Wearing masks is a CDC-recommended* approach to reduce the spread of SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), by reducing the spread of respiratory droplets into the air when a person coughs, sneezes, or talks and by reducing the inhalation of these droplets by the wearer. On July 2, 2020, the governor of Kansas issued an executive order(†) (state mandate), effective July 3, requiring masks or other face coverings in public spaces. CDC and the Kansas Department of Health and Environment analyzed trends in county-level COVID-19 incidence before (June 1-July 2) and after (July 3-August 23) the governor's executive order among counties that ultimately had a mask mandate in place and those that did not. As of August 11, 24 of Kansas's 105 counties did not opt out of the state mandate(§) or adopted their own mask mandate shortly before or after the state mandate was issued; 81 counties opted out of the state mandate, as permitted by state law, and did not adopt their own mask mandate. After the governor's executive order, COVID-19 incidence (calculated as the 7-day rolling average number of new daily cases per 100,000 population) decreased (mean decrease of 0.08 cases per 100,000 per day; net decrease of 6%) among counties with a mask mandate (mandated counties) but continued to increase (mean increase of 0.11 cases per 100,000 per day; net increase of 100%) among counties without a mask mandate (nonmandated counties). The decrease in cases among mandated counties and the continued increase in cases in nonmandated counties adds to the evidence supporting the importance of wearing masks and implementing policies requiring their use to mitigate the spread of SARS-CoV-2 (1-6). Community-level mitigation strategies emphasizing wearing masks, maintaining physical distance, staying at home when ill, and enhancing hygiene practices can help reduce transmission of SARS-CoV-2.

An estimated 2.9 million new chlamydia infections occur in the United States each year. Among women, chlamydia can lead to serious adverse outcomes, including pelvic inflammatory disease and infertility. Chlamydia prevalence is highest among females aged 15-19 years. Despite long-standing recommendations directed at young, sexually active females, screening remains sub-optimal. Juvenile detention centers (JDCs) are uniquely situated to screen and treat high-risk adolescents. From 2009-2011, performance measure data on chlamydia screening coverage (proportion of eligible females screened) and positivity (proportion of females tested who were positive) were available from 126 geographically-dispersed JDCs in the United States. These facilities reported screening 55.2% of females entering the facilities (149,923), with a facility-specific median of 66.4% (range: 0%-100%). Almost half (44.4%) of facilities had screening coverage levels of 75%-100%. This screening resulted in the detection of 12,305 chlamydial infections, for an overall positivity of 14.7% (facility-specific median=14.9%, range: 0%-36.9%). In linear regression analysis, chlamydia positivity was inversely associated with screening coverage: as coverage increased, positivity decreased. The burden of chlamydia in JDCs is substantial; facilities should continue to deliver recommended chlamydia screening and treatment to females and identify mechanisms to increase coverage.

Young persons entering US jails and youth detention facilities have high rates of sexually transmitted diseases (STDs). The Centers for Disease Control and Prevention added STD screening guidelines specific to correctional settings to the 2010 STD Treatment Guidelines. This article summarizes published evidence from 1990 to 2009 used to develop the recommendations. The literature supports routine screening of adolescents and young women (aged ≤35 years, or on the basis of local institutional prevalence data) for chlamydia and gonorrhea because of high prevalence and the subsequent risk of adverse reproductive outcomes. Chlamydia positivity among young women (aged <20 years) in juvenile detention facilities and adult facilities is more than 14%. Men in correctional settings are also at high risk for chlamydia and gonorrhea. Among boys in juvenile detention facilities, chlamydia positivity is estimated at 6.6%; among young men in adult facilities, positivity is 16.6%. Screening men (to reduce sequelae among women) should be considered based on local epidemiology and resource availability. Syphilis screening is not strongly supported in published literature because of low prevalence and is not routinely recommended; however, some screening may be warranted based on local prevalence. Although there is a great diversity in the organization of correctional facilities, implementation of screening recommendations is possible owing to improvements in test technology (urine specimens) and through integration of a standard screening protocol. Based on the high burden of disease and substantial opportunities to reach a high-risk population, correctional facilities are important venues to target efforts to control STDs.

