The association between pneumococcal vaccination, ethnicity, and the nasopharyngeal microbiota of children in Fiji.

BACKGROUND: Streptococcus pneumoniae is a significant global pathogen that colonises the nasopharynx of healthy children. Pneumococcal conjugate vaccines, which reduce nasopharyngeal colonisation of vaccine-type S. pneumoniae, may have broader effects on the nasopharyngeal microbiota; however, data are limited. In Fiji, nasopharyngeal carriage prevalence of S. pneumoniae and other colonising species differ between the two main ethnic groups. Here, we examined the association between the 7-valent pneumococcal conjugate vaccine (PCV7) and the nasopharyngeal microbiota of children in Fiji, including for each of the two main ethnic groups-indigenous Fijians (iTaukei) and Fijians of Indian descent (FID). METHOD: The nasopharyngeal microbiota of 132 Fijian children was examined using nasopharyngeal swabs collected from 12-month-old iTaukei and FID children who were vaccinated (3 doses PCV7) or unvaccinated in infancy as part of a phase II randomised controlled trial. Microbiota composition was determined by sequencing the V4 region of the 16S rRNA gene. Species-specific carriage of S. pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Staphylococcus aureus was determined using real-time quantitative PCR. Associations between microbiota composition and other host and environmental factors were considered in the analysis. RESULTS: PCV7 had no overall impact on microbial diversity or composition. However, ethnic differences were observed in both diversity and composition with iTaukei children having higher relative abundance of Moraxella (p = 0.004) and Haemophilus (p = 0.004) and lower relative abundance of Staphylococcus (p = 0.026), Dolosigranulum (p = 0.004) and Corynebacterium (p = 0.003) compared with FID children. Further, when we stratified by ethnicity, associations with PCV7 could be detected: vaccinated iTaukei children had a lower relative abundance of Streptococcus and Haemophilus compared with unvaccinated iTaukei children (p = 0.022 and p = 0.043, respectively); and vaccinated FID children had a higher relative abundance of Dolosigranulum compared with unvaccinated FID children (p = 0.037). Children with symptoms of an upper respiratory tract infection (URTI) had a significantly different microbiota composition to children without symptoms. The microbiota composition of iTaukei children without URTI symptoms was most similar to the microbiota composition of FID children with URTI symptoms. CONCLUSIONS: Associations between PCV7 and nasopharyngeal microbiota differed within each ethnic group. This study highlights the influence that ethnicity and URTIs have on nasopharyngeal microbiota.

Invasive pneumococcal disease and serotype emergence in the Auckland region during the vaccine era 2009-16.

INTRODUCTION There is a deficit of knowledge in New Zealand as the epidemiology of invasive pneumococcal disease varies significantly between countries. AIM Time trends and sociodemographic characteristics of cases of invasive pneumococcal disease (IPD) in the Auckland region are reviewed after the introduction of a conjugate vaccination, to provide evidence for future vaccine policy and to ensure Auckland region analysis is representative of national trends for subsequent IPD analysis. METHODS Data on all cases of IPD occurring in Waitemata, Auckland and Counties Manukau District Health Boards between 2009 and 2016 were extracted from EpiSurv. Denominator data were drawn from mid-year estimates supplied by Statistics New Zealand. Descriptive epidemiology and time-series regression was performed to analyse trends. RESULTS Rates of IPD have fallen in the Auckland region over the past 8 years by 32%. While absolute rates in the elderly have reduced by 12%, they have the highest disease burden at 32/100,000. The ethnic disparity continues with Pacific people (33/100,000) and Maori (14/100,000) over represented compared to European (10/100,000). In the elderly, the 19A serotype has increased from an incidence of 0 in 2008 to 8.2/100,000. DISCUSSION Large ethnic and age-related disparities are observed in the Auckland region, consistent with the rest of the country, since the start of the pneumococcal vaccination era. Extending immunisation to the elderly may help close these gaps. As with other countries, there is 19A serotype replacement occurring following conjugate vaccine introduction.

Epidemiology of invasive pneumococcal disease in indigenous and non-indigenous adults in northwestern Ontario, Canada, 2006-2015.

