U.S. Women with Invasive Cervical Cancer: Characteristics and Potential Barriers to Prevention.

Objectives: Although invasive cervical cancer (ICC) rates have declined since the advent of screening, the annual age-adjusted ICC rate in the United States remains 7.5 per 100,000 women. Failure of recommended screening and management often precedes ICC diagnoses. The study aimed to evaluate characteristics of women with incident ICC, including potential barriers to accessing preventive care. Materials and Methods: We abstracted medical records for patients with ICC identified during 2008-2020 in five U.S. population-based surveillance sites covering 1.5 million women. We identified evidence of adverse social and medical conditions, including uninsured/underinsured, language barrier, substance use disorder, incarceration, serious mental illness, severe obesity, or pregnancy at diagnosis. We calculated descriptive frequencies and compared potential barriers by race/ethnicity, and among women with and without symptoms at diagnosis using chi-square tests. Results: Among 1,606 women with ICC (median age: 49 years; non-White: 47.4%; stage I: 54.7%), the majority (68.8%) presented with symptoms. Forty-six percent of women had at least one identified potential barrier; 15% had multiple barriers. The most common potential barriers among all women were being underinsured/uninsured (17.3%), and language (17.1%). Presence of any potential barrier was more frequent among non-White women and women with than without symptoms (p < 0.05). Conclusions: In this population-based descriptive study of women with ICC, we identified adverse circumstances that might have prevented women from seeking screening and treatment to prevent cancer. Interventions to increase appropriate cervical cancer screening and management are critical for reducing cervical cancer rates.

Effectiveness of a Messenger RNA Vaccine Booster Dose Against Coronavirus Disease 2019 Among US Healthcare Personnel, October 2021-July 2022.

Background: Protection against symptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (coronavirus disease 2019 [COVID-19]) can limit transmission and the risk of post-COVID conditions, and is particularly important among healthcare personnel. However, lower vaccine effectiveness (VE) has been reported since predominance of the Omicron SARS-CoV-2 variant. Methods: We evaluated the VE of a monovalent messenger RNA (mRNA) booster dose against COVID-19 from October 2021 to June 2022 among US healthcare personnel. After matching case-participants with COVID-19 to control-participants by 2-week period and site, we used conditional logistic regression to estimate the VE of a booster dose compared with completing only 2 mRNA doses >150 days previously, adjusted for multiple covariates. Results: Among 3279 case-participants and 3998 control-participants who had completed 2 mRNA doses, we estimated that the VE of a booster dose against COVID-19 declined from 86% (95% confidence interval, 81%-90%) during Delta predominance to 65% (58%-70%) during Omicron predominance. During Omicron predominance, VE declined from 73% (95% confidence interval, 67%-79%) 14-60 days after the booster dose, to 32% (4%-52%) ≥120 days after a booster dose. We found that VE was similar by age group, presence of underlying health conditions, and pregnancy status on the test date, as well as among immunocompromised participants. Conclusions: A booster dose conferred substantial protection against COVID-19 among healthcare personnel. However, VE was lower during Omicron predominance, and waning effectiveness was observed 4 months after booster dose receipt during this period. Our findings support recommendations to stay up to date on recommended doses of COVID-19 vaccines for all those eligible.

HPV type-specific trends in cervical precancers in the United States, 2008 to 2016.

Declines in cervical intraepithelial neoplasia grades 2 to 3 and adenocarcinoma in situ (CIN2+) observed among young women suggest impact from human papillomavirus (HPV) vaccination. To further evaluate vaccine impact including cross-protection and type replacement, we described high-risk (HR)-HPV type-specific cervical precancer incidence rates among women aged 20 to 39 years, 2008 to 2016. We analyzed cross-sectional population-based data on 18 344 cases of CIN2+ from a 5-site surveillance system. Diagnostic specimens were tested for individual HPV types, including 14 HR-HPV types (HPV16/18/31/33/35/39/45/51/52/56/58/59/66/68). We estimated age-specific annual HR-HPV type-specific CIN2+ incidence per 100 000 screened women for individual types, vaccine HR-HPV types (HPV16/18) and nonvaccine HR-HPV types (non-HPV16/18). We evaluated trends using average annual percent changes (AAPC) and 95% confidence intervals (CI), and estimated total declines by comparing 2015-2016 to 2008-2009 using incidence rate ratios. Among 20-24-year-olds, HPV16/18-CIN2+ declined from 2008 through 2016 (AAPC: -21.3%, 95% CI: -28.1%, -13.8%), whereas no trend was observed for non-HPV16/18-CIN2+ (AAPC: -1.8%, 95% CI: -8.1%, 4.9%). After 2010, CIN2+ among 20-24-year-olds was more often caused by nonvaccine vs vaccine HR-HPV types. No significant declining trends were observed in older age groups. In 2015-2016 compared with 2008-2009, HPV16-CIN2+ declined 78%, HPV18-CIN2+ 72% and HPV31-CIN2+ 51% among 20-24-year-olds; no increases were observed in type-specific CIN2+ incidence. Among 25-29-year-olds, HPV16-CIN2+ declined 18%; CIN2+ attributed to seven nonvaccine types increased significantly. No significant declines were observed in older groups. Significant declines in HPV16/18-CIN2+ in 20-24-year-olds and HPV16-CIN2+ in 25-29-year-olds corroborate impact of HPV vaccination. A declining trend in HPV31-CIN2+ is consistent with cross-protection from vaccination.