OBJECTIVE: Chlamydia re-infection data are used to inform and evaluate chlamydia control programmes. We quantitatively investigated the effect of denominator selection on estimating re-infection rates and trends. METHODS: Using data on women aged 15-44 years enrolled in Group Health Cooperative (GH), a Pacific Northwest health plan, annual chlamydia re-infection rates from 1998 to 2006 were calculated. Three different denominators were compared using person-years contributed by: (1) all women; (2) women with a prior documented chlamydial infection regardless of whether they were retested; and (3) women with a prior chlamydial infection who were retested within 14 months. RESULTS: From 1998 to 2006, among all women 15-44 years enrolled in GH, re-infection rates increased from 64 to 149 cases per 100 000 person-years. Among women with a prior infection, rates decreased from 10 857 to 8782 cases per 100 000 person-years. Among women with a prior infection who were retested, rates increased from 29 374 to 42 475 cases per 100 000 person-years. CONCLUSIONS: Using the same dataset, we demonstrate that it is possible to tell three different stories about the magnitude of rates and trends in chlamydia re-infection among women by using different denominators. All of these strategies have limitations, but restricting the denominator to women with a prior infection who are retested may best represent the population at-risk for re-infection. Still, rates do not account for additional factors influencing the number of re-infections diagnosed, including screening coverage and changes in test technology. Caution is needed in examining and comparing re-infection data.

BACKGROUND: Most sexually active people will be infected with a sexually transmitted infection (STI) at some point in their lives. The number of STIs in the United States was previously estimated in 2000. We updated previous estimates to reflect the number of STIs for calendar year 2008. METHODS: We reviewed available data and literature and conservatively estimated incident and prevalent infections nationally for 8 common STIs: chlamydia, gonorrhea, syphilis, herpes, human papillomavirus, hepatitis B, HIV, and trichomoniasis. Where available, data from nationally representative surveys such as the National Health and Nutrition Examination Survey were used to provide national estimates of STI prevalence or incidence. The strength of each estimate was rated good, fair, or poor, according to the quality of the evidence. RESULTS: In 2008, there were an estimated 110 million prevalent STIs among women and men in the United States. Of these, more than 20% of infections (22.1 million) were among women and men aged 15 to 24 years. Approximately 19.7 million incident infections occurred in the United States in 2008; nearly 50% (9.8 million) were acquired by young women and men aged 15 to 24 years. Human papillomavirus infections, many of which are asymptomatic and do not cause disease, accounted for most of both prevalent and incident infections. CONCLUSIONS: Sexually transmitted infections are common in the United States, with a disproportionate burden among young adolescents and adults. Public health efforts to address STIs should focus on prevention among at-risk populations to reduce the number and impact of STIs.

BACKGROUND: Chlamydia screening practices, positivity, and trends from 2004 to 2009 in publicly funded prenatal clinics have not been described. METHODS: A phone-based survey assessing chlamydia screening practices was conducted among a random sample of clinics providing prenatal services (prenatal, family planning, and integrated clinics: "prenatal clinics") that reported data to the Infertility Prevention Project (IPP) in 2008. Using existing IPP data, chlamydia positivity and trends were assessed among women aged 15 to 24 years seeking care in any prenatal clinic reporting ≥3 years of data to IPP from 2004 to 2009. Linear trends of the effect of year (a continuous variable) on positivity were evaluated using a correlated modeling approach with a random intercept where the unit of analysis was the individual clinic performing chlamydia tests (clinic-based analysis). Covariates included race, age, test technology, and geography. RESULTS: Of 210 sampled clinics, 166 (79%) completed the survey. Of these, 163 (98.2%) had documented chlamydia screening criteria. Most clinics screened all women during their first trimester and reported 100% screening coverage. From 2004 to 2009, 267,416 tests among women aged 15 to 24 years were reported to IPP from eligible prenatal clinics. Overall chlamydia positivity was 8.3%. Controlling for all covariates, positivity decreased from 2004 to 2009 (odds ratio: 0.93 per year, 95% confidence interval: 0.92, 0.95, 35% decrease overall). CONCLUSIONS: The substantial burden of chlamydia among young women tested in prenatal clinics reporting data to IPP suggests the continued need for routine screening. Decreasing trends from 2004 to 2009 in the IPP prenatal population correspond to findings of overall decreasing chlamydia prevalence in the United States.

