Cluster of non-toxigenic Corynebacterium diphtheriae infective endocarditis and rising background C. diphtheriae cases-Seattle, Washington 2020-2023.

BACKGROUND: Non-toxigenic Corynebacterium diphtheriae (C. diphtheriae), often associated with wounds, can rarely cause infective endocarditis (IE). Five patients with C. diphtheriae IE were identified within 12 months at a Seattle-based hospital system. We reviewed prior C. diphtheriae positive cultures to determine if detections had increased over time and evaluated epidemiologic trends. METHODS: We conducted a formal electronic health record search to identify all patients ≥ 18 years of age with C. diphtheriae detected in a clinical specimen (i.e. wound, blood, sputum) between September 1, 2020-April 1, 2023. We collected patient demographics, housing status, comorbidities, substance use history and level of medical care required at detection. We extracted laboratory data on susceptibilities of C. diphtheriae isolates, and on other pathogens detected at the time of C. diphtheriae identification. RESULTS: Between September 1, 2020-April 1, 2023, 44 patients (median age 44 years) had a C. diphtheriae-positive clinical culture, with most detections occurring after March 2022. Patients were predominantly male (75%), White (66%), unstably housed (77%), and had a lifetime history of injecting drugs (75%). Most C. diphtheriae positive cultures were polymicrobial, including wound cultures from 36 (82%) patients and blood cultures from 6 (14%) patients, not mutually exclusive. Thirty-four patients (77%), including all five patients with C. diphtheriae IE, required hospital admission for C. diphtheriae or a related condition. Of the five patients with IE, three died of IE and one from COVID-19. CONCLUSION: Findings suggest a high-morbidity outbreak disproportionately affecting patients who use substances and are unstably housed.

Repeated introductions and intensive community transmission fueled a mumps virus outbreak in Washington State.

In 2016/2017, Washington State experienced a mumps outbreak despite high childhood vaccination rates, with cases more frequently detected among school-aged children and members of the Marshallese community. We sequenced 166 mumps virus genomes collected in Washington and other US states, and traced mumps introductions and transmission within Washington. We uncover that mumps was introduced into Washington approximately 13 times, primarily from Arkansas, sparking multiple co-circulating transmission chains. Although age and vaccination status may have impacted transmission, our data set could not quantify their precise effects. Instead, the outbreak in Washington was overwhelmingly sustained by transmission within the Marshallese community. Our findings underscore the utility of genomic data to clarify epidemiologic factors driving transmission and pinpoint contact networks as critical for mumps transmission. These results imply that contact structures and historic disparities may leave populations at increased risk for respiratory virus disease even when a vaccine is effective and widely used.

Societal Costs of a Measles Outbreak.

BACKGROUND AND OBJECTIVES: Between December 31, 2018, and April 26, 2019, 72 confirmed cases of measles were identified in Clark County. Our objective was to estimate the economic burden of the measles outbreak from a societal perspective, including public health response costs as well as direct medical costs and productivity losses of affected individuals. METHODS: To estimate costs related to this outbreak from the societal perspective, 3 types of costs were collected or estimated: public health response (labor, material, and contractor costs used to contain the outbreak), direct medical (third party or patient out-of-pocket treatment costs of infected individuals), and productivity losses (costs of lost productivity due to illness, home isolation, quarantine, or informal caregiving). RESULTS: The overall societal cost of the 2019 Clark County measles outbreak was ∼$3.4 million ($47 479 per case or $814 per contact). The majority of the costs (∼$2.3 million) were incurred by the public health response to the outbreak, followed by productivity losses (∼$1.0 million) and direct medical costs (∼$76 000). CONCLUSIONS: Recent increases in incident measles cases in the United States and across the globe underscore the need to more fully understand the societal cost of measles cases and outbreaks and economic consequences of undervaccination. Our estimates can provide valuable inputs for policy makers and public health stakeholders as they consider budget determinations and the substantial value associated with increasing vaccine coverage and outbreak preparedness as well as the protection of society against vaccine-preventable diseases, such as measles, which are readily preventable with high vaccination coverage.

Genomic epidemiology of nontoxigenic Corynebacterium diphtheriae from King County, Washington State, USA between July 2018 and May 2019.