Trends in Precancerous Cervical Lesions by Area-Based Measures of Poverty, Race, and Ethnicity, Connecticut, 2008-2018.

OBJECTIVES: Trends in the incidence of precancerous cervical lesions can be monitored to evaluate the impact of human papillomavirus (HPV) vaccination. The objective of this analysis was to determine whether declines in precancerous cervical lesions varied by area-based measures of poverty, race, and ethnicity. METHODS: We analyzed 11 years of incidence data (2008-2018) from a statewide active surveillance system of precancerous cervical lesions in Connecticut. We divided area-based measures of poverty, race, and ethnicity (percentage of the population in a census tract who were living below the federal poverty level, who were Black, and who were Hispanic) at the census-tract level into 4 groups (<5.0%, 5.0%-9.9%, 10.0%-19.9%, ≥20.0%) using recommended cut points from the Public Health Disparities Geocoding Project. We estimated incidence rates and average annual percentage changes (AAPCs) stratified by age and each area-based measure using Joinpoint regression software. We used total population and estimated screened population as denominators for each age group to calculate rates and AAPCs. RESULTS: During 2008-2018 in Connecticut, 18 878 women aged 21-39 were diagnosed with precancerous cervical lesions. After adjusting for screening, the largest declines occurred among women aged 21-24 (AAPC = -11.5%; 95% CI, -13.6% to -9.4%). We found significant and similar annual declines (~10%-12%) in this age group across all 4 levels of poverty, race, and ethnicity. CONCLUSIONS: This analysis adds to the growing body of evidence demonstrating the positive impact of population-level HPV vaccination among young women that appears similar across area-based measures of sociodemographic characteristics. Monitoring is necessary to ensure the continuation of this progress in all communities.

Practices and activities among healthcare personnel with severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection working in different healthcare settings-ten Emerging Infections Program sites, April-November 2020.

Healthcare personnel with severe acute respiratory coronavirus virus 2 (SARS-CoV-2) infection were interviewed to describe activities and practices in and outside the workplace. Among 2,625 healthcare personnel, workplace-related factors that may increase infection risk were more common among nursing-home personnel than hospital personnel, whereas selected factors outside the workplace were more common among hospital personnel.

Effectiveness of mRNA Covid-19 Vaccine among U.S. Health Care Personnel.

BACKGROUND: The prioritization of U.S. health care personnel for early receipt of messenger RNA (mRNA) vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (Covid-19), allowed for the evaluation of the effectiveness of these new vaccines in a real-world setting. METHODS: We conducted a test-negative case-control study involving health care personnel across 25 U.S. states. Cases were defined on the basis of a positive polymerase-chain-reaction (PCR) or antigen-based test for SARS-CoV-2 and at least one Covid-19-like symptom. Controls were defined on the basis of a negative PCR test for SARS-CoV-2, regardless of symptoms, and were matched to cases according to the week of the test date and site. Using conditional logistic regression with adjustment for age, race and ethnic group, underlying conditions, and exposures to persons with Covid-19, we estimated vaccine effectiveness for partial vaccination (assessed 14 days after receipt of the first dose through 6 days after receipt of the second dose) and complete vaccination (assessed ≥7 days after receipt of the second dose). RESULTS: The study included 1482 case participants and 3449 control participants. Vaccine effectiveness for partial vaccination was 77.6% (95% confidence interval [CI], 70.9 to 82.7) with the BNT162b2 vaccine (Pfizer-BioNTech) and 88.9% (95% CI, 78.7 to 94.2) with the mRNA-1273 vaccine (Moderna); for complete vaccination, vaccine effectiveness was 88.8% (95% CI, 84.6 to 91.8) and 96.3% (95% CI, 91.3 to 98.4), respectively. Vaccine effectiveness was similar in subgroups defined according to age (<50 years or ≥50 years), race and ethnic group, presence of underlying conditions, and level of patient contact. Estimates of vaccine effectiveness were lower during weeks 9 through 14 than during weeks 3 through 8 after receipt of the second dose, but confidence intervals overlapped widely. CONCLUSIONS: The BNT162b2 and mRNA-1273 vaccines were highly effective under real-world conditions in preventing symptomatic Covid-19 in health care personnel, including those at risk for severe Covid-19 and those in racial and ethnic groups that have been disproportionately affected by the pandemic. (Funded by the Centers for Disease Control and Prevention.).

