.1%) in 1994 to 60.8% (95% CI=58.9%-62.7%) in 1997 (p<0.01). The most pronounced decline in consistent condom use occurred among men aged 26-29 years (from 68.2% [95% CI=64.8%-71.5%] in 1994 to 58.0% [95% CI=53.7%-62.1%] in 1997). The proportion of men who reported having had multiple sex partners and UAI increased from 23.6% (95% CI=21.9%-25.4%) in 1994 to 33.3% (95% CI=31.1%-35.6%) in 1997 (p<0.01). The largest increase in this risk behavior was among respondents aged ≤25 years (from 22.0% [95% CI=18.4%-25.9%] in 1994 to 32.1% [95% CI=27.7%-36.7%] in 1997; p<0.01). Decreasing consistent condom use and increasing proportions of MSM reporting UAI with multiple partners occurred in all racial/ethnic groups. In 1997, 45% (95% CI=41.4%-48.8%) of 865 MSM who had had UAI during the previous 6 months also reported not knowing the HIV serostatus of all their sex partners. Among 525 MSM who had had UAI and multiple partners during the previous 6 months, 68.0% (95% CI=63.9%-72.7%) reported not knowing the HIV serostatus of all their sex partners.

Male rectal gonorrhea incidence declined from 1990 through 1993 (42, 33, 23, and 20 per 100,000 adult men, respectively). From 1994 through 1997, the incidence increased from 21 to 38 per 100,000 adult men (p<0.01). This increase in incidence was observed in all racial/ethnic and age groups but was highest among men aged 25-34 years (from 41 to 83 cases per 100,000 men aged 25-34 years, p<0.01).

KA Page-Shafer, PhD, W McFarland, MD, R Kohn, J Klausner, MD, MH Katz, MD, San Francisco Dept of Public Health, San Francisco; D Wohlfeiler, MPH, S Gibson, MSW, The Stop AIDS Project, San Francisco, California. Prevention Svcs Research Br, Program Evaluation Research Br, International Activities Br, Div of HIV/AIDS Prevention, and Epidemiology and Surveillance Br, Div of Sexually Transmitted Diseases Prevention, National Center for HIV, STD, and TB Prevention, CDC.

The data described in this report suggest that increases in unsafe sexual behavior have occurred among MSM in San Francisco, resulting in increased risk for HIV infection and transmission. These data provide additional insight to a previous report of increasing gonorrhea among MSM in selected STD clinics³ and document significant increases during 1994-1997 in rectal gonorrhea (a direct measure of UAI) and self-reported UAI among MSM.

The increases in reported risk behaviors and the increases in STDs in San Francisco coincide with the expanded availability of effective ART in San Francisco and the United States. Although ART can result in decreased viral load and decreased risk for HIV transmission, advances in HIV treatment and the resulting declines in AIDS deaths in San Francisco and nationally might lead to increased risk behavior by MSM who perceive that HIV infection can be managed effectively.⁴ Because the prevalence of HIV infection among MSM in San Francisco is high, small increases in unsafe behaviors in this population may result in increases in HIV infection incidence. Recent data do not show changes in HIV infection incidence among young MSM (aged 18-29 years) in San Francisco.⁵ However, HIV transmission may lag behind the transmission of other STDs, including gonorrhea, for several reasons (e.g., differences in infectivity and treatment).⁶

That increases in UAI may represent sex between mutually monogamous persons with concordant HIV serostatus (i.e., "negotiated safety") seems unlikely. One third of MSM reported UAI with multiple partners during the previous 6 months. Substantial numbers of men interviewed in 1997 reported not knowing the HIV infection status of all their partners. In addition, increases in rectal gonorrhea are inconsistent with increases in negotiated safe sex behaviors between MSM.