We appreciate the thoughtful comments by Drs. Rekart and Brunham.1 While data reported through the Infertility Prevention Project (IPP) are useful for examining US chlamydia positivity trends as part of a larger chlamydia surveillance portfolio, including national case report data, population-based prevalence data, and prevalence data from special populations, IPP data are not suited for assessing trends in reinfection rates or changes in the estimated duration of infection. IPP data at the local level are particularly valuable in evaluating programmatic activities and guiding decision making. In addition, most family planning clinics reporting data to IPP are Title X clinics; for the majority of women receiving care at Title X clinics, these clinics are the stable, primary source of health care, suggesting that few women would be tested for chlamydia in an alternate venue.2 | While multiple studies, including ours, suggest that chlamydia prevalence in the United States is stable or decreasing,3–6 it is certainly possible that incidence is concurrently increasing. Our article does not examine chlamydia incidence but, rather, prevalence. A number of factors could explain increasing incidence if that was occurring. For example, as chlamydia screening coverage has increased, the average duration of infection has decreased, which could result in quicker acquisition of a repeat infection and thus lead to an increase in annual incidence. In essence, screening and treating more individuals may increase incidence among those who are treated. Rekart and Brunham indicate that arrested immunity as a result of expanded screening and treatment programs leading to an increased risk of reinfection independent of sexual risk factors may also play a role, among other possible factors.1 There are many factors that might explain our findings as well as possible increases in incidence; the inability to identify which factors are causing the effects should not be considered evidence for any one in particular. Support for the arrested immunity hypothesis would involve demonstration of immunity at the individual level following infection and changes in that immunity based on treatment.

BACKGROUND: Given recent increasing case rates of Chlamydia trachomatis infection, we evaluated trends in chlamydia rates and related health outcomes in women and men aged 15 to 44 years who were enrolled in a Pacific Northwest health plan. METHODS: We identified chlamydia, pelvic inflammatory disease (PID), ectopic pregnancy, and male urethritis cases occurring annually during 1997-2007 using computerized health plan databases, calculating rates per 100,000 person-years (py) by gender and 5-year age groups. We also calculated annual chlamydia testing rates. RESULTS: In women, chlamydia testing rates increased by approximately 23% (220 tests per 1000 py in 1997 to 270 tests per 1000 in 2007). Chlamydia diagnosis rates rose from 449 cases/100,000 py in 1997 to 806/100,000 in 2007, a 79% increase (P = 0.01). Increases were greatest during 2005-2007, also the period of major conversion to nucleic acid amplification test. PID rates in this interval declined steadily from 823 cases/100,000 py to 473/100,000 (P < 0.01). Ectopic pregnancy rates remained unchanged. In men, chlamydia testing rates increased nearly 3.5-fold, from 12 to 42 tests per 1000 py. Chlamydia rates for men also rose significantly throughout the study interval (from 91 cases/100,000 py to 218/100,000; P < 0.01) as did urethritis diagnosis rates (P < 0.01). CONCLUSION: Between 1997 and 2007, annual health plan chlamydia rates increased significantly for both women and men. These trends may be due in part to increased testing rates and increased use of more sensitive tests, but they likely do not explain the increased urethritis rates. During this same interval, we observed steady declines in PID rates, consistent with other national data sources.