Interim Estimates of Vaccine Effectiveness of Pfizer-BioNTech and Moderna COVID-19 Vaccines Among Health Care Personnel - 33 U.S. Sites, January-March 2021.

Throughout the COVID-19 pandemic, health care personnel (HCP) have been at high risk for exposure to SARS-CoV-2, the virus that causes COVID-19, through patient interactions and community exposure (1). The Advisory Committee on Immunization Practices recommended prioritization of HCP for COVID-19 vaccination to maintain provision of critical services and reduce spread of infection in health care settings (2). Early distribution of two mRNA COVID-19 vaccines (Pfizer-BioNTech and Moderna) to HCP allowed assessment of the effectiveness of these vaccines in a real-world setting. A test-negative case-control study is underway to evaluate mRNA COVID-19 vaccine effectiveness (VE) against symptomatic illness among HCP at 33 U.S. sites across 25 U.S. states. Interim analyses indicated that the VE of a single dose (measured 14 days after the first dose through 6 days after the second dose) was 82% (95% confidence interval [CI] = 74%-87%), adjusted for age, race/ethnicity, and underlying medical conditions. The adjusted VE of 2 doses (measured ≥7 days after the second dose) was 94% (95% CI = 87%-97%). VE of partial (1-dose) and complete (2-dose) vaccination in this population is comparable to that reported from clinical trials and recent observational studies, supporting the effectiveness of mRNA COVID-19 vaccines against symptomatic disease in adults, with strong 2-dose protection.

Increases in Human Papillomavirus Testing Preceding Diagnosis of Cervical Precancer in 5 US States, 2008-2016.

OBJECTIVE: The aim of the study was to describe trends in human papillomavirus (HPV) testing preceding diagnosis of cervical precancer during a time of changing screening recommendations. MATERIALS AND METHODS: We conducted a cross-sectional analysis of data from active, population-based, laboratory surveillance among 1.5 million residents of 5 areas in the United States. We included women aged 21-39 years diagnosed with cervical intraepithelial neoplasia grades 2, 2/3, or 3 or adenocarcinoma in situ (collectively, CIN2+) during 2008-2016, who had a cytology and/or HPV test before diagnosis (n = 16,359). RESULTS: The proportion of women with an HPV test preceding CIN2+ increased from 42.9% in 2008 to 73.3% in 2016 (p < .01); testing increased in all age groups (21-24 y: 35.3% to 47.6%, 25-29 y: 40.9% to 64.1%, 30-39 y: 51.7% to 85.9%, all p < .01). The HPV testing varied by cytology result and was highest among women with atypical squamous cells of unknown significance (n = 4,310/4,629, 93.1%), negative for intraepithelial lesion or malignancy (n = 446/517, 86.3%), and atypical glandular cells (n = 145/257, 56.4%). By 2016, at least half of all cases in every surveillance area had an HPV test before diagnosis. CONCLUSIONS: During 2008-2016, the proportion of women with an HPV test preceding CIN2+ increased significantly for all age groups, cytology results, and surveillance areas. By 2016, most (85.9%) women aged 30-39 years had an HPV test, consistent with recommendations. Increasing utilization of HPV tests, which have demonstrated improved sensitivity for detecting cervical disease, may in part explain increasing rates of cervical precancer among women 30 years and older.

Human Papillomavirus 16/18-Associated Cervical Lesions: Differences by Area-Based Measures of Race and Poverty.

