Incidence of Herpes Zoster Among Children: 2003-2014.

BACKGROUND AND OBJECTIVES: After the 1996 introduction of routine varicella vaccination in the United States, most studies evaluating pediatric herpes zoster (HZ) incidence reported lower incidence over time, with varying degrees of decline. Using the combined databases of 6 integrated health care organizations, we examined HZ incidence in children over a 12-year period in the varicella vaccine era. METHODS: This study included children aged 0 through 17 years from 2003 through 2014. Using electronic medical records, we identified HZ cases through International Classification of Diseases, Ninth Revision diagnosis code 053. We calculated HZ incidence rates per 100 000 person years of health plan membership for all children and among children who were vaccinated versus unvaccinated. We calculated rates for the 12-year period and examined temporal trends. Among children who were vaccinated, we compared HZ rates by month and year of age at vaccination. RESULTS: The study included 6 372 067 children with ≥1 month of health plan membership. For the 12-year period, the crude HZ incidence rate for all subjects was 74 per 100 000 person years, and the rate among children who were vaccinated was 38 per 100 000 person years, which was 78% lower than that among children who were unvaccinated (170 per 100 000 person years; P < .0001). Overall HZ incidence declined by 72% (P < .0001) from 2003 through 2014. Annual rates in children who were vaccinated were consistently lower than in children who were unvaccinated. CONCLUSIONS: With this population-based study, we confirm the decline in pediatric HZ incidence and the significantly lower incidence among children who are vaccinated, reinforcing the benefit of routine varicella vaccination to prevent pediatric HZ.

Estimated rates of influenza-associated outpatient visits during 2001-2010 in 6 US integrated healthcare delivery organizations.

BACKGROUND: Population-based estimates of influenza-associated outpatient visits including both pandemic and interpandemic seasons are uncommon. Comparisons of such estimates with laboratory-confirmed rates of outpatient influenza are rare. OBJECTIVE: To estimate influenza-associated outpatient visits in 6 US integrated healthcare delivery organizations enrolling ~7.7 million persons. METHODS: Using negative binomial regression methods, we modeled rates of influenza-associated visits with ICD-9-CM-coded pneumonia or acute respiratory outpatient visits during 2001-10. These estimated counts were added to visits coded specifically for influenza to derive estimated rates. We compared these rates with those observed in 2 contemporaneous studies recording RT-PCR-confirmed influenza outpatient visits. RESULTS: Outpatient rates estimated with pneumonia visits were 39 (95% confidence interval [CI], 30-70) and 203 (95% CI, 180-240) per 10 000 person-years, respectively, for interpandemic and pandemic seasons. Corresponding rates estimated with respiratory visits were 185 (95% CI, 161-255) and 542 (95% CI, 441-823) per 10 000 person-years. During the pandemic, children aged 2-17 years had the largest increase in rates (when estimated with pneumonia visits, from 64 [95% CI, 50-121] to 381 [95% CI, 366-481]). Rates estimated with pneumonia visits were consistent with rates of RT-PCR-confirmed influenza visits during 4 of 5 seasons in 1 comparison study. In another, rates estimated with pneumonia visits during the pandemic for children and adults were consistent in timing, peak, and magnitude. CONCLUSIONS: Estimated rates of influenza-associated outpatient visits were higher in children than adults during pre-pandemic and pandemic seasons. Rates estimated with pneumonia visits plus influenza-coded visits were similar to rates from studies using RT-PCR-confirmed influenza.

Invasive Pneumococcal Disease Among HIV-Infected and HIV-Uninfected Adults in a Large Integrated Healthcare System.