BACKGROUND: Despite the use of pneumococcal vaccines, indigenous populations are consistently disproportionately affected by invasive pneumococcal disease (IPD). With recent changes in Ontario's provincial pneumococcal vaccination program, we sought to evaluate the epidemiology and burden of IPD in northwestern Ontario (NWO) Canada - a region that contains a substantial (19.2%) indigenous population. METHODS: We retrospectively reviewed all adult cases of IPD that were reported to the Thunder Bay District Health Unit, in Thunder Bay, Ontario, Canada, over a 10-year period (2006-2015). Patients admitted to the Thunder Bay Regional Health Sciences Centre with IPD had their charts reviewed to abstract clinical data. Statistical analysis, including incidence rates of IPD, was performed. RESULTS: Two hundred sixty-two cases of IPD occurred over the 10-year observation period and clinical data was available for 182 cases. Fifty-three of 182 (29.1%) patients were indigenous. 73 of 182 (40.1%) of patients were immunocompromised. Indigenous patients with IPD were more likely to be immunocompromised than non-indigenous patients (p < 0.001). Serotype data was available for 159 cases of IPD; PCV7, PCV13, and PPV23 covered 5.7%, 28.3%, and 79.2% of isolates, respectively, while 29 (20.8%) were non-vaccine serotypes. The annual incidence rate of IPD ranged from 8.9 to 25.9 per 100,000 among adults 18-64 years old; among adults 65 years of age and older the annual incidence of IPD ranged from 18.5 to 60.7 per 100,000. CONCLUSION: Among adults in NWO, Canada, there is a high incidence of IPD. Immunocompromised indigenous adults in NWO may benefit from pneumococcal vaccination coverage. Emerging non-vaccine serotypes of Streptococcus pneumoniae warrant the consideration of the provincial pneumococcal vaccination program.

Racial/Ethnic Disparities in Influenza and Pneumococcal Vaccinations Among Nursing Home Residents: A Systematic Review.

This systematic review analyzes research examining racial/ethnic disparities in influenza and pneumococcal vaccination coverage between White and racial/ethnic minority (Black and Hispanic) nursing home residents. A review of the literature for years 1966-2014 using Medline, Web of Science, and PubMed was conducted. The Epidemiological Appraisal Instrument was used to appraise the quality of the 13 included studies. Overall, articles were strong in reporting and data analysis, but weak in sample selection and measurement quality. Disparities between vaccination coverage among racial/ethnic minorities versus Whites ranged from 2% to 20% for influenza and 6% to 15% for pneumococcal vaccination. Researchers reported racial/ethnic minorities were more likely to refuse vaccinations and less likely to have vaccinations offered and their vaccination status tracked compared to Whites. Policies/strategies that focus on ensuring racial/ethnic minorities are offered influenza and pneumococcal vaccinations and their vaccination status are tracked in nursing homes are warranted. Updated evaluation on vaccination disparities is also needed.

Repeat pneumococcal polysaccharide vaccine in Indigenous Australian adults is associated with decreased immune responsiveness.

BACKGROUND: Indigenous adults residing in the Northern Territory of Australia experience elevated rates of invasive pneumococcal disease despite the routine use of 23-valent pneumococcal polysaccharide vaccine (23vPPV). We hypothesised that the limited protection from 23vPPV may be due to hyporesponsiveness as a result of vaccine failure from repeated vaccination. To explore this possibility, we evaluated the immune response to a first and second dose of 23vPPV in Indigenous adults and a first dose of 23vPPV in non-Indigenous adults. METHODS: Serotype-specific IgG was measured by ELISA for all 23 vaccine serotypes at baseline and at one month post-vaccination. Individuals were considered to have an adequate immune response if paired sera demonstrated either: a four-fold rise in antibody concentration; a two-fold rise if the post vaccination antibody was >1.3µg/ml but <4.0µg/ml; or a post-vaccination antibody concentration >4.0µg/ml for at least half of the serotypes tested (12/23). Our per-protocol analysis included the comparison of outcomes for three groups: Indigenous adults receiving a second 23vPPV dose (N=20) and Indigenous (N=60) and non-Indigenous adults (N=25) receiving their first 23vPPV dose. RESULTS: All non-Indigenous adults receiving a first dose of 23vPPV mounted an adequate immune response (25/25). There was no significant difference in the proportion of individuals with an adequate response using our definition (primary endpoint), with 88% of Indigenous adults mounted an adequate response following first dose 23vPPV (53/60) compared to 70% having an adequate response following a second dose of 23vPPV (14/20; p=0.05). The risk difference between Indigenous participants receiving first dose compared to non-Indigenous participants receiving first dose was significant when comparing a response threshold of at least 70% (-27%, 95% CI: -43% to -11%; p=0.01) and 90% (-38%, 95% CI: -60% to -16%; p=0.006) of serotypes with a positive response. CONCLUSION: Indigenous participants demonstrated a poorer response to a first dose 23vPPV compared to their non-Indigenous counterparts, with lower IgG following a second 23vPPV dose. These findings highlight the critical need to evaluate the efficacy of future pneumococcal vaccine programs in the Australian Indigenous populations that recommend repeated doses of 23vPPV.