BACKGROUND: We report the first population-based assessment of national trends in chlamydia prevalence in the United States. METHODS: We investigated trends in chlamydia prevalence in representative samples of the US population aged 14 to 39 years using data from five 2-year survey cycles of the National Health and Nutrition Examination Survey from 1999 to 2008. Prevalence estimates and 95% confidence intervals (CI) are reported stratified by age, gender, and race/ethnicity. Percent change in prevalence over this time period was estimated from regression models. RESULTS: In the 2007-2008 cycle, chlamydia prevalence among participants aged 14 to 39 years was 1.6% (95% CI: 1.1%-2.4%). Prevalence was higher among females (2.2%, 95% CI: 1.4%-3.4%) than males (1.1%, 95% CI: 0.7%-1.7%). Prevalence among non-Hispanic black persons was 6.7% (95% CI: 4.6%-9.9%) and was 2.5% (95% CI: 1.6%-3.8%) among adolescents aged 14 to 19 years. Over the five 2-year cycles, there was an estimated 40% reduction (95% CI: 8%-61%) in prevalence among participants aged 14 to 39 years. Decreases in prevalence were notable in men (53% reduction, 95% CI: 19%-72%), adolescents aged 14 to 19 years (48% reduction, 95% CI: 11%-70%), and adolescent non-Hispanic black persons (45%, reduction, 95% CI: 4%-70%). There was no change in prevalence among females aged 14 to 25 years, the population targeted for routine annual screening. CONCLUSIONS: On the basis of population estimates of chlamydia prevalence, the overall chlamydia burden in the United States decreased from 1999 to 2008. However, there remains a need to reduce prevalence in populations most at risk and to reduce racial disparities.

BACKGROUND: National notifiable disease data indicate that there were 99 cases of gonorrhea for every 100,000 persons in the United States in 2009, the lowest recorded gonorrhea rate in US history. However, the extent to which declining case reports signify a reduction in prevalence is unknown. METHODS: Gonorrhea prevalence was estimated among 16- to 24-year-old men and women entering the National Job Training Program (NJTP) between 2004 and 2009. Multivariate logistic regression was used to assess the probability of testing positive for gonorrhea over time. RESULTS: A total of 95,184 men and 91,697 women were screened for gonorrhea upon entry to the NJTP between 2004 and 2009. For women, gonorrhea prevalence increased from 2004 (2.6%) to 2006 (2.9%), then decreased steadily through 2009 (1.8%). For men, prevalence increased from 2004 (1.3%) to 2005 (1.6%), then decreased through 2009 (0.9%). Gonorrhea prevalence among black women decreased from 3.6% in 2004 to 2.5% in 2009 and was 2 to 4 times higher than prevalence among white women. Likewise, prevalence among black men decreased from 2.0% to 1.5% and was 8 to 22 times higher than prevalence among white men. After adjusting for gonorrhea risk factors, the odds of women and men testing positive for gonorrhea decreased by 50% and 40%, respectively, from 2004 to 2009. CONCLUSIONS: Declining trends in gonorrhea infection among NJTP entrants are similar to those observed in gonorrhea case report data, suggesting that the decrease in case reports is due to a decrease in prevalence. However, targeted interventions are needed to reduce gonorrhea infections in populations with disproportionate risk.

ICD-9 codes are conventionally used to identify pelvic inflammatory disease (PID) from administrative data for surveillance purposes. This approach may include non-PID cases. To refine PID case identification among women with ICD-9 codes suggestive of PID, a case-finding algorithm was developed using additional variables. Potential PID cases were identified among women aged 15-44 years at Group Health (GH) and Kaiser Permanente Colorado (KPCO) and verified by medical record review. A classification and regression tree analysis was used to develop the algorithm at GH; validation occurred at KPCO. The positive predictive value (PPV) for using ICD-9 codes alone to identify clinical PID cases was 79%. The algorithm identified PID appropriate treatment and age 15-25 years as predictors. Algorithm sensitivity (GH = 96.4%; KPCO = 90.3%) and PPV (GH = 86.9%; KPCO = 84.5%) were high, but specificity was poor (GH = 45.9%; KPCO = 37.0%). In GH, the algorithm offered a practical alternative to medical record review to further improve PID case identification.