It is unclear whether HIV-infected individuals remain at higher risk of invasive pneumococcal disease (IPD) compared with HIV-uninfected individuals. We conducted a cohort study of HIV-infected and demographically matched HIV-uninfected adults within Kaiser Permanente Northern California during the period 1996-2011. We used Poisson models to obtain rate ratios (RRs) for incident IPD associated with HIV infection and other risk factors. Among 13,079 HIV-infected and 137,643 HIV-uninfected adults, the IPD rate per 100,000 person-years was 160 (n = 109 events) for HIV-infected and 8 (n = 75 events) for HIV-uninfected subjects, with an adjusted RR of 13.0 [95% confidence interval (CI): 9.1-18.7]. For HIV-infected individuals, IPD incidence per 100,000 person-years decreased by 71% during study follow-up, from 305 in 1996-1999 to 88 in 2010-2011 (p < 0.001), with an adjusted RR of 6.6 (95% CI: 2.7-16.1) compared with HIV-uninfected subjects in 2010-2011. Risk factors for IPD among HIV-infected individuals included black compared with white race/ethnicity, smoking, cancer, and higher HIV RNA levels. The 23-valent pneumococcal polysaccharide vaccination was not associated with a reduced risk of IPD in HIV-infected or HIV-uninfected individuals. Among HIV-infected IPD cases, the most common serotype was 19A (33%), and 59% of serotypes were covered by the 13-valent pneumococcal conjugate vaccine (PCV13). Despite a dramatic decline in IPD incidence for HIV-infected adults since 1996, IPD rates were nearly sevenfold higher compared with HIV-uninfected adults in recent years, even after adjustment for risk factors. Timely antiretroviral therapy initiation, risk reduction strategies, and recent guidelines recommending PCV13 use may further reduce IPD incidence among HIV patients.

Case-centered Analysis of Optic Neuritis After Vaccines.

We evaluated the risk of optic neuritis (ON) after vaccines, using a case-centered analysis, comparing the time since vaccination for the patients with ON with that for all similar vaccinees in a large integrated health plan population. We did not detect any association between ON and receipt of any type of vaccine.

Incidence, microbiology, and patient characteristics of skin and soft-tissue infections in a U.S. population: a retrospective population-based study.

BACKGROUND: Skin and soft tissue infections (SSTIs) are commonly occurring infections with wide-ranging clinical manifestations, from mild to life-threatening. There are few population-based studies of SSTIs in the period after the rapid increase in community-acquired methicillin-resistant Staphyloccus aureus (MRSA). METHODS: We used electronic databases to describe the incidence, microbiology, and patient characteristics of clinically-diagnosed skin and soft tissue infections (SSTIs) among members of a Northern California integrated health plan. We identified demographic risk factors associated with SSTIs and MRSA infection. RESULTS: During the three-year study period from 2009 to 2011, 376,262 individuals experienced 471,550 SSTI episodes, of which 23% were cultured. Among cultured episodes, 54% were pathogen-positive. Staphylococcus aureus (S. aureus) was isolated in 81% of pathogen-positive specimens, of which nearly half (46%) were MRSA. The rate of clinically-diagnosed SSTIs in this population was 496 per 10,000 person-years. After adjusting for age group, gender, race/ethnicity and diabetes, Asians and Hispanics were at reduced risk of SSTIs compared to whites, while diabetics were at substantially higher risk compared to non-diabetics. There were strong age group by race/ethnicity interactions, with African Americans aged 18 to <50 years being disproportionately at risk for SSTIs compared to persons in that age group belonging to other race/ethnicity groups. Compared to Whites, S. aureus isolates of African-Americans and Hispanics were more likely to be MRSA (Odds Ratio (OR): 1.79, Confidence Interval (CI): 1.67 to 1.92, and, OR: 1.24, CI: 1.18 to 1.31, respectively), while isolates from Asians were less likely to be MRSA (OR: 0.73, CI: 0.68 to 0.78). CONCLUSIONS: SSTIs represent a significant burden to the health care system. The majority of culture-positive SSTIs were caused by S. aureus, and almost half of the S. aureus SSTIs were methicillin-resistant. The reasons for African-Americans having a higher likelihood, and Asians a lower likelihood, for their S. aureus isolates to be methicillin-resistant, should be further investigated.