Understanding Black Patients' Refusal of Pneumococcal Vaccination.

OBJECTIVE: Racial disparities in rates of pneumococcal vaccine (PPSV23) exist. In one practice, 3.1 % of white patients refused PPSV23 following doctor recommendation, whereas 11.2 % of black patients refused vaccination. Our objective was to understand reasons black patients refused PPSV23. METHODS: Mixed-method telephone survey in 2012 of black patients aged ≥65 with a documented refusal of PPSV23. The survey assessed beliefs about PPSV23; reasons for non-receipt of PPSV23; receipt of other vaccinations; and comparative perceptions of adult vs. childhood vaccines. Participants responded to items on a Likert scale ranging from 1 (strongly disagree) to 5 (strongly agree). RESULTS: Participants' (N = 40) mean age was 73 years; 95 % were female. Participants recognized pneumonia could be deadly (M = 4.3, SD = 1.0), but reported low levels of personal susceptibility (M = 2.8, SD = 1.4). Participants perceived childhood vaccines to be safer (M = 4.2, SD = 1.2) than adult vaccines (M = 3.4, SD = 1.4; p < 0.01). Qualitative analyses to understand reasons for refusal of vaccine both reinforced identified low perceptions of personal susceptibility as well as identified numerous additional barriers to receipt of PPSV23 (e.g., fear, side effects, and mistrust). CONCLUSIONS: Black patients in our sample who refused PPSV23 may not perceive themselves susceptible to the disease, suggesting that strategies to improve PPSV23 rates among these patients may need to emphasize susceptibility to pneumonia. Further, given the discrepancies in perceptions toward childhood versus adult vaccinations, focusing on vaccination across the lifespan may be a promising vaccine promotion strategy.

Using Pneumococcal Carriage Data to Monitor Postvaccination Changes in the Incidence of Pneumococcal Otitis Media.

Pneumococcal conjugate vaccines (PCVs) have substantially reduced the burden of pneumococcal disease, including the incidence of otitis media (OM). However, in most countries, no surveillance exists to monitor the change in pneumococcal OM incidence after the introduction of PCVs. We explored whether measuring pneumococcal carriage was a useful surrogate for monitoring postvaccination changes in the incidence of pneumococcal OM. The 7-valent PCV was introduced to Israel's national immunization program in July 2009 and gradually replaced by the 13-valent PCV starting in November 2010. Each day since 2009, nasopharyngeal swabs have been obtained from the first 4 Bedouin children and the first 4 Jewish children who were younger than 5 years old and attended a pediatric emergency room in southern Israel. During the same time, OM surveillance in southern Israel included all children younger than 2 years of age who were diagnosed with OM and had undergone a middle-ear fluid culture. The relative change in the prevalence of vaccine-serotype (VT) pneumococcal carriage was predictive of the relative change in incidence of OM due to VT pneumococcus. However, the serotype replacement observed in non-VT carriage is not paralleled in the incidence of OM due to non-VT pneumococcus. This could indicate that there are more complex mechanisms of the immune response involved in preventing initial and consecutive episodes of OM, which has been changed through declining prevalence of the most virulent serotypes as a result of vaccination.

Disparities in PCV impact between different ethnic populations cohabiting in the same region: A systematic review of the literature.

