Paul R. Cieslak

Epidemiology of Invasive Group A Streptococcal Infections in the United States, 2005–2012

BACKGROUNDnInvasive group A Streptococcus (GAS) infections are associated with significant morbidity and mortality rates. We report the epidemiology and trends of invasive GAS over 8 years of surveillance.nnnMETHODSnFrom January 2005 through December 2012, we collected data from the Centers for Disease Control and Preventions Active Bacterial Core surveillance, a population-based network of 10 geographically diverse US sites (2012 population, 32.8 million). We defined invasive GAS as isolation of GAS from a normally sterile site or from a wound in a patient with necrotizing fasciitis (NF) or streptococcal toxic shock syndrome (STSS). Available isolates were emm typed. We calculated rates and made age- and race-adjusted national projections using census data.nnnRESULTSnWe identified 9557 cases (3.8 cases per 100 000 persons per year) with 1116 deaths (case-fatality rate, 11.7%). The case-fatality rates for septic shock, STSS, and NF were 45%, 38%, and 29%, respectively. The annual incidence was highest among persons aged ≥65 years (9.4/100 000) or <1 year (5.3) and among blacks (4.7/100 000). National rates remained steady over 8 years of surveillance. Factors independently associated with death included increasing age, residence in a nursing home, recent surgery, septic shock, NF, meningitis, isolated bacteremia, pneumonia, emm type 1 or 3, and underlying chronic illness or immunosuppression. An estimated 10 649-13 434 cases of invasive GAS infections occur in the United States annually, resulting in 1136-1607 deaths. In a 30-valent M-protein vaccine, emm types accounted for 91% of isolates.nnnCONCLUSIONSnThe burden of invasive GAS infection in the United States remains substantial. Vaccines under development could have a considerable public health impact.

Vaccinated Children and Adolescents With Pertussis Infections Experience Reduced Illness Severity and Duration, Oregon, 2010–2012

BACKGROUNDnBordetella pertussis causes severe respiratory illness among infants and adolescents. High proportions of breakthrough infection have been observed. To understand the effect of vaccination in the era of acellular pertussis vaccines (DTaP and Tdap), we assessed if vaccination status is associated with disease severity and duration.nnnMETHODSnThe Multnomah County Health Department conducts enhanced pertussis surveillance for 1.7 million residents in the Portland, Oregon, metropolitan area. Surveillance activities include ascertaining demographics, clinical presentation, cough duration, vaccination history, and other health outcomes. Utilizing Advisory Committee on Immunization Practices (ACIP) routine vaccination recommendations, we analyzed a cohort of persons aged 6 weeks to 18 years with confirmed pertussis to assess illness severity and duration by vaccination status. Analysis was conducted using both logistic regression (disease severity) and survival analysis (cough duration).nnnRESULTSnDuring 2010-2012, 98.7% (n = 624) of patients with confirmed pertussis in our cohort had vaccination, treatment, demographic, and outcome information. Among these patients, 45% (n = 286) were ACIP up to date with vaccinations. Ever-vaccinated cases were significantly less likely to be hospitalized or develop severe illness (adjusted odds ratio [aOR], 0.2; 95% confidence interval [CI], .1-.8 and aOR, 0.4; 95% CI, .2-.9, respectively). ACIP up-to-date patients stopped coughing significantly more rapidly than unvaccinated patients (adjusted hazard ratio, 1.7; 95% CI, 1.3-2.2).nnnCONCLUSIONSnPatients with pertussis vaccination had decreased morbidity characterized by less severe illness and significantly reduced illness duration. Therefore, vaccination is recommended among at-risk individuals, and research into the nature of the residual vaccine immunity is warranted.