Cervical intraepithelial neoplasia grade 3 and adenocarcinoma in situ: comparison of ICD-9 codes and pathology results--Kaiser Permanente, United States, 2000-2005.

BACKGROUND: Cervical intraepithelial neoplasia grade 3+ (CIN3+) and adenocarcinoma in situ incidence will be an important measure of HPV vaccine impact. Integrated healthcare delivery systems, such as Kaiser Permanente, could be used to monitor CIN3+ trends; however, limited evaluations of data from healthcare delivery systems for CIN3+ surveillance exist. METHODS: We compared CIN3+ diagnoses by ICD-9 code with CIN3+ diagnoses by pathology results among 121,211 females aged 11 to 30 years who were continuously enrolled from 2000 to 2005 in either Kaiser Permanente Northern California or Kaiser Permanente Northwest. We calculated sensitivity and positive predictive value of diagnosis by ICD-9 codes using pathology CIN3+ diagnosis as the gold standard. RESULTS: There were 1,090 women with at least one CIN3+ diagnosis by ICD-9 code 233.1 and 1,200 women with at least one CIN3+ diagnosis by pathology results. The sensitivity of the ICD-9 code for detecting a woman with at least one pathology diagnosis for CIN3+ was 62% (740/1,200); positive predictive value was 68% (740/1,090). Among women with at least one CIN3+ diagnosis by ICD-9 code, 679 (62%) had more than one visit with this code; whereas, among women with at least one CIN3+ diagnosis by pathology, 466 (39%) had more than one CIN3+ pathology result. CONCLUSIONS: ICD-9 codes may underestimate the number of women with at least one CIN3+ diagnosis. IMPACT: Pathology results, when available, may provide better estimates of CIN3+ incidence.

Prevalence of HPV types in cervical specimens from an integrated healthcare delivery system: baseline assessment to measure HPV vaccine impact.

PURPOSE: Two human papillomavirus (HPV) vaccines are available to prevent cervical cancer. One early measure of HPV vaccine impact would be a reduction in vaccine-related HPV types (HPV 6, 11, 16, or 18, or HPV 16, 18) in cervical samples from young women. We aimed to assess feasibility of specimen collection and baseline HPV prevalence in an integrated healthcare delivery system. METHODS: Residual cervical specimens collected during routine cervical cancer screening (2006-2008) were retained consecutively from eligible females aged 11-29 years, stratified by age group. Specimens were evaluated for 37 HPV genotypes using the Roche Linear Array assay. RESULTS: Of 10,124 specimens submitted, 10,103 (99 %) were adequate for HPV testing. Prevalence of HPV 6, 11, 16, or 18 genotype was 11.4 % overall and was the highest in the youngest age group (18.1 % in the 11-19-year-olds, 12.5 % in the 20-24-year-olds, and 7.0 % in the 25-29-year-olds). CONCLUSIONS: HPV types 6, 11, 16, or 18 prevalence could be measured over time to assess early HPV vaccine impact using residual specimens from an integrated healthcare delivery system, particularly if sampling focused on young women.

Epidemiologic and clinical features of Bell's palsy among children in Northern California.

BACKGROUND: Bell's palsy (BP) is an acute, idiopathic, and usually unilateral paralysis of the facial nerve. Large population-based studies of BP among children are lacking. We determined epidemiologic and clinical features of BP among children enrolled in a large integrated health care delivery system. METHODS: From 2001 through 2006, all children ≤18 years of age diagnosed with BP within the population of Kaiser Permanente Northern California were identified using the International Classification of Diseases, 9th Revision, code 351.0. All cases were adjudicated by an otolaryngologist and categorized as definite, probable, or rejected. Using chart abstraction forms, epidemiologic and clinical features of BP were determined. RESULTS: Of a total of 977 cases initially identified, 822 (84.1%) were adjudicated as a definite or probable case. The overall incidence rate of BP during the study period was 18.8 (95% CI 17.6-20.2) per 100,000 person-years. The incidence rate increased by age and was higher in females than males across all age strata. There was no evidence for a seasonal pattern in the occurrence of BP (p for trend = 0.81). CONCLUSIONS: BP among children may be more common than previously recognized.