Between July 2018 and May 2019, Corynebacterium diphtheriae was isolated from eight patients with non-respiratory infections, seven of whom experienced homelessness and had stayed at shelters in King County, WA, USA. All isolates were microbiologically identified as nontoxigenic C. diphtheriae biovar mitis. Whole-genome sequencing confirmed that all case isolates were genetically related, associated with sequence type 445 and differing by fewer than 24 single-nucleotide polymorphisms (SNPs). Compared to publicly available C. diphtheriae genomic data, these WA isolates formed a discrete cluster with SNP variation consistent with previously reported outbreaks. Virulence-related gene content variation within the highly related WA cluster isolates was also observed. These results indicated that genome characterization can readily support epidemiology of nontoxigenic C. diphtheriae.

Human Prion Disease Surveillance in Washington State, 2006-2017.

Importance: Human prion disease surveillance is critical to detect possible cases of variant Creutzfeldt-Jakob disease and other acquired forms of prion disease in the United States. Results are presented here that describe 12 years of surveillance in Washington, the only US state that has reported the presence of classic bovine spongiform encephalopathy, an animal prion disease that has been shown to transmit to humans. Objective: To describe the current prion disease surveillance system in Washington and the epidemiological and clinical results of surveillance from 2006 through 2017. Design, Setting, and Participants: This cross-sectional study reports findings from the human prion disease surveillance system in place in Washington state from January 1, 2006, through December 31, 2017. Participants included Washington residents with a clinical suspicion of human prion disease or suggestive test results from the National Prion Disease Pathology Surveillance Center or with prion disease listed as a cause of death on the death certificate. Data for this report were analyzed from June 1, 2016, to July 1, 2020. Exposure: Human prion disease diagnosis. Main Outcomes and Measures: The main outcome was incidence of human prion disease cases, including identification of variant Creutzfeldt-Jakob disease. Results: A total of 143 human prion disease cases were detected during the study period, none of which met criteria for a variant Creutzfeldt-Jakob disease diagnosis. Among 137 definite or probable cases, 123 (89.8%) occurred in persons aged 55 years or older, with a median age at death of 66 years (range, 38-84 years). Most patients were White (124 [92.5%] among 134 with reported race), and slightly over half were male (70 [51.1%]). The average annual age-adjusted prion disease incidence was 1.5 per million population per year, slightly higher than the national rate of 1.2 per million. A total of 99 cases (69.2%) were confirmed by neuropathology. Sporadic prion disease was the most common diagnosis, in 134 cases (93.7%), followed by familial prion disease in 8 cases (5.6%). One iatrogenic prion disease case (0.7%) was also reported. Conclusions and Relevance: The findings of this cross-sectional study suggest that demographic characteristics of patients with prion disease in Washington are consistent with national findings. The slightly higher incidence rate may be due to the state's enhanced surveillance activities, including close collaboration with key partners and educational efforts targeted toward health care providers. Results indicate that surveillance will continue to be beneficial for monitoring epidemiological trends, facilitating accurate diagnoses, and detecting variant Creutzfeldt-Jakob disease or other emerging human prion disease cases.

Investigation and Serologic Follow-Up of Contacts of an Early Confirmed Case-Patient with COVID-19, Washington, USA.

We describe the contact investigation for an early confirmed case of coronavirus disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in the United States. Contacts of the case-patient were identified, actively monitored for symptoms, interviewed for a detailed exposure history, and tested for SARS-CoV-2 infection by real-time reverse transcription PCR (rRT-PCR) and ELISA. Fifty contacts were identified and 38 (76%) were interviewed, of whom 11 (29%) reported unprotected face-to-face interaction with the case-patient. Thirty-seven (74%) had respiratory specimens tested by rRT-PCR, and all tested negative. Twenty-three (46%) had ELISA performed on serum samples collected ≈6 weeks after exposure, and none had detectable antibodies to SARS-CoV-2. Among contacts who were tested, no secondary transmission was identified in this investigation, despite unprotected close interactions with the infectious case-patient.

First Case of 2019 Novel Coronavirus in the United States.