INTRODUCTION: This analysis evaluates trends in cervical lesions with human papillomavirus 16/18 detected by area-based measures of race, ethnicity, and poverty during 2008-2015. METHODS: Trends in the proportion of lesions with human papillomavirus 16/18 detected among residents of New Haven County, Connecticut were examined by area-based measures of race, ethnicity, and poverty. Area-based measures are aggregate descriptors of census tract characteristics useful for measuring differences in health outcomes in the context of where people live. Multivariable logistic regression modeling was conducted, adjusted for individual-level race, ethnicity, and insurance status to assess the independent effects of area-based measures. Data were analyzed in 2018-2019. RESULTS: Among women aged 21-24 years and 25-29 years, significant declines in the proportion of lesions with human papillomavirus 16/18 were observed. Among women aged 21-24 years, declines began earlier and were greater in magnitude in areas of lower poverty (OR=0.55, 95% CI=0.36, 0.85 for 2010-2012 vs 2008-2009 and OR=0.30, 95% CI=0.18, 0.51 for 2013-2015 vs 2008-2009) compared with higher poverty (OR=1.66, 95% CI=0.86, 3.21 and OR=0.48, 95% CI=0.19, 1.20). Similar patterns were observed for women aged 25-29 years, and for area-based measures of race and ethnicity. CONCLUSIONS: Differences were observed in declines in the proportion of human papillomavirus 16/18 lesions by area-based measures since the introduction of human papillomavirus vaccines, with greater and earlier declines in areas with fewer residents living in poverty and racial minorities. Ongoing human papillomavirus vaccine impact monitoring is necessary to track differences by sociodemographic characteristics.

Missed Opportunities for HPV Vaccination Among Vaccine-Eligible Women with High Grade Cervical Lesions.

BACKGROUND: Incidence of high-grade cervical lesions (HGCL) has declined in the U.S following the introduction of the human papillomavirus (HPV) vaccine in 2006. However, many women continue to be diagnosed with HGCLs, including those eligible to receive the vaccine but did not. We determined self-reported barriers to and correlates of HPV vaccination in vaccine-eligible women diagnosed with cervical intraepithelial neoplasia grades 2, 2/3, 3 and adenocarcinoma in situ (CIN2+). METHODS: Data from a statewide surveillance system in Connecticut for CIN 2+ during 2008-2015 were used for this analysis. Enhanced surveillance data were collected for women residing in New Haven County, including HPV vaccine history and demographic factors, through chart review and patient interviews. Women who reported being unvaccinated were asked why they did not receive the vaccine. We evaluated trends in reasons for not receiving the vaccine using a two-sided Cochran Armitage trend test. Log-binomial analysis was used to assess associations between sociodemographic characteristics and vaccination status. RESULTS: Between 2008 and 2015, 1625 vaccine-eligible women were diagnosed with CIN2+, with 882 of these women reporting never receiving the HPV vaccine. The proportion of unvaccinated vaccine-eligible women did not significantly change from 2008 to 2015 (p = 0.18, range 49.1% to 60.0%). The most commonly reported reason for being unvaccinated was age/too old, followed by previous HPV diagnosis and no provider recommendation. Women who had public or no insurance were significantly more likely than privately insured women to report being unvaccinated (p = <0.001, p = 0.0034). CONCLUSIONS: Commonly cited barriers to vaccination, such as age/too old and previous HPV diagnosis, are not contraindications for vaccination. Furthermore, frequent reporting of no provider recommendation underscores the important role providers play in the immunization of their patients. These results indicate the need for greater efforts by providers to dispel myths about HPV vaccine eligibility and to promote vaccination for all of their eligible patients.

Estimated Number of Cases of High-Grade Cervical Lesions Diagnosed Among Women - United States, 2008 and 2016.

Human papillomavirus (HPV) causes approximately 30,000 cancers in the United States annually (1). HPV vaccination was introduced in 2006 to prevent HPV-associated cancers and diseases (1). Cervical cancer is the most common HPV-associated cancer in women (1). Whereas HPV-associated cancers typically take decades to develop, screen-detected high-grade cervical lesions (cervical intraepithelial neoplasia grades 2 [CIN2], 3 [CIN3], and adenocarcinoma in situ, collectively CIN2+) develop within a few years after infection and have been used to monitor HPV vaccine impact (1-3). CDC analyzed data from the Human Papillomavirus Vaccine Impact Monitoring Project (HPV-IMPACT), a population-based CIN2+ surveillance system, to describe rates of CIN2+ among women aged ≥18 years during 2008-2016. Age-specific rates were applied to U.S. population data to estimate the total number of CIN2+ cases diagnosed in the United States in 2008* and in 2016. From 2008 to 2016, the rate of CIN2+ per 100,000 women declined significantly in women aged 18-19 years and 20-24 years and increased significantly in women aged 40-64 years. In the United States in 2008, an estimated 216,000 (95% confidence interval [CI] = 194,000-241,000) CIN2+ cases were diagnosed, 55% of which were in women aged 18-29 years; in 2016, an estimated 196,000 (95% CI = 176,000-221,000) CIN2+ cases were diagnosed, 36% of which were in women aged 18-29 years. During 2008 and 2016, an estimated 76% of CIN2+ cases were attributable to HPV types targeted by the vaccine currently used in the United States. These estimates of CIN2+ cases likely reflect changes in CIN2+ detection resulting from updated cervical cancer screening and management recommendations, as well as primary prevention through HPV vaccination. Increasing coverage of HPV vaccination in females at the routine age of 11 or 12 years and catch-up vaccination through age 26 years will contribute to further reduction in cervical precancers.