The findings in this study are subject to at least four limitations. First, the sample of MSM in The Stop AIDS Project surveys may not be representative of the general MSM community in San Francisco. Second, the questionnaire did not distinguish insertive versus receptive anal sex, and it did not inquire specifically about condom use with persons whose HIV serostatus was unknown. Third, survey respondents who reported UAI may not be similar to persons who acquired rectal gonorrhea. Fourth, the survey was not designed to assess the association between decreases in AIDS prevalence, AIDS deaths, or other factors and the described risk behaviors. However, the population surveyed was large, and increases in reported risk behaviors were consistent across all age and racial/ethnic groups. Other studies have described high and increasing rates of sexual risk behavior among MSM in San Francisco,⁷ elsewhere in the United States,⁸ and in Canada.⁹

Male rectal gonorrhea is increasing among MSM amidst an overall decline in nationwide gonorrhea rates.¹⁰ During 1993-1997, national gonorrhea surveillance demonstrated an annual increase in the proportion of cases in males compared with cases in females in western states (CDC, unpublished data) consistent with an increase in gonorrhea infection among MSM.

The data presented in this report suggest that the substantial reduction in sexual risk behaviors among MSM and the decreases in rectal gonorrhea during the 1980s and early 1990s cannot be assumed to be maintained indefinitely. The availability of ART and the possible perception of lower risk for infection from persons receiving ART may lead to misunderstandings and complacency toward safe-sex messages. MSM of all ages and races/ethnicities in San Francisco continue to engage in behaviors that put them at high risk for HIV infection, and HIV prevalence is highest among the MSM populations compared with heterosexual populations. As the epidemic continues, it remains important to maintain resources for prevention activities targeted toward MSM across all racial/ethnic and age groups. Public health prevention and community-based outreach efforts to reduce risk behaviors and STDs remain crucial to reach these populations.

MMWR. 1999;48:52-55

1 table, 1 figure omitted

Human immunodeficiency virus (HIV) infection is one of the leading causes of morbidity and mortality in the United States. HIV testing, in conjunction with counseling and other preventive services, can reduce the risk for HIV infection and appropriately link infected persons to treatment. To characterize HIV testing by region, state, and sex, CDC analyzed data from the 1996 Behavioral Risk Factor Surveillance System (BRFSS). This report summarizes the results of that analysis, which indicate a high degree of variability in HIV testing throughout the United States.

BRFSS is a state-specific, random-digit-dialed telephone survey of the U.S. population aged ≥18 years. In 1996, all 50 states and the District of Columbia (DC) participated in BRFSS. The 1996 survey included 14 questions about HIV/acquired immunodeficiency syndrome (AIDS)-related knowledge and attitudes and HIV-antibody testing history. The questions were restricted to persons aged <65 years, except in California, where the questions were asked of persons aged <45 years. In 1996, 97,006 persons responded to these questions (state-specific range: 899-3653). Data were weighted by demographic characteristics and by selection probabilities. Confidence intervals were calculated using SUDAAN to account for the complex survey design.

A mean of 42% of persons (range: 26% [South Dakota] to 60% [DC]) answered yes to the question "Have you ever had your blood tested for HIV?" Persons who answered "yes" were asked "What was the main reason you had your last blood test for HIV?" Responses were divided into two categories: those who chose to be tested for personal or health reasons (i.e., voluntarily tested) (responses included: "just to find out if infected," "for routine checkup," "doctor referral," "sex partner referral," "because of pregnancy," or "other"), and those who were tested for other reasons (e.g., military induction, insurance, and employment). A mean of 22% of persons (range: 10% [South Dakota] to 45% [DC]) reported obtaining HIV-antibody tests for voluntary reasons.

The rate of AIDS cases in 1996 was compared with HIV testing percentages in 1996. In general, in states where the AIDS rate was high, HIV testing also tended to be high. For example, DC had the highest AIDS rate and the highest testing percentage; Florida ranked third in both categories. In comparison, rates of overall testing and voluntary testing were lower in the Midwest, where the AIDS rate is low.