An outbreak of novel coronavirus (2019-nCoV) that began in Wuhan, China, has spread rapidly, with cases now confirmed in multiple countries. We report the first case of 2019-nCoV infection confirmed in the United States and describe the identification, diagnosis, clinical course, and management of the case, including the patient's initial mild symptoms at presentation with progression to pneumonia on day 9 of illness. This case highlights the importance of close coordination between clinicians and public health authorities at the local, state, and federal levels, as well as the need for rapid dissemination of clinical information related to the care of patients with this emerging infection.

Cost of Responding to the 2017 University of Washington Mumps Outbreak: A Prospective Analysis.

OBJECTIVES: To estimate costs of labor and materials by the University of Washington (UW) and state and local public health departments (PHDs) to respond to the February to June 2017 UW mumps outbreak, where 42 cases were identified among students (primarily sorority and fraternity members), staff, and associated community members. DESIGN: We applied standard cost analysis methodology using a combined public health and university perspective to examine the cost of responding to the outbreak. SETTING: UW's Seattle campus encompasses 703 acres with approximately 32 000 undergraduate students. Nearly 15% of the undergraduate population are members of fraternities or sororities. Housing for the fraternities and sororities is adjacent to the UW campus and consists of 50 houses. PARTICIPANTS: During the outbreak, customized costing tools based on relevant staff or faculty positions and activities were provided to the UW and Public Health-Seattle & King County, populated by each person participating in the outbreak response, and then collected and analyzed. Laboratory hours and material costs were collected from the Washington Department of Health and the Minnesota Department of Health. MAIN OUTCOME MEASURE: Labor and material costs provided by the UW and PHDs during the outbreak were collected and categorized by payer and activity. RESULTS: Total costs to the UW and PHDs in responding to the outbreak were $282 762 ($6692 per case). Of these, the UW spent $160 064, while PHDs spent $122 098. Labor accounted for 77% of total outbreak costs, and UW response planning and coordination accounted for the largest amount of labor costs ($75 493) overall. CONCLUSIONS: Given the current university and public health department budget constraints, the response to the outbreak amounted to a significant use of resources. Labor was the largest driver of costs for the outbreak response; UW labor costs-related to campus response planning and coordination-dominated the total economic burden from public health and university perspectives.

Health Departments' Experience With Mumps Outbreak Response and Use of a Third Dose of Measles, Mumps, and Rubella Vaccine.

CONTEXT: During January 2016 to June 2017, US health departments (HDs) reported 150 mumps outbreaks. Most occurred among populations with high 2-dose measles, mumps, and rubella (MMR) vaccine coverage, prompting the Advisory Committee on Immunization Practices to examine the evidence for use of a third dose of MMR vaccine. OBJECTIVE: To evaluate HD experiences with mumps outbreak control and use of a third MMR dose during outbreaks. DESIGN: An online survey assessing mumps outbreak characteristics, outbreak response measures, challenges, and lessons learned from previous outbreaks was distributed to all 81 Council of State and Territorial Epidemiologists member HDs in August 2017. RESULTS: Sixty-one (75%) HDs responded; 46 (75%) had experience with ≥1 mumps outbreak(s) during January 2016 to August 2017. Twenty (43%) HDs recommended a third or outbreak MMR dose during mumps outbreaks; of these, 19 completed the section on use of a third dose and 8 (40%) rated the intervention "somewhat effective" or better. Health departments that used a third/outbreak dose suggested implementing the recommendation early and to a targeted group. Forty-three (73%) HDs reported having a policy for excluding persons without presumptive immunity from outbreak settings; of these, 37 (86%) had some degree of legal authority to implement this policy. Exclusion compliance improved with the use of personalized notification letters, focus groups of excluded persons and the community, and standardized messaging. Other outbreak control measures included cohorting of exposed or susceptible persons, mobile vaccination clinics and home visits, contact monitoring via text messaging, and facilitating student isolation with meal delivery and excused class absences. CONCLUSIONS: Our study revealed heterogeneity across HDs' mumps outbreak responses but also identified common challenges that will inform future Centers for Disease Control and Prevention guidance. These results were considered in the October 2017 Advisory Committee on Immunization Practices recommendation for use of a third dose of MMR vaccine for persons at increased risk for mumps during an outbreak and in the development of Centers for Disease Control and Prevention guidance for HDs when applying the Advisory Committee on Immunization Practices recommendation.