Trends and characteristics of culture-confirmed Staphylococcus aureus infections in a large U.S. integrated health care organization.

Infections due to Staphylococcus aureus present a significant health problem in the United States. Between 1990 and 2005, there was a dramatic increase in community-associated methicillin-resistant S. aureus (MRSA), but recent reports suggest that MRSA may be declining. We retrospectively identified S. aureus isolates (n = 133,450) that were obtained from patients in a large integrated health plan between 1 January 1998 and 31 December 2009. Trends over time in MRSA were analyzed, and demographic risk factors for MRSA versus methicillin-susceptible S. aureus (MSSA) were identified. The percentage of S. aureus isolates that were MRSA increased from 9% to 20% between 1998 and 2001 and from 25% to 49% between 2002 and 2005 and decreased from 49% to 43% between 2006 and 2009. The increase in MRSA was seen in blood and in other bacteriological specimens and occurred in all age and race/ethnicity groups, though it was most pronounced in persons aged 18 to <50 years and African-Americans. Hospital onset infections were the most likely to be MRSA (odds ratio [OR], 1.58; confidence interval [CI], 1.46 to 1.70, compared to community-associated cases), but the largest increase in MRSA was in community-associated infections. Isolates from African-Americans (OR, 1.73; CI, 1.64 to 1.82) and Hispanics (OR, 1.11; CI, 1.06 to 1.16) were more likely to be MRSA than those from whites. After substantial increases between 1998 and 2005 in the proportion of S. aureus isolates that were MRSA, the proportion decreased between 2006 and 2009. Hospital onset S. aureus infections are disproportionately MRSA, as are those among African-Americans.

Case-control study of antibiotic use and subsequent Clostridium difficile-associated diarrhea in hospitalized patients.

OBJECTIVE: To determine which antibiotics increase or decrease the risk of Clostridium difficile-associated diarrhea (CDAD). DESIGN: Retrospective case-control study. SETTING: Nonprofit, integrated healthcare delivery system in Northern California. PATIENTS: Study participants included patients with cases of hospital-acquired CDAD that occurred during the period from 1999 through 2005 (n=1,142) and control patients (n= 3,351) matched for facility, calendar quarter during which hospitalization occurred, diagnosis related group for the index hospitalization, and length of hospital stay. All case and control patients had received antibiotics in the 60 days before the index date. For each antibiotic, the risk of CDAD was examined in relation to whether the patient received the antibiotic, after adjustment for use of other antibiotics, demographic characteristics, selected health conditions, and use of healthcare services. RESULTS: The following antibiotics were associated with a significantly increased risk of acquiring CDAD: imipenem-cilastin (odds ratio [OR], 2.77), clindamycin (OR, 2.31), cefuroxime (OR, 2.16), moxifloxacin (OR, 1.88), ceftazidime (OR, 1.82), cefpodoxime (OR, 1.58), ceftizoxime (OR, 1.57), and ceftriaxone (OR, 1.49). Metronidazole and doxycycline were associated with a significantly reduced risk of CDAD (OR for metronidazole, 0.67; OR for doxycycline, 0.41). Other factors associated with an increased risk of CDAD were older age, longer hospital stays, use of proton pump inhibitors, prior gastrointestinal disease, and prior infection (not including C. difficile infection.) CONCLUSIONS: Some antibiotics appear to increase the risk of acquiring CDAD, notably clindamycin, third-generation cephalosporins, and carbapenems, whereas metronidazole and doxycycline appear to be protective, compared with other antibiotics.

Hospital-level rates of fluoroquinolone use and the risk of hospital-acquired infection with ciprofloxacin-nonsusceptible Pseudomonas aeruginosa.