A mean of 44% of men reported having ever been tested for HIV (range: 28% [South Dakota] to 62% [DC]) (Table 1). A mean of 40% of women reported having ever been tested for HIV (range: 23% [North Dakota] to 57% [DC]). In 45 states and DC, a greater percentage of men reported ever being tested for HIV than women. The states with the greatest difference by sex of ever being tested for HIV were North Dakota (11%), Hawaii (10%), and New York (9%). The states with the smallest differences were Alaska, Delaware (both 0.5%), and Texas (0.6%).

A mean of 20% of men reported that their most recent HIV test was voluntary (range: 8% [South Dakota] to 46% [DC]) (Table 1). A mean of 25% of women reported that their most recent HIV test was voluntary (range: 12% [North Dakota] to 45% [DC]). In 49 states, a greater percentage of women reported being voluntarily tested than men. The sex-specific difference in reports of being voluntarily tested ranged from 0.1% in New York and Indiana to 13% in California.

J Cook, MBA, Alabama; P Owen, Alaska; B Bender, MBA, Arizona; J Senner, PhD, Arkansas; B Davis, PhD, California; M Leff, MSPH, Colorado; M Adams, MPH, Connecticut; F Breukelman, Delaware; C Mitchell, District of Columbia; S Hoecherl, Florida; L Martin, MPH, Georgia; AT Onaka, PhD, Hawaii; J Aydelotte, Idaho; B Steiner, MS, Illinois; K Horvath, Indiana; A Wineski, Iowa; M Perry, Kansas; K Asher, Kentucky; R Jiles, PhD, Louisiana; D Maines, Maine; A Weinstein, MA, Maryland; D Brooks, MPH, Massachusetts; H McGee, MPH, Michigan; N Salem, PhD, Minnesota; D Johnson, Mississippi; T Murayi, PhD, Missouri; P Feigley, PhD, Montana; M Metroka, Nebraska; E DeJan, MPH, Nevada; L Powers, MA, New Hampshire; G Boeselager, MS, New Jersey; W Honey, MPH, New Mexico; TA Melnik, DrPH, New York; K Passaro, PhD, North Carolina; J Kaske, MPH, North Dakota; P Pullen, Ohio; N Hann, MPH, Oklahoma; J Grant-Worley, MS, Oregon; L Mann, Pennsylvania; J Hesser, PhD, Rhode Island; D Shepard, South Carolina; M Gildemaster, South Dakota; D Ridings, Tennessee; K Condon, Texas; R Giles, Utah; C Roe, MS, Vermont; L Redman, MPH, Virginia; K Wynkoop-Simmons, PhD, Washington; F King, West Virginia; P Imm, MS, Wisconsin; M Futa, MA, Wyoming. Behavioral Risk Factor Surveillance System, Behavioral Surveillance Br, Div of Adult and Community Health, National Center for Chronic Disease Prevention and Health Promotion, CDC.

The findings in this report document a high degree of state-specific variability in self-reported HIV-antibody tests in the United States. Previous reports suggest this variability probably represents state-specific differences in such factors as prevalence of HIV infection and the activities of HIV-prevention and education programs.¹

The success of a health-promotion program depends on the level of participation of clients. Although HIV testing and counseling does not affect behavior change similarly across all population groups, in general, persons who voluntarily receive HIV testing are more likely to undergo counseling and modify their behaviors than those who receive testing for other reasons.² As a result, tracking overall testing rates and voluntary testing rates can help target health-promotion efforts.

The findings in this report are subject to at least two limitations. First, because BRFSS excluded persons without telephones, some persons at high risk for HIV infection probably were excluded. Second, because the BRFSS relies on self-reported data, some bias is expected.

HIV testing can help reach at-risk persons with counseling and other prevention services and link infected persons with needed health-care services. General population surveys, such as BRFSS, provide data to assess the use of HIV testing services across geographical areas. However, not all persons need to be tested for HIV. CDC recommends HIV counseling and testing services for persons with specific risk factors for HIV infection and in specific screening settings (e.g., tissue donation and pregnancy). Prevention programs should be structured to increase the proportion of at-risk persons who receive HIV-testing services.