Trends in High-grade Cervical Lesions and Cervical Cancer Screening in 5 States, 2008-2015.

BACKGROUND: We describe changes in rates of cervical intraepithelial neoplasia grades 2, 3 and adenocarcinoma in situ (CIN2+) during a period of human papillomavirus (HPV) vaccine uptake and changing cervical cancer screening recommendations. METHODS: We conducted population-based laboratory surveillance for CIN2+ in catchment areas in 5 states, 2008-2015. We calculated age-specific CIN2+ rates per 100000 women by age groups. We estimated incidence rate ratios (IRR) of CIN2+ for 2-year periods among all women and among screened women to evaluate changes over time. RESULTS: A total of 16572 CIN2+ cases were reported. Among women aged 18-20 and 21-24 years, CIN2+ rates declined in all sites, whereas in women aged 25-29, 30-34, and 35-39 years, trends differed across sites. The percent of women screened annually declined in all sites and age groups. Compared to 2008-2009, rates among screened women were significantly lower for all 3 periods in women aged 18-20 years (2010-2011: IRR 0.82, 95% confidence interval [CI] 0.67-0.99; 2012-2013: IRR 0.63, 95% CI 0.47-0.85; 2014-2015: IRR 0.44, 95% CI 0.28-0.68) and lower for the latter 2 time periods in women aged 21-24 years (2012-2013: IRR 0.86, 95% CI 0.79-0.94; 2014-2015: IRR 0.61, 95% CI 0.55-0.67). CONCLUSIONS: From 2008-2015, both CIN2+ rates and cervical cancer screening declined in women aged 18-24 years. The significant decreases in CIN2+ rates among screened women aged 18-24 years are consistent with a population-level impact of HPV vaccination.

Declines in Human Papillomavirus (HPV)-Associated High-Grade Cervical Lesions After Introduction of HPV Vaccines in Connecticut, United States, 2008-2015.

BACKGROUND: Trends in human papillomavirus (HPV)-associated cervical lesions can provide an indication of vaccine impact. Our purpose was to measure trends in cervical lesions during 2008-2015 and to consider possible explanations including vaccination coverage, changes in screening for cervical cancer, and risk behaviors for acquiring HPV. METHODS: Connecticut (CT) implemented mandatory reporting of cervical intraepithelial neoplasia grades 2/3 and adenocarcinoma in situ (cervical intraepithelial neoplasia grade 2 or higher [CIN2+]) in 2008. Trends by age and birth cohort were modeled using negative binomial regression and change-point methods. To evaluate possible explanations for changes, these trends were compared to changes in HPV vaccination coverage, cervical cancer screening, an antecedent event to detection of a high-grade lesion, and changes in sexual behaviors and Chlamydia trachomatis, an infection with similar epidemiology to and shared risk factors for HPV. RESULTS: A significant decline in CIN2+ was first evident among women aged 21 years in 2010, followed by successive declines in women aged 22-26 years during 2011-2012. During 2008-2015, the rates of CIN2+ declined by 30%-74% among women aged 21-26 years, with greater declines observed in the younger women. Birth cohorts between 1985 and 1994 all experienced significant declines during the surveillance period, ranging from 25% to 82%. Ecological comparisons revealed substantial increases in HPV vaccination during this time period, and more modest reductions in cervical cancer screening and sexual risk behaviors. CONCLUSIONS: The age and cohort patterns in our data suggest that declines in CIN2+ during 2008-2015 are more likely driven by HPV vaccination, introduced in 2006, than by changes in screening or risk behavior.

Passive multistate surveillance for neutropenia after use of cocaine or heroin possibly contaminated with levamisole.