Epidemiologic, Virologic, and Host Genetic Factors of Norovirus Outbreaks in Long-term Care Facilities

BACKGROUNDnIn the Unites States, long-term care facilities (LTCFs) are the most common setting for norovirus outbreaks. These outbreaks provide a unique opportunity to better characterize the viral and host characteristics of norovirus disease.nnnMETHODSnWe enrolled 43 LTCFs prospectively to study the epidemiology, virology, and genetic host factors of naturally occurring norovirus outbreaks. Acute and convalescent stool, serum, and saliva samples from cases, exposed and nonexposed controls were collected. Norovirus infection was confirmed using quantitative polymerase chain reaction testing of stool samples or 4-fold increase in serum antibody titers. The presence of histo-blood group antigens (secretor, ABO, and Lewis type) was determined in saliva.nnnRESULTSnSixty-two cases, 34 exposed controls, and 18 nonexposed controls from 10 norovirus outbreaks were enrolled. Forty-six percent of acute, 27% of convalescent case, and 11% of control stool samples tested norovirus positive. Outbreak genotypes were GII.4 (Den Haag, n = 3; New Orleans, n = 4; and Sydney, n = 2) and GI.1 (n = 1). Viral load in GII.4 Sydney outbreaks was significantly higher than in outbreaks caused by other genotypes; cases and controls shed similar amounts of virus. Forty-seven percent of cases shed virus for ≥ 21 days. Symptomatic infections with GII.4 Den Haag and GII.4 New Orleans were detected among nonsecretor individuals.nnnCONCLUSIONSnAlmost half of all symptomatic individuals shed virus for at least 21 days. Viral load was highest in GII.4 viruses that most recently emerged; these viruses also infect the nonsecretor population. These findings will help to guide development of targeted prevention and control measures in the elderly.

Pertussis vaccine performance in an epidemic year — Oregon, 2012

A 2012 pertussis epidemic in Oregon afforded an opportunity to measure vaccine effectiveness; it ranged from 95% (95% confidence interval [CI], 92%-97%) among children 15-47 months of age to 47% (95% CI, 19%-65%) among adolescents 13-16 years of age. In all age groups, pertussis incidence was higher among unimmunized persons.

Cryptococcus gattii infection in solid organ transplant recipients: description of Oregon outbreak cases

Cryptococcus gattii was recognized as an emerging infection in the Pacific Northwest in 2004. Out of 62 total infections in Oregon since the outbreak, 11 were in solid organ transplant (SOT) recipients. SOT recipients were more likely to have disseminated disease and higher mortality than normal hosts, who mostly had isolated mass lesions. The median time from transplantation to C. gattii diagnosis was 17.8 months. The primary sites of infection were lung (n = 4), central nervous system (n = 3), or both (n = 4). The Oregon‐endemic strain, VGII (subtypes IIa and IIc) was present in 10 of 11 patients; the median fluconazole minimum inhibitory concentration (MIC) was 12 μg/mL (range 2–32 μg/mL) for this strain. We found C. gattii infection among organ transplant recipients was disseminated at diagnosis, had low cerebrospinal fluid cryptococcal antigen titers, and was associated with an elevated fluconazole MIC and high attributable mortality.

Travel-associated Antimicrobial Drug–Resistant Nontyphoidal Salmonellae, 2004–2009

To evaluate trends in and risk factors for acquisition of antimicrobial-drug resistant nontyphoidal Salmonella infections, we searched Oregon surveillance data for 2004–2009 for all culture-confirmed cases of salmonellosis. We defined clinically important resistance (CIR) as decreased susceptibility to ampicillin, ceftriaxone, ciprofloxacin, gentamicin, or trimethoprim/sulfamethoxazole. Of 2,153 cases, 2,127 (99%) nontyphoidal Salmonella isolates were obtained from a specific source (e.g., feces, urine, blood, or other normally sterile tissue) and had been tested for drug susceptibility. Among these, 347 (16%) isolates had CIR. The odds of acquiring CIR infection significantly increased each year. Hospitalization was more likely for patients with than without CIR infections. Among patients with isolates that had been tested, we analyzed data from 1,813 (84%) who were interviewed. Travel to eastern or Southeast Asia was associated with increased CIR. Isolates associated with outbreaks were less likely to have CIR. Future surveillance activities should evaluate resistance with respect to international travel.