BACKGROUND: Invasive pneumococcal disease (IPD) and pneumonia are major causes of morbidity, especially in developing countries. While pneumococcal disease rates differences between various populations are well known, data are scarce regarding disparities in PCV impact on pneumococcal disease rates between populations living in the same country. OBJECTIVE: The aim of this systematic literature review was to describe disparities in PCV impact between different populations. METHODS: A systematic literature search was performed using the PubMed database. Studies evaluating pneumococcal disease rates at any age were included. The search was limited to articles written in English and published between 2000 and 2015. Independent extraction of articles was performed by two authors (NS, SB-S). Search terms included: pneumococcus, pneumococcal disease, IPD, pneumonia, PCV, pneumococcal vaccine, population, race, ethnicity, differences, and disparity. We defined resource-poor populations as African-Americans, Aboriginal, Alaska natives and Navajo native-Americans populations compared with the respective resource-rich populations, including White, non-Aboriginal, non-Alaska natives and general US population. RESULTS: Eighteen articles meeting the selection criteria were identified; 17 regarding IPD and one regarding pneumonia. Nine articles compared IPD rates in African-Americans and Whites in the US, six compared Aboriginal and non-Aboriginal populations; two compared Alaska natives vs. non-native Alaskans in the US and one article compared Navajo native-Americans and general population in the US. Only minor difference where usually noted in the incidence rate ratios (IRRs) comparing pre- and post-PCV rates of IPD and pneumonia between resource rich and resource poor populations. In contrast, absolute rate reductions were higher in resource-poor compared with resource-rich populations. CONCLUSION: While differences in IPD and pneumonia rates between resource-poor and resource-rich populations were decreased following PCV introduction, disparity is still apparent and is not fully eliminated in any of the studies. Younger (<2years) populations in resource-poor populations seem to benefit the most from PCV introduction.

Modeling pneumococcal nasopharyngeal acquisition as a function of anticapsular serum antibody concentrations after pneumococcal conjugate vaccine administration.

BACKGROUND: A prior 7- and 13-valent pneumococcal conjugate vaccine (PCV7 and PCV13) study provided sufficient data (N=1754; Jewish, n=1154; Bedouin, n=595; other, n=5) to investigate the association between nasopharyngeal (NP) acquisition of common PCV7 serotypes and cross-reacting 6A (PCV7+6A) and IgG concentrations. METHODS: Using a logistic regression model, serotype specific association between postinfant series IgG concentration (age 7months) and new NP acquisition between ages 7 and 24months was assessed and adjusted for ethnicity. From a subset of subjects with new NP acquisition (n=9-152 across serotypes studied), new acquisition percentiles and associated IgG concentrations were calculated. RESULTS: For the serotypes studied, new NP acquisition rates decreased as IgG concentrations increased. Ethnicity did not influence these associations despite differences in carriage rates. From the subset with new acquisitions, 50% of the events occurred at IgG concentrations >0.61-5.58µg/mL; and 10% of the acquisitions occurred at IgG concentrations >2.48-17.69µg/mL. CONCLUSION: Remarkably high IgG concentrations are required to reduce NP acquisition. These IgG concentrations differ between serotypes. Ethnicity did not influence the association between high IgG concentrations and prevention of carriage despite differences in carriage rates. Since carriage determines transmission, these results may have important implications for herd protection. TRIAL REGISTRATION: ClinicalTrials.gov number, NCT00508742; http://clinicaltrials.gov/ct2/show/NCT00508742.

Addressing Pneumococcal Vaccine Uptake Disparities among African-American Adults in the United States.

OBJECTIVE: Pneumococcal illnesses affect over one million Americans annually, making invasive pneumococcal disease (pneumonia) the most prevalent vaccine-preventable illness. Despite well-documented vaccine safety and efficacy, pneumococcal vaccine (PPSV23) uptake remains low, particularly among minorities. This study sought to define variables predicting PPSV23 uptake in eligible African-American (AA) adults. DESIGN AND SAMPLE: This was a cross-sectional study using a combined version of the Health Belief (HBM) and Precaution Adoption Process Models (PAPM). A convenience sample of 295 AA adults self-administered the Vaccine Uptake Questionnaire (VUQ). MEASURES: Bivariate chi-square analyses were conducted and significant variables evaluated using backward stepwise logistic regression. RESULTS: PPSV23 uptake was 32.2% (n = 95). Older age, female gender, vaccine awareness, increased knowledge, higher trust scores, perceived susceptibility, and presence of provider recommendation for PPSV23 predicted vaccine uptake. In regression modeling, age, awareness, and provider recommendation remained significant predictors with younger age, unawareness, and lack of provider recommendation decreasing the likelihood of vaccination. CONCLUSION: Three dimensions of the HBM (barriers, cues, and susceptibility) predicted PPSV23 uptake. With 147 (47.8%) unaware of PPSV23 existence prior to this study, adding the dimension "unaware" from the PAPM may strengthen the model and assist efforts to increase PPSV23 uptake among AA adults.

