Group A Streptococcus Primary Peritonitis in Children, New Zealand.

Group A Streptococcus (GAS) primary peritonitis is a rare cause of pediatric acute abdomen (sudden onset of severe abdominal pain); only 26 pediatric cases have been reported in the English language literature since 1980. We discuss 20 additional cases of pediatric primary peritonitis caused by GAS among patients at Starship Children's Hospital, Auckland, New Zealand, during 2010-2022. We compare identified cases of GAS primary peritonitis to cases described in the existing pediatric literature. As rates of rates of invasive GAS increase globally, clinicians should be aware of this cause of unexplained pediatric acute abdomen.

Pediatric Staphylococcus aureus Bacteremia: Clinical Spectrum and Predictors of Poor Outcome.

BACKGROUND: Staphylococcus aureus is a common cause of bacteremia, yet the epidemiology and predictors of poor outcome remain inadequately defined in childhood. METHODS: ISAIAH (Invasive Staphylococcus aureus Infections and Hospitalizations in children) is a prospective, cross-sectional study of S. aureus bacteremia (SAB) in children hospitalized in Australia and New Zealand over 24 months (2017-2018). RESULTS: Overall, 552 SABs were identified (incidence 4.4/100 000/year). Indigenous children, those from lower socioeconomic areas and neonates were overrepresented. Although 90-day mortality was infrequent, one-third experienced the composite of: length of stay >30 days (26%), intensive care unit admission (20%), relapse (4%), or death (3%). Predictors of mortality included prematurity (adjusted odds ratio [aOR],16.8; 95% confidence interval [CI], 1.6-296.9), multifocal infection (aOR, 22.6; CI, 1.4-498.5), necrotizing pneumonia (aOR, 38.9; CI, 1.7-1754.6), multiorgan dysfunction (aOR, 26.5; CI, 4.1-268.8), and empiric vancomycin (aOR, 15.7; CI, 1.6-434.4); while infectious diseases (ID) consultation (aOR, 0.07; CI .004-.9) was protective. Neither MRSA nor vancomycin trough targets impacted survival; however, empiric vancomycin was associated with nephrotoxicity (OR, 3.1; 95% CI 1.3-8.1). CONCLUSIONS: High SAB incidence was demonstrated and for the first time in a pediatric setting, necrotizing pneumonia and multifocal infection were predictors of mortality, while ID consultation was protective. The need to reevaluate pediatric vancomycin trough targets and limit unnecessary empiric vancomycin exposure to reduce poor outcomes and nephrotoxicity is highlighted. One in 3 children experienced considerable SAB morbidity; therefore, pediatric inclusion in future SAB comparator trials is paramount to improve outcomes.

COVID-19 vaccination in children and adolescents aged 5 years and older undergoing treatment for cancer and non-malignant haematological conditions: Australian and New Zealand Children's Haematology/Oncology Group consensus statement.

INTRODUCTION: The Australian Technical Advisory Group on Immunisation and New Zealand Ministry of Health recommend all children aged ≥ 5 years receive either of the two mRNA COVID-19 vaccines: Comirnaty (Pfizer), available in both Australia and New Zealand, or Spikevax (Moderna), available in Australia only. Both vaccines are efficacious and safe in the general population, including children. Children and adolescents undergoing treatment for cancer and immunosuppressive therapy for non-malignant haematological conditions are particularly vulnerable, with an increased risk of severe or fatal COVID-19. There remains a paucity of data regarding the immune response to COVID-19 vaccines in immunosuppressed paediatric populations, with data suggestive of reduced immunogenicity of the vaccine in immunocompromised adults. RECOMMENDATIONS: Considering the safety profile of mRNA COVID-19 vaccines and the increased risk of severe COVID-19 in immunocompromised children and adolescents, COVID-19 vaccination is strongly recommended for this at-risk population. We provide a number of recommendations regarding COVID-19 vaccination in this population where immunosuppressive, chemotherapeutic and/or targeted biological agents are used. These include the timing of vaccination in patients undergoing active treatment, management of specific situations where vaccination is contraindicated or recommended under special precautions, and additional vaccination recommendations for severely immunocompromised patients. Finally, we stress the importance of upcoming clinical trials to identify the safest and most efficacious vaccination regimen for this population. CHANGES IN MANAGEMENT AS A RESULT OF THIS STATEMENT: This consensus statement provides recommendations for COVID-19 vaccination in children and adolescents aged ≥ 5 years with cancer and immunocompromising non-malignant haematological conditions, based on evidence, national and international guidelines and expert opinion. ENDORSED BY: The Australian and New Zealand Children's Haematology/Oncology Group.