Imported Toxin-Producing Cutaneous Diphtheria - Minnesota, Washington, and New Mexico, 2015-2018.

From September 2015 to March 2018, CDC confirmed four cases of cutaneous diphtheria caused by toxin-producing Corynebacterium diphtheriae in patients from Minnesota (two), Washington (one), and New Mexico (one). All patients had recently returned to the United States after travel to countries where diphtheria is endemic. C. diphtheriae infection was not clinically suspected in any of the patients; treating institutions detected the organism through matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF) testing of wound-derived coryneform isolates. MALDI-TOF is a rapid screening platform that uses mass spectrometry to identify bacterial pathogens. State public health laboratories confirmed C. diphtheriae through culture and sent isolates to CDC's Pertussis and Diphtheria Laboratory for biotyping, polymerase chain reaction (PCR) testing, and toxin production testing. All isolates were identified as toxin-producing C. diphtheriae. The recommended public health response for cutaneous diphtheria is similar to that for respiratory diphtheria and includes treating the index patient with antibiotics, identifying close contacts and observing them for development of diphtheria, providing chemoprophylaxis to close contacts, testing patients and close contacts for C. diphtheriae carriage in the nose and throat, and providing diphtheria toxoid-containing vaccine to incompletely immunized patients and close contacts. This report summarizes the patient clinical information and response efforts conducted by the Minnesota, Washington, and New Mexico state health departments and CDC and emphasizes that health care providers should consider cutaneous diphtheria as a diagnosis in travelers with wound infections who have returned from countries with endemic diphtheria.

Public health responses during measles outbreaks in elimination settings: Strategies and challenges.

In late September 2016, the Americas became the first region in the world to have eliminated endemic transmission of measles virus. Several other countries have also verified measles elimination, and countries in all six World Health Organization regions have adopted measles elimination goals. The public health strategies used to respond to measles outbreaks in elimination settings are thus becoming relevant to more countries. This review highlights the strategies used to limit measles spread in elimination settings: (1) assembly of an outbreak control committee; (2) isolation of measles cases while infectious; (3) exclusion and quarantining of individuals without evidence of immunity; (4) vaccination of susceptible individuals; (5) use of immunoglobulin to prevent measles in exposed susceptible high-risk persons; (6) and maintaining laboratory proficiency for confirmation of measles. Deciding on the extent of containment efforts should be based on the expected benefit of reactive interventions, balanced against the logistical challenges in implementing them.

Acute Flaccid Myelitis Among Children - Washington, September-November 2016.

In October 2016, Seattle Children's Hospital notified the Washington State Department of Health (DOH) and CDC of a cluster of acute onset of limb weakness in children aged ≤14 years. All patients had distinctive spinal lesions largely restricted to gray matter detected by magnetic resonance imaging (MRI), consistent with acute flaccid myelitis (AFM). On November 3, DOH issued a health advisory to local health jurisdictions requesting that health care providers report similar cases. By January 24, 2017, DOH and CDC had confirmed 10 cases of AFM and excluded two suspected cases among residents of Washington during September-November 2016. Upper respiratory tract, stool, rectal, serum, buccal, and cerebrospinal fluid (CSF) specimens were tested for multiple pathogens. Hypothesis-generating interviews were conducted with patients or their parents to determine commonalities between cases. No common etiology or source of exposure was identified. Polymerase chain reaction (PCR) testing detected enterovirus D68 (EV-D68) in nasopharyngeal swabs of two patients, one of whom also tested positive for adenovirus by PCR, and detected enterovirus A71 (EV-A71) in the stool of a third patient. Mycoplasma spp. immunoglobulin M (IgM) titer was elevated in two patients, but both had upper respiratory swabs that tested negative for Mycoplasma spp. by PCR. Clinicians should maintain vigilance for AFM and report cases as soon as possible to state or local health departments.

Risk Factors Associated With Bordetella pertussis Among Infants ≤4 Months of Age in the Pre-Tdap Era: United States, 2002-2005.