STUDY OBJECTIVE: To characterize the demographic, clinical, and epidemiologic features of levamisole-associated neutropenia in cocaine or heroin users. METHODS: State health departments were recruited for participation when the Centers for Disease Control and Prevention (CDC) was notified of potential cases by a clinician, a health department official, or a poison center between October 15, 2009, and May 31, 2010. A case was defined as a person with an absolute neutrophil count less than 1,000 cells/µL (or a WBC count <2,000 cells/µL) and a self-reported history or laboratory confirmation of cocaine or heroin use. Health department officials abstracted data from medical charts, attempted a patient interview, and submitted data to CDC for descriptive analysis. RESULTS: Of the 46 potential cases reported from 6 states, half met eligibility criteria and had medical chart abstractions completed (n=23; 50%). Of these, close to half of the patients were interviewed (n=10; 43%). The average age was 44.4 years; just over half were men (n=12; 52%). The majority of patients presented to emergency departments (n=19; 83%). More than half presented with infectious illnesses (n=12; 52%), and nearly half reported active skin lesions (n=10; 44%). The majority of interview respondents used cocaine greater than 2 to 3 times a week (n=9; 90%), used cocaine more than 2 years (n=6; 60%), and preferred crack cocaine (n=6; 60%). All were unaware of exposure to levamisole through cocaine and of levamisole's inherent toxicity (n=10; 100%). CONCLUSION: Physicians should suspect levamisole exposure in patients using illicit drugs, cocaine in particular, who present with unexplained neutropenia. Most patients reported chronic cocaine use and were unaware of levamisole exposure. Cocaine use is more prevalent among men; however, our results identified a higher-than-expected proportion of female users with neutropenia, suggesting women may be at higher risk. Emergency physicians and practitioners are uniquely positioned to recognize these patients early during their hospital course, elucidate a history of cocaine or other drug exposure, and optimize the likelihood of confirming exposure by arranging for appropriate drug testing.

Clinicopathologic features of agranulocytosis in the setting of levamisole-tainted cocaine.

Levamisole is a known contaminant of cocaine and, via this route, has been associated with otherwise unexplained agranulocytosis. Levamisole is currently present in the majority of cocaine samples seized by the US Drug Enforcement Agency. We identified 20 cases of unexplained agranulocytosis in our practice locations of Albuquerque, NM, and Vancouver, Canada. Epidemiologic investigation revealed recent or ongoing cocaine use in 14 cases (70%). Certain morphologic features, including circulating plasmacytoid lymphocytes, increased bone marrow plasma cells, and mild megakaryocytic hyperplasia, were associated with the cocaine-exposed group. Of 5 patients tested, 3 (60%) were HLA-B27+ and showed antineutrophil antibodies, consistent with known associations of levamisole-induced agranulocytosis. One patient, who was positive for cocaine and levamisole by toxicology testing, died of infectious complications. Inadvertent consumption of levamisole via cocaine is a severely under-appreciated risk factor for agranulocytosis, and specific laboratory features are suggestive of this etiology.

Epidemiology of Colorado tick fever in Montana, Utah, and Wyoming, 1995-2003.

Colorado tick fever (CTF) is a biphasic, febrile illness caused by a Coltivirus and transmitted by the Rocky Mountain wood tick, Dermacentor andersoni, in the western United States and Canada. Symptoms generally include acute onset of fever, headache, chills, and myalgias; illness often lasts for 3 weeks or more. Laboratory-confirmed cases of CTF were identified from public health department records in Montana, Utah, and Wyoming, and from the Centers for Disease Control and Prevention diagnostic laboratory records. Additional descriptive epidemiologic data were obtained by medical record abstraction. Ninety-one cases were identified from 1995 to 2003, resulting in an overall annual incidence of 2.7 per 1,000,000 population. The annual incidence decreased over the 9-year study period. Cases were 2.5 times more frequent in males than females. The highest incidence of cases occurred in persons aged 51-70. Tick exposure prior to illness onset was reported in 90% of the cases in which a more detailed history was available. The most common symptoms were fever, headache, and myalgia; 18% of the case patients were hospitalized. While there has been an overall decline in the recognized incidence of CTF cases, the reasons for the decline are unknown. Possibilities include a reduced intensity of surveillance and a true decrease in incidence. As more people continue to visit, move to and work in endemic areas, CTF should be considered in anyone presenting with a febrile illness following tick exposure in an endemic area. Heightened awareness for the disease and tick prevention messages should be part of public health measures to further decrease the incidence of disease.