Racial and Regional Differences in Rates of Invasive Pneumococcal Disease.

BACKGROUND AND OBJECTIVES: Invasive pneumococcal disease (IPD) remains an important cause of illness in US children. We assessed the impact of introduction of the 13-valent pneumococcal conjugate vaccine (PCV13) on pediatric IPD rates, as well as changes in racial and regional differences in IPD, in Tennessee. METHODS: Data from active laboratory and population-based surveillance of IPD were used to compare IPD rates in the early-PCV7 (2001-2004), late-PCV7 (2005-2009), and post-PCV13 (2011-2012) eras. IPD rates were further stratified according to age, race, and region (east and middle-west TN). RESULTS: Among children aged <2 years, IPD rates declined by 70% from 67 to 19 per 100 000 person-years in the early-PCV7 era and post-PCV13 era, respectively. Similar decreasing trends in IPD rates were observed in older children aged 2 to 4 years and 5 to 17 years. In the late-PCV7 era, IPD rates in children aged <2 years were higher in black children compared with white children (70 vs 43 per 100 000 person-years); however, these racial differences in IPD rates were no longer significant after PCV13 introduction. Before PCV13, IPD rates in children aged <2 years were also higher in east Tennessee compared with middle-west Tennessee (91 vs 45 per 100 000 person-years), but these differences were no longer significant in the post-PCV13 era. CONCLUSIONS: PCV13 introduction led to substantial declines in childhood IPD rates and was associated with reduced regional and racial differences in IPD rates in Tennessee.

Nationwide population-based surveillance of invasive pneumococcal disease in Japanese children: Effects of the seven-valent pneumococcal conjugate vaccine.

BACKGROUND: In Japan, the seven-valent pneumococcal conjugate vaccine (PCV7) was introduced in 2010. PCV13 has replaced PCV7 since November 2013. METHODS: The effectiveness of PCV7 in protecting against invasive pneumococcal disease (IPD) in children aged <5 years was evaluated in a nationwide active population-based surveillance of IPD in 2008-2013 in 10 prefectures in Japan. RESULTS: 1181 cases were identified; 711 pneumococcal strains were analyzed for serotyping and antimicrobial resistance. Compared with the baseline IPD incidence (25.0 per 100,000), a 98% decline in IPD caused by PCV7 serotypes was found after the introduction of PCV7. This was partially offset by an increased incidence of IPD caused by PCV13 minus PCV7 and non-PCV13 serotypes, resulting in a 57% decline in overall IPD incidence. Absolute increases in the incidence rates of IPD caused by PCV13 minus PCV7 and non-PCV13 serotypes were 2.1 and 2.8 per 100,000 during the study period, respectively. The proportion of meropenem-nonsusceptible strains, especially with serotypes 19A and 15A, increased significantly after PCV7 introduction. CONCLUSIONS: Our data confirmed a 98% decline in IPD incidence caused by PCV7 serotypes in children aged <5 years and serotype replacement after PCV7 introduction. This shows the importance of continuing surveillance of serotypes responsible for IPD and their antimicrobial resistance in Japan.

Cost-effectiveness of programs to eliminate disparities in elderly vaccination rates in the United States.

BACKGROUND: There are disparities in influenza and pneumococcal vaccination rates among elderly minority groups and little guidance as to which intervention or combination of interventions to eliminate these disparities is likely to be most cost-effective. Here, we evaluate the cost-effectiveness of four hypothetical vaccination programs designed to eliminate disparities in elderly vaccination rates and differing in the number of interventions. METHODS: We developed a Markov model in which we assumed a healthcare system perspective, 10-year vaccination program and lifetime time horizon. The cohort was the combined African-American and Hispanic 65 year-old birth cohort in the United States in 2009. We evaluated five different vaccination strategies: no vaccination program and four vaccination programs that varied from "low intensity" to "very high intensity" based on the number of interventions deployed in each program, their cumulative cost and their cumulative impact on elderly minority influenza and pneumococcal vaccination rates. RESULTS: The very high intensity vaccination program ($24,479/quality-adjusted life year; QALY) was preferred at willingness-to-pay-thresholds of $50,000 and $100,000/QALY and prevented 37,178 influenza cases, 342 influenza deaths, 1,158 invasive pneumococcal disease (IPD) cases and 174 IPD deaths over the birth cohort's lifetime. In one-way sensitivity analyses, the very high intensity program only became cost-prohibitive (>$100,000/QALY) at less likely values for the influenza vaccination rates achieved in year 10 of the high intensity (>73.5%) or very high intensity (<76.8%) vaccination programs. CONCLUSIONS: A practice-based vaccination program designed to eliminate disparities in elderly minority vaccination rates and including four interventions would be cost-effective.