BACKGROUND: In the United States, infants have the highest reported pertussis incidence and death rates. Improved understanding of infant risk factors is needed to optimize prevention strategies. METHODS: We prospectively enrolled infants ≤4 months of age with incident-confirmed pertussis from 4 sites during 2002-2005 (preceding pertussis antigen-containing vaccination recommendations for adolescents/adults); each case-patient was age and site matched with 2 control subjects. Caregivers completed structured interviews. Infants and their contacts ≥11 years of age were offered serologic testing for IgG; being seropositive was defined as ≥94 antipertussis toxin IgG enzyme-linked immunosorbent assay units per milliliter. RESULTS: Enrolled subjects (115 case-patients; 230 control subjects) had 4396 contacts during incubation periods; 83 (72%) case-patients had ≥1 contact with prolonged (≥5 days) new cough in primary or secondary households. In multivariable analysis, the odds for pertussis were higher for infants with primary/secondary household contacts who had a prolonged new cough, compared with infants who did not. These contacts included mother [adjusted matched odds ratio (aMOR), 43.8; 95% confidence interval (CI), 6.45-298.0] and ≥1 nonmother contact (aMOR, 20.1; 95% CI, 6.48-62.7). Infants receiving breast milk with 0-1 formula feedings daily had decreased pertussis odds (aMOR, 0.27; 95% CI, 0.08-0.89), compared with those receiving more formula. Of 41 tested case-patients, 37 (90%) were seropositive. CONCLUSIONS: Pertussis in infants was associated with prolonged new cough (≥5 days) in infants' household contacts. Findings suggest that breastfeeding protects against pertussis and warrants recommendation with pertussis prevention strategies, which currently include pertussis vaccination of pregnant mothers and infants' close contacts.

Parental Country of Birth and Childhood Vaccination Uptake in Washington State.

BACKGROUND: Underimmunization of certain immigrant populations can place them at high risk of experiencing vaccine-preventable disease outbreaks. METHODS: We conducted a retrospective cohort study between January 1, 2008, and May 1, 2013, among children included in the Washington State Immunization Information System. We assessed receipt of 1 or more doses of measles-containing, hepatitis A, pneumococcal, and diphtheria-tetanus-acellular pertussis-containing vaccines between 12 and 23 months of age. We compared children with 1 or more parents born in Somalia, Ukraine, Russia, Mexico, or India to children with 2 parents born in the United States. Poisson regression models with robust SEs were used to provide prevalence ratios adjusted for maternal education and number of prenatal visits. RESULTS: We identified 277 098 children, including 65 466 with foreign-born parents. Children of Somali-born parents were less likely to be immunized against measles than children of US-born parents (prevalence ratio: 0.82; 95% confidence interval: 0.80-0.84); this decrease became more pronounced over time (P < .01). No such disparity between these groups was observed with other vaccines. Compared with children of US-born parents, children of Ukrainian-born and Russian-born parents were less likely to be immunized, whereas children of Mexican-born and Indian-born parents were more likely to be immunized with any of the specified vaccines. CONCLUSIONS: We found country-specific patterns of immunization that may reflect underlying cultural or other beliefs. Certain immigrant communities with higher rates of immunization refusal may be at risk for vaccine-preventable diseases and require new forms of public health outreach.

Tdap vaccine effectiveness in adolescents during the 2012 Washington State pertussis epidemic.

BACKGROUND: Acellular pertussis vaccines replaced whole-cell vaccines for the 5-dose childhood vaccination series in 1997. A sixth dose of pertussis-containing vaccine, tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis, adsorbed (Tdap), was recommended in 2005 for adolescents and adults. Studies examining Tdap vaccine effectiveness (VE) among adolescents who have received all acellular vaccines are limited. METHODS: To assess Tdap VE and duration of protection, we conducted a matched case-control study during the 2012 pertussis epidemic in Washington among adolescents born during 1993-2000. All pertussis cases reported from January 1 through June 30, 2012, in 7 counties were included; 3 controls were matched by primary provider clinic and birth year to each case. Vaccination histories were obtained through medical records, the state immunization registry, and parent interviews. Participants were classified by type of pertussis vaccine received on the basis of birth year: a mix of whole-cell and acellular vaccines (1993-1997) or all acellular vaccines (1998-2000). We used conditional logistic regression to calculate odds ratios comparing Tdap receipt between cases and controls. RESULTS: Among adolescents who received all acellular vaccines (450 cases, 1246 controls), overall Tdap VE was 63.9% (95% confidence interval [CI]: 50% to 74%). VE within 1 year of vaccination was 73% (95% CI: 60% to 82%). At 2 to 4 years postvaccination, VE declined to 34% (95% CI: -0.03% to 58%). CONCLUSIONS: Tdap protection wanes within 2 to 4 years. Lack of long-term protection after vaccination is likely contributing to increases in pertussis among adolescents.