BACKGROUND: Annual chlamydia screening is recommended for all sexually active women aged <25 years. Substantial limitations exist in ascertaining chlamydia trends. Reported case rates have increased likely due to increased screening and improved test technology. Other data suggest that prevalence has decreased. METHODS: Data from the Infertility Prevention Project (IPP), a national chlamydia screening program, were used to assess trends in chlamydia positivity from 2004 to 2008 among women aged 15 to 24 years who were tested in family planning clinics reporting data to IPP. Using the clinic as the unit of analysis, a correlated, longitudinal data analysis with a random intercept was conducted among clinics reporting ≥3 years of data during the analysis timeframe. Sensitivity analyses were performed to address the impact of various clinic participation levels in addition to the assessment of various correlation structures. RESULTS: Over 5 million chlamydia tests were reported to IPP family planning clinics from 2004 to 2008. A majority of tests were conducted among white women (clinic-specific mean: 63.2%, interquartile range: 37.6%-91.5%); the clinic-specific mean percent of tests conducted among black women was 17.9% (interquartile range: 0.8%-25.7%). Overall chlamydia positivity from 2004 to 2008 was 7.0%. The odds ratio associated with a single year change (1.00; 95% confidence interval: 0.99, 1.00) suggested that chlamydia positivity did not change from 2004 to 2008, after controlling for clinic-specific population factors (age, race, test usage, and geography). CONCLUSIONS: Findings support previous analyses suggesting that chlamydia prevalence is not increasing despite apparent increasing rates based on case reports.

The authors applied a time-series approach to assess the temporal trend of racial disparity in chlamydia prevalence between young, socioeconomically disadvantaged blacks and whites entering the US National Job Training Program. Racial disparity was defined as the arithmetic difference between age group-, specimen type-, and region of residence-standardized chlamydia prevalences in blacks and whites. A regression with autoregressive moving average errors model was employed to adjust for serial correlation. Data from 46,849 women (2006-2008) and 136,892 men (2004-2008) were analyzed. Racial disparity significantly decreased among women (by an average of 0.122% per 2-month interval; P < 0.05) but not among men (-0.010%, P = 0.57). Chlamydia prevalence significantly declined for black women (-0.139% per 2-month interval; P = 0.004), black men (-0.045%, P < 0.001), and white men (-0.035%, P = 0.002) but not for white women (-0.028%, P = 0.413). Despite the decreases among black women and black men, the black-white disparities remained high for both sexes; in 2008, the racial disparity was 8.1% (95% confidence interval: 6.8, 9.3) for women and 9.0% (95% confidence interval: 8.4, 9.6) for men. These findings suggest that current chlamydia control efforts may be reaching young black men and women but need to be scaled up or modified to address the excess risk among blacks.

In this issue, Bernstein et al. report on a structural intervention aimed at reducing chlamydia screening among women aged ≥26 years.1 This article, though brief, provides an opportunity to highlight several issues related to chlamydia screening and sexually transmitted disease (STD)/human immunodeficiency virus (HIV) prevention in general. | The importance of screening young women for chlamydia should be reemphasized. The United States Preventive Services Task Force (USPSTF) recommends annual chlamydia screening for all sexually active young women aged <25 years.2 This is an “A” recommendation, meaning there is good evidence that the benefits of screening outweigh the harms.3 Conversely, USPSTF recommends against routinely screening women aged ≥25 years, unless the individuals are at increased risk of infection (e.g., history of sexually transmitted infections, new or multiple sex partners, inconsistent condom use, exchanging sex for money or drugs).

In 2002, 2 million American women of reproductive age were infertile. Infertility is also common among men. The Centers for Disease Control and Prevention (CDC) conducts surveillance and research on the causes of infertility, monitors the safety and efficacy of infertility treatment, and sponsors national prevention programs. A CDC-wide working group found that, despite this effort, considerable gaps and opportunities exist in surveillance, research, communication, and program and policy development. We intend to consult with other federal agencies, professional and consumer organizations, the scientific community, the health care community, industry, and other stakeholders, and participate in the development of a national public health plan for the prevention, detection, and management of infertility.