Fatal hyperammonemia associated with disseminated Serratia marcescens infection in a pediatric liver transplant recipient.

Hyperammonemia is a rare and important complication post-liver transplantation. We review a case of a 5-month-old boy with biliary atresia who received a split liver transplant following a variceal bleed. The transplant was complicated by recurrent portal vein thrombosis. Colonized with Serratia marcescens pretransplant, he developed disseminated infection associated with very high levels of ammonia that led to his death. It is important to be aware of serum ammonia levels in patients with portal vein thrombosis, particularly in the setting of gastrointestinal bleeding and sepsis.

Hospital readmissions with acute infectious diseases in New Zealand children < 2 years of age.

BACKGROUND: Infectious diseases are the leading cause of hospital admissions in young children. Hospitalisation with an infectious disease is a recurrent event for some children. Our objective was to describe risk factors for infectious disease readmission following hospital admission with an infectious disease in the first two years of life. METHODS: We performed a national cohort study of New Zealand children, born 2005-2009, with an infectious disease admission before age 24 months. Children readmitted with an infectious disease within 12 months of the first infectious disease admission were identified. Every infectious disease admission was categorised as a respiratory, enteric, skin and soft tissue, urinary or other infection. Independent associations of demographic and child health factors with infectious disease readmission were determined using multiple variable logistic regression. RESULTS: From 2005 to 2011, there were 69,902 infectious disease admissions for 46,657 children less than two years old. Of these 46,657 children, 10,205 (22%) had at least one infectious disease readmission within 12 months of their first admission. The first infectious disease admission was respiratory (54%), enteric (15%), skin or soft tissue (7%), urinary (4%) or other (20%). Risk of infectious disease readmission was increased if the first infectious disease admission was respiratory (OR = 1.87, 95% CI 1.78-1.95) but not if it was in any other infectious disease category. Risk factors for respiratory infectious disease readmission were male gender, Pacific or Maori ethnicity, greater household deprivation, presence of a complex chronic condition, or a first respiratory infectious disease admission during autumn or of ≥3 days duration. Fewer factors (younger age, male gender, presence of a complex chronic condition) were associated with enteric infection readmission. The presence of a complex chronic condition was the only factor associated with urinary tract infection readmission and none of the factors were associated with skin or soft tissue infection readmission. CONCLUSIONS: In children less than two years old, infectious disease readmission risk is increased if the first infectious disease admission is a respiratory infectious disease but not if it is another infectious disease category. Risk factors for respiratory infectious disease readmission are different from those for other infectious disease readmissions.

Respiratory virus detection during hospitalisation for lower respiratory tract infection in children under 2 years in South Auckland, New Zealand.

AIM: To describe respiratory virus detection in children under 2 years of age in a population admitted with lower respiratory infection and to assess correlation with measures of severity. METHODS: Nasopharyngeal aspirates from infants admitted with lower respiratory tract infection (n = 1645) over a 3-year time period were tested by polymerase chain reaction. We collected epidemiological and clinical data on all children. We assessed the correlation of presence of virus with length of hospital stay, intensive care admission and consolidation on chest X-ray. RESULTS: Of the children admitted 34% were Maori, 43% Pacific and 75% lived in areas in the bottom quintile for socio-economic deprivation. A virus was found in 94% of those tested including 30% with multiple viruses. Picornavirus was present in 59% including 34% as the sole virus. Respiratory syncytial virus was found in 39%. Virus co-detection was not associated with length of stay, chest X-ray changes or intensive care unit admission. CONCLUSION: In this disadvantaged predominately Maori and Pacific population, picornavirus is commonly found as a sole virus, respiratory syncytial virus is frequent but immunisation preventable influenza is infrequent. We did not find that co-detection of viruses was linked to severity.

What is behind the ear drum? The microbiology of otitis media and the nasopharyngeal flora in children in the era of pneumococcal vaccination.

AIM: This study aims to describe the microbiology of middle ear fluid (MEF) in a cohort of children vaccinated with Streptococcus pneumoniae conjugate vaccine (PCV7) having ventilation tube insertion. Nasopharyngeal (NP) carriage of otopathogens in these children is compared with children without history of otitis media. METHODS: Between May and November 2011, MEF and NP samples from 325 children aged <3 years were collected in three major centres in New Zealand at the time of ventilation tube insertion. An age-matched non-otitis-prone comparison group of 137 children had NP samples taken. A questionnaire was completed by both groups. RESULTS: Immunisation coverage with at least one dose of PCV7 was 97%. Haemophilus influenzae was cultured in 19.4% of MEF and was polymerase chain reaction (PCR) positive in 43.4%. S. pneumoniae and Moraxella catarrhalis were cultured in <10% of MEF samples but were PCR positive for 23.1% and 38.7%, respectively. H. influenzae was the most common organism isolated from NP samples (60%) in the grommet group, while M. catarrhalis (56%) was the most common in the non-otitis prone group. S. pneumoniae was more commonly found in the nasopharynx of children with ear disease (41% vs. 29%). 19F was the most prominent S. pneumoniae serotype in NP samples of both groups, but no serotype dominated in MEF. Ninety-five per cent of H. influenzae isolates were confirmed to be non-typeable H. influenzae. CONCLUSION: In this cohort of children with established ear disease requiring surgical intervention, non-typeable H. influenzae is the dominant pathogen in both the nasopharynx and MEF.