Impact of the US Maternal Tetanus, Diphtheria, and Acellular Pertussis Vaccination Program on Preventing Pertussis in Infants <2 Months of Age: A Case-Control Evaluation

BackgroundnInfants aged <1 year are at highest risk for pertussis-related morbidity and mortality. In 2012, Tdap (tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis) vaccine was recommended for women during each pregnancy to protect infants in the first months of life; data on effectiveness of this strategy are currently limited.nnnMethodsnWe conducted a case-control evaluation among pertussis cases <2 months old with cough onset between 1 January 2011 and 31 December 2014 from 6 US Emerging Infection Program Network states. Controls were hospital-matched and selected by birth certificate. Mothers were interviewed to collect information on demographics, household characteristics, and healthcare providers. Provider-verified immunization history was obtained on mothers and infants. Mothers were considered vaccinated during pregnancy if Tdap was received ≥14 days before delivery; trimester was calculated using Tdap date, infants date of birth, and gestational age. Odds ratios were calculated using multivariable conditional logistic regression; vaccine effectiveness (VE) was estimated as (1 - odds ratio) × 100%.nnnResultsnA total of 240 cases and 535 controls were included; 17 (7.1%) case mothers and 90 (16.8%) control mothers received Tdap during the third trimester of pregnancy. The multivariable VE estimate for Tdap administered during the third trimester of pregnancy was 77.7% (95% confidence interval [CI], 48.3%-90.4%); VE increased to 90.5% (95% CI, 65.2%-97.4%) against hospitalized cases.nnnConclusionsnVaccination during pregnancy is an effective way to protect infants during the early months of life. With a continuing resurgence in pertussis, efforts should focus on maximizing Tdap uptake among pregnant women.

Notes from the Field: Subacute Sclerosing Panencephalitis Death - Oregon, 2015.

In 2015, the Oregon Health Authority was notified of the death of a boy with subacute sclerosing panencephalitis (SSPE), a rare and fatal complication of measles. The patient, aged 14 years, had reportedly been vaccinated against measles in the Philippines at age 8 months. However, the patient contracted measles at age 1 year while still in the Philippines. He had been well until 2012, when his neurodegenerative symptoms began. After the diagnosis of SSPE was made, the patient remained in home hospice care until his death. Investigators from the Oregon Health Authority and the Oregon Health and Science University reviewed the patients medical records and interviewed the parents. Vaccination against measles can prevent not only acute measles and its complications, but also SSPE.

Physician Attitudes Regarding School-Located Vaccination Clinics

BACKGROUNDnSchool-located vaccination clinics offer an opportunity to target children for vaccination programs during communicable disease outbreaks. However, children in the United States are primarily vaccinated in the pediatricians or family physicians office, and the concept of school-located vaccinations may be unfamiliar to some parents and guardians. Physician support could contribute to effective implementation of school-located vaccination clinics during outbreak situations. The primary objective of the study was to assess physician opinion of using school-located vaccination clinics to administer both outbreak-specific and routine vaccines.nnnMETHODSnA statewide mail and Internet survey was administered to 275 pediatricians and 275 family physicians in Oregon during July and August 2010.nnnRESULTSnNinety-one percent of physicians supported the use of school-located vaccination clinics as immunization delivery sites during outbreak situations. Sixty percent of physicians supported using school-located vaccination clinics to administer routine vaccinations. Only 57% of physicians had knowledge of school-located vaccination clinic availability to their patients.nnnCONCLUSIONSnPediatricians and family physicians expressed strong support of school vaccination clinics as sites for immunization delivery during outbreak situations but significantly less support for administering routine vaccinations. Increasing physician awareness of school-located vaccination clinic availability and establishing partnerships between physician practices and school vaccination clinics may improve access to immunizations for school-aged children and adolescents, particularly during large-scale communicable disease outbreaks.

Duration of Shedding and Secondary Household Transmission of Shiga Toxin–Producing Escherichia coli O26 During an Outbreak in a Childcare Center, Oregon, October–December 2010

We assessed shedding duration and secondary household transmission of Shiga toxin 1-positive Escherichia coli O26 during a childcare-associated outbreak. No severe illness was noted. Shedding duration was 15-46 days (median, 29). No secondary transmission to household members was identified. Value of isolating asymptomatic infected children with this low-virulence infection remains uncertain.