BACKGROUND: In recent years, Pseudomonas aeruginosa has become increasingly resistant to fluoroquinolones, and fluoroquinolone use in the United States has also increased. Our objective was to determine whether higher hospital-level rates of use of ciprofloxacin, levofloxacin, and moxifloxacin antimicrobials were predictors that a higher proportion of P. aeruginosa isolates from hospital-acquired infections (hereafter, "hospital-acquired isolates") would be nonsusceptible to ciprofloxacin. METHODS: We identified all hospital-acquired isolates from 14 hospitals in the Northern California Kaiser Permanente health care delivery system between 1998 and 2003 and determined their susceptibility to ciprofloxacin. For each facility, we determined the number of days of fluoroquinolone use per 1000 patient-days, by calendar quarter. We used a logistic regression model to analyze the data, with susceptibility status as the outcome variable. Hospital-level rates of use of the 3 fluoroquinolones were the predictors of interest; we adjusted for year, for use of nonquinolone antimicrobials, and for patient variables, including the number of days spent in the hospital in the prior year and fluoroquinolone use in the prior year. The model tested whether isolates from those facilities with higher rates of use of antimicrobials were more likely to be nonsusceptible to ciprofloxacin. RESULTS: Of 6099 isolates tested, 15% were not susceptible to ciprofloxacin. The nonsusceptibility rate increased from 9% to 20% between 1998 and 2003. Both the overall rate of use at the hospital and prior patient-specific use of ciprofloxacin, levofloxacin, and moxifloxacin were found to be independent predictors that a subsequent P. aeruginosa isolate would be nonsusceptible to ciprofloxacin. CONCLUSIONS: Higher hospital-level rates of use of ciprofloxacin, levofloxacin, and moxifloxacin are each associated with an increased proportion of hospital-acquired P. aeruginosa isolates being nonsusceptible to ciprofloxacin.

Postlicensure surveillance for pneumococcal invasive disease after use of heptavalent pneumococcal conjugate vaccine in Northern California Kaiser Permanente.

OBJECTIVE: To assess the direct and indirect effects of the introduction of routine use of pneumococcal conjugate vaccine in infants and toddlers at risk for invasive disease caused by vaccine serotypes and nonvaccine serotypes in vaccinated children and unvaccinated children of the same age. Secondary objectives included determination of the risk of pneumococcal infections in unvaccinated older children and adults in the same population and the impact of vaccine introduction on patterns of antimicrobial resistance. METHODS: Northern California Kaiser Permanente provides integrated comprehensive care to 3.1 million people and has an annual birth cohort of 38,000 infants. Microbiology services use a regional laboratory. Automated laboratory results, immunization records as well as diagnoses for inpatient and outpatient utilization are available from clinical data bases. Beginning in April 2000, the heptavalent pneumococcal conjugate (PNCV7) vaccine was introduced into routine use in the Northern California Kaiser Permanente population. Cases of invasive pneumococcal disease were identified from the automated hospital diagnosis as well as laboratory databases for all individuals, vaccinees and nonvaccinees, inpatient and outpatient. For the purpose of these analyses, pneumococcal invasive disease was defined as a positive culture from a normally sterile site. RESULTS: As of March 2003, 157,471 children had received 1 dose or more of PNCV7, but only 24% of those <2 years of age received all 4 doses as a result of shortages of vaccine. During the last year of observation, no cases of vaccine serotype disease were seen in children <1 year of age compared with an incidence ranging between 51.5 and 98.2 cases per 100,000 person-years (16-34 cases per year) in the years before vaccine introduction. Similar reductions were seen in children <5 years of age. There was no evidence of any concomitant increase in pneumococcal disease caused by nonvaccine serotypes. High level resistance of pneumococci to penicillin fell from a peak of 15% in 2000 to 5% in the first half of 2003. Similar trends were seen for other antibiotics. CONCLUSION: The PNCV7 vaccine is highly effective in reducing the burden of pneumococcal disease in children <5 years of age, and there is evidence of a herd effect as well as a decrease in the antibiotic resistant in strains causing disease. For invasive disease, there is no current evidence of serotype replacement.