Whole-of-Life Inclusion in Bayesian Adaptive Platform Clinical Trials.

Importance: There is a recognized unmet need for clinical trials to provide evidence-informed care for infants, children and adolescents. This Special Communication outlines the capacity of 3 distinct trial design strategies, sequential, parallel, and a unified adult-pediatric bayesian adaptive design, to incorporate children into clinical trials and transform this current state of evidence inequity. A unified adult-pediatric whole-of-life clinical trial is demonstrated through the Staphylococcus aureus Network Adaptive Platform (SNAP) trial. Observations: Bayesian methods provide a framework for synthesizing data in the form of a probability model that can be used in the design and analysis of a clinical trial. Three trial design strategies are compared: (1) a sequential adult-pediatric bayesian approach that involves a separate, deferred pediatric trial that incorporates existing adult trial data into the analysis model to potentially reduce the pediatric trial sample size; (2) a parallel adult-pediatric bayesian trial whereby separate pediatric enrollment occurs in a parallel trial, running alongside an adult randomized clinical trial; and (3) a unified adult-pediatric bayesian adaptive design that supports the enrollment of both children and adults simultaneously in a whole-of-life bayesian adaptive randomized clinical trial. The SNAP trial whole-of-life design uses a bayesian hierarchical model that allows information sharing (also known as borrowing) between trial age groups by linking intervention effects of children and adults, thereby improving inference in both groups. Conclusion and Relevance: Bayesian hierarchical models may provide more precision for estimates of safety and efficacy of treatments in trials with heterogenous populations compared to traditional methods of analysis. They facilitate the inclusion of children in clinical trials and a shift from children deemed therapeutic orphans to the vision of no child left behind in clinical trials to ensure evidence for clinical practice exists across the life course. The SNAP trial provides an example of a bayesian adaptive whole-of-life inclusion design that enhances trial population inclusivity and diversity overall, as well as generalizability and translation of findings into clinical practice.

COVID-19-related hospitalizations among Aotearoa, New Zealand children during the Omicron era of SARS-CoV-2.

Objectives: This multicenter cohort study describes Aotearoa New Zealand children hospitalized during the country's first wave of sustained SARS-CoV-2 transmission, Omicron variant. Methods: Children younger than 16 years, hospitalized for >6 hours with COVID-19 across New Zealand from January to May 2022 were included. Admissions for all Maori and Pacific and every second non-Maori non-Pacific children were selected to support equal explanatory power for ethnic grouping. Attribution of hospital admission, demography, clinical presentation, comorbidity, treatment, and outcome data were collected. Results: Of 444 hospitalizations of children positive for COVID-19, 292 (65.5%) from 290 children were considered admissions attributable to COVID-19. Of these admissions, 126 (43.4%) were aged under 1; 118 (40.7%), 99 (34.1%), and 87 (30.0%) were children of Maori, Pacific, and non-Maori non-Pacific ethnicity, respectively. Underlying respiratory disease was the most common comorbidity, present in 22 children (7.6%); 16 children (5.5%) were immunosuppressed. Median length of stay was 1 day (interquartile range 0.0-2.0). Four children received antiviral, 69 (24%) antibacterial, and 24 (8%) supplemental oxygen. Although eight children required intensive care, there were no deaths. Conclusions: Children hospitalized during the first significant wave of SARS-CoV-2 infection in New Zealand presented with a multi-system viral illness and rarely with severe disease.

Improved paediatric antimicrobial prescribing with a smartphone application: a before and after interventional study.

INTRODUCTION: Children have a high consumption of antimicrobials that require complicated decision-making by prescribers. Despite this, antimicrobial stewardship (AMS) interventions are often not translated into paediatric medicine. Script is a smartphone application (app) launched in Auckland, New Zealand to support decision-making for antimicrobial prescribers. The aim was to improve adherence to existing local clinical guidelines for both adult and paediatric infections. METHODS: Inpatient and emergency department antimicrobial prescriptions were prospectively collected and evaluated for guideline adherence. Baseline prescribing