Pertactin-negative Bordetella pertussis strains: evidence for a possible selective advantage.

BACKGROUND: A recent increase in Bordetella pertussis without the pertactin protein, an acellular vaccine immunogen, has been reported in the United States. Determining whether pertactin-deficient (PRN(-)) B. pertussis is evading vaccine-induced immunity or altering the severity of illness is needed. METHODS: We retrospectively assessed for associations between pertactin production and both clinical presentation and vaccine history. Cases with isolates collected between May 2011 and February 2013 from 8 states were included. We calculated unadjusted and adjusted odds ratios (ORs) using multivariable logistic regression analysis. RESULTS: Among 753 isolates, 640 (85%) were PRN(-). The age distribution differed between cases caused by PRN(-) B. pertussis and cases caused by B. pertussis producing pertactin (PRN(+)) (P = .01). The proportion reporting individual pertussis symptoms was similar between the 2 groups, except a higher proportion of PRN(+) case-patients reported apnea (P = .005). Twenty-two case-patients were hospitalized; 6% in the PRN(+) group compared to 3% in the PRN(-) group (P = .11). Case-patients having received at least 1 pertussis vaccine dose had a higher odds of having PRN(-) B. pertussis compared with unvaccinated case-patients (adjusted OR = 2.2; 95% confidence interval [CI], 1.3-4.0). When restricted to case-patients at least 1 year of age and those age-appropriately vaccinated, the adjusted OR increased to 2.7 (95% CI, 1.2-6.1). CONCLUSIONS: The significant association between vaccination and isolate pertactin production suggests that the likelihood of having reported disease caused by PRN(-) compared with PRN(+) strains is greater in vaccinated persons. Additional studies are needed to assess whether vaccine effectiveness is diminished against PRN(-) strains.

Molecular epidemiology of the pertussis epidemic in Washington State in 2012.

Although pertussis disease is vaccine preventable, Washington State experienced a substantial rise in pertussis incidence beginning in 2011. By June 2012, the reported cases reached 2,520 (37.5 cases per 100,000 residents), a 1,300% increase compared with the same period in 2011. We assessed the molecular epidemiology of this statewide epidemic using 240 isolates collected from case patients reported from 19 of 39 Washington counties during 2012 to 2013. The typing methods included pulsed-field gel electrophoresis (PFGE), multilocus variable number tandem repeat analysis (MLVA), multilocus sequence typing (MLST), and pertactin gene (prn) mutational analysis. Using the scheme PFGE-MLVA-MLST-prn mutations-Prn deficiency, the 240 isolates comprised 65 distinct typing profiles. Thirty-one PFGE types were found, with the most common types, CDC013 (n = 51), CDC237 (n = 44), and CDC002 (n = 42), accounting for 57% of them. Eleven MLVA types were observed, mainly comprising type 27 (n = 183, 76%). Seven MLST types were identified, with the majority of the isolates typing as prn2-ptxP3-ptxA1-fim3-1 (n = 157, 65%). Four different prn mutations accounted for the 76% of isolates exhibiting pertactin deficiency. PFGE provided the highest discriminatory power (D = 0.87) and was found to be a more powerful typing method than MLVA and MLST combined (D = 0.67). This study provides evidence for the continued predominance of MLVA 27 and prn2-ptxP3-ptxA1 alleles, along with the reemergence of the fim3-1 allele. Our results indicate that the Bordetella pertussis population causing this epidemic was diverse, with a few molecular types predominating. The PFGE, MLVA, and MLST profiles were consistent with the predominate types circulating in the United States and other countries. For prn, several mutations were present in multiple molecular types.