Racial disparities in invasive Streptococcus pneumoniae infections, 1998-2009.

BACKGROUND: Before the introduction of 7-valent pneumococcal conjugate vaccine (PCV7), invasive pneumococcal disease (IPD) rates among blacks were twice the rates in whites. We measured the effects of trends in PCV7-type and non-PCV7-type IPD rates on racial disparities in overall IPD and estimated the proportion of IPD caused by serotypes included in the 13-valent pneumococcal conjugate vaccine (PCV13). METHODS: We analyzed data from the Active Bacterial Core surveillance system, which performs active, laboratory- and population-based surveillance for IPD for 29.2 million people in the United States, for the period 1998-2009. For patients with unknown race, we multiplied imputed race to calculate age-, race-, and serotype-specific IPD incidence rates. RESULTS: During 1998-2009, 47 449 IPD cases were identified; race was unknown for 5419 (11%). After multiple imputation, 31 981 (67%) patients were considered white and 13 750 (29%) black. PCV7-type IPD rates in all ages in both races decreased to <1 case per 100 000, whereas there were no decreases in overall IPD rates after 2002. By 2009, PCV13 serotypes caused 71% of cases among whites aged <5 years compared with 58% among blacks (P < .01). PCV13 serotypes caused 50% of IPD cases in whites aged ≥5 years compared with 43% among blacks (P < .01). CONCLUSIONS: Despite near elimination of PCV7-type IPD in both races, overall disparities in IPD rates persisted because non-PCV7-type IPD rates are higher among blacks. Whereas PCV13 introduction may reduce racial disparities in IPD, higher valency conjugate vaccines and strategies to directly address underlying causes are needed to eliminate IPD disparities.

Socioeconomic and racial disparities of pediatric invasive pneumococcal disease after the introduction of the 7-valent pneumococcal conjugate vaccine.

BACKGROUND: Racial differences have been well described for invasive pneumococcal disease (IPD), but little information exists on how race interacts with community socioeconomic factors. METHODS: The Active Bacterial Core surveillance/Emerging Infections Program performed active surveillance for IPD in the 20-county Metropolitan Atlanta area. All IPD cases among children younger than 5 years from 2001 to 2009 were geocoded and linked to census tract-level socioeconomic measures from the 2000 US Census. Race- and socioeconomic-specific average annual incidence rates per 100,000 population were calculated. Trends in IPD incidence were determined by χ² tests for trend. Rate ratios (RRs) and 95% confidence intervals (CIs) were estimated using Poisson regression. RESULTS: IPD incidence among the total population of children increased as percentage of household poverty increased (P = 0.002), as median household income decreased (P < 0.001), as wealth decreased (P = 0.018) and as percentage of individuals with less than a high school education increased (P = 0.023). After stratifying by race, there was no significant linear trend between socioeconomic characteristics and IPD incidence among white children; among black children, however, IPD incidence decreased as socioeconomic conditions worsened. Despite adjusting for sex and socioeconomic factors, the IPD rate remained higher among black children compared with white children (RR = 1.60; 95% CI: 1.39-1.84). Differences in RR of IPD associated with highest poverty and lowest wealth noted in 2001 [RR = 2.71 (95% CI: 2.17-3.39) and 1.80 (95% CI: 1.09-2.96), respectively] declined in 2009 [RR = 1.33 (95% CI: 0.90-1.96) and 0.76 (95% CI: 0.48-1.19), respectively]. CONCLUSIONS: Although socioeconomic disparities in IPD incidence exist among children, the association between socioeconomic characteristics and IPD rates may differ by race and may change over time. Community-level socioeconomic factors did not account for racial differences in IPD incidence.