BACKGROUND: We explored the utility of using insurance claims data for surveillance of pelvic inflammatory disease (PID). PID rates are an important indicator of population level trends in reproductive morbidity; however, data available to monitor PID trends are limited. National survey data are currently used to estimate PID rates in the United States, but a declining number of cases threaten their future usefulness. METHODS: We performed a retrospective analysis of PID diagnosis rates using administrative claims data from 2001 to 2005. Diagnostic codes were used to identify women aged 15 to 44 in the study population that were diagnosed with acute PID as inpatients, in emergency departments, and in outpatient ambulatory settings. RESULTS: Rates of PID diagnoses among privately insured women declined significantly from 2001 to 2005 among all age groups examined and within all geographic regions. Annual PID diagnosis rates decreased from 317.0 to 236.0 per 100,000 enrollees, representing a 25.5% decline over the study period. The highest rates of PID were among 25- to 29-year-olds (352.8 per 100,000 in 2005) and among those residing in the South (314.3 per 100,000 in 2005). Most women (70.1%) received PID care through physician offices and other outpatient facilities; of these women, approximately 40% were treated by an obstetrician/gynecologist. CONCLUSIONS: The decline in PID diagnoses corresponds with previous reports from national surveys. Claims data offer a much needed new data source that will allow for continued monitoring of PID among a broad population in both inpatient and outpatient clinical settings.

OBJECTIVE: To analyze 5-year prevalence trends in Chlamydia trachomatis infections among high-risk young men and women aged 16 to 24 years entering the National Job Training Program, where universal screening is required. METHODS: Entrance exams conducted in over 100 National Job Training Program centers from 2003 to 2007 were considered. Women provided cervical specimens tested using either a DNA hybridization probe (PACE 2, Gen-Probe, San Diego, CA) or a strand displacement amplification test (SDA, BD ProbeTec ET, Becton-Dickinson, Sparks, MD). In the absence of a pelvic exam, urine specimens were tested using SDA. PACE 2 testing was performed predominately from 2002 to 2005; from 2005 to 2007, SDA was used. All male testing was conducted using SDA on urine specimens. Chlamydia prevalence trends were assessed for women and men, using logistic regression models. Adjusted odds ratios (AOR), 95% confidence intervals (CI), and P-values were calculated. RESULTS: Approximately 15,000 women and 30,000 men were screened annually for chlamydia. Among both sexes, adjusted prevalence declined significantly from 2003 to 2007. In 2003, crude prevalence among women was 9.9%; in 2007, prevalence was 13.7%. However, after controlling for covariates, including increasingly sensitive tests, the model indicated a significant declining prevalence trend (AOR: 0.95, CI: 0.93-0.97, 4.6% decrease in odds per year). Among men, crude prevalence in 2003 was 8.4%; in 2007, prevalence was 8.3%; after controlling for possible confounding, a significant decline in prevalence was also detected (AOR: 0.98, CI: 0.96-0.99, 1.9% decrease in odds per year). CONCLUSIONS: In a relatively stable, high-risk population of young women and men, adjusted chlamydia prevalence declined from 2003 to 2007. Test technology plays a critical role in interpreting rates and should be considered whenever chlamydia rates are examined.

BACKGROUND: Chlamydia trachomatis screening test positivity among women in the United States has remained high, leading researchers to suggest that programs should also screen men. Men have been screened in Philadelphia prisons since 2002. Philadelphia prisons are similar to jails in other jurisdictions; in 2003 the median duration of incarceration was 17 days. We studied whether screening and treating men in prison influenced C. trachomatis infection among women living in their communities. METHODS: We divided the city into 2 areas: "high-treatment" (high percentage of men were treated for C. trachomatis detected in prison) and "low-treatment" (low percentage of men were treated for C. trachomatis detected in prison). We compared changes in test positivity among women from those areas, who were tested in family planning clinics during the 2 years before versus the 3 years after the male prison screening program began. RESULTS: In 2002 to 2004, prison screening led to treatment of 1054 infections among 23,203 men aged 20 to 24 years living in high-treatment areas and 98 infections among 21,057 men aged 20 to 24 years in low-treatment areas. Test positivity declined among 20- to 24-year-old women in both areas. In high-treatment areas, positivity decreased 9.1% per year from 1999 to 2001 and 4.9% per year from 2001 to 2004. In low-treatment areas, positivity decreased 13.2% per year from 1999 to 2001 and 7.5% per year from 2001 to 2004. CONCLUSION: C. trachomatis test positivity among 20- to 24-year-old women tested in family planning clinics continued to decrease after men were treated for C. trachomatis; however, we found no evidence that the continued decrease was due to the new prison screening program.