Streptococcus pneumoniae non-susceptibility and outpatient antimicrobial prescribing rates at the Alaska Native Medical Center.

BACKGROUND: American Indian/Alaska Native (AI/AN) people suffer substantially higher rates of invasive pneumococcal disease (IPD) than the general US population. We evaluated antimicrobial prescribing data and their association with non-susceptibility in Streptococcus pneumoniae causing IPD in AI/AN people between 1992 and 2009. METHODS: Antimicrobial use data were gathered from the electronic patient management system and included all prescriptions dispensed to Alaska Native patients aged 5 years and older from outpatient pharmacies at the Alaska Native Medical Center (ANMC). Antimicrobial susceptibility data were gathered from pneumococcal isolates causing IPD among Anchorage Service Unit AI/AN residents aged 5 years and older. Data were restricted to serotypes not contained in the pneumococcal vaccine (PCV7). RESULTS: Over the study period, overall antimicrobial prescribing increased 59% (285/1,000 persons/year in 1992 to 454/1,000 persons per year in 2009, p<0.001). Trimethoprim/sulfamethoxazole prescribing increased (43/1,000 persons/year in 1992 to 108/1,000 persons/year in 2009, p<0.001) and non-susceptibility to trimethoprim/sulfamethoxazole in AI/AN patients ≥5 years of age increased in non-PCV7 serotypes (0-12%, p<0.05). Similarly, prescribing rates increased for macrolide antibiotics (46/1,000 persons/year in 1992 to 84/1,000 persons/year in 2009, p<0.05). We observed no statistically significant change over time in erythromycin non-susceptibility among non-PCV7 serotypes in AI/AN patients aged 5 years or greater (0-7%, p=0.087). CONCLUSION: Antimicrobial prescribing patterns of some antibiotics in the AI/AN population corresponded to increased antimicrobial resistance in clinical isolates. This study highlights the on-going threat of antimicrobial resistance, the critical importance of judicious prescribing of antibiotics and the potential utility of prescribing data for addressing this issue.

The epidemiology of invasive pneumococcal disease in the Canadian North from 1999 to 2010.

INTRODUCTION: The International Circumpolar Surveillance network is a population-based surveillance system that collects data on invasive pneumococcal disease (IPD) in Northern Canada. A 7-valent pneumococcal conjugate vaccine was first introduced in some regions of Northern Canada in 2002, followed by 10-valent (2009) and 13-valent (PCV-13) vaccines (2010). A 23-valent polysaccharide (PPV-23) vaccine was first introduced in 1988 for special populations and adults aged 65 years and older. To describe the epidemiology in the context of pneumococcal vaccination programs, we analysed surveillance data from Northern Canada from 1999 to 2010. METHODS: A standardized case report form capturing demographic and clinical information was completed for all IPD cases in Northern Canada meeting the national case definition. Isolates were sent to a reference laboratory for confirmation, serotyping and antimicrobial resistance testing. Both laboratory and epidemiological data were sent to the Public Health Agency of Canada for analysis. Population denominators were obtained from Statistics Canada. RESULTS: From 1999 to 2010, 433 IPD cases were reported (average 36 cases per year). Incidence was greatest among infants aged < 2 years and among those aged 65 years and older, with an average annual incidence of 133 and 67 cases per 100,000 population, respectively. After a peak in incidence in 2008, rates among infants have declined. Incidence rates varied from 2 to 16 times greater, depending on the year, among Aboriginals compared to non-Aboriginals. Hospitalization was reported in 89% of all cases and the case fatality ratio was 6.0%. Clinical manifestations varied, with some patients reporting > 1 manifestation. Pneumonia was the most common (70%), followed by bacteremia/septicaemia (30%) and meningitis (8%). Approximately, 42% of cases aged < 2 years in 2009 and 2010 had serotypes covered by the PCV-13. In addition, the majority (89%) of serotypes isolated in cases aged 65 years and older were included in the PPV-23 vaccine. CONCLUSION: IPD continues to be a major cause of disease in Northern Canadian populations, with particularly high rates among infants and Aboriginals. Continued surveillance is needed to determine the impact of conjugate pneumococcal vaccine programs. Additional studies investigating factors that predispose infants and Aboriginal peoples would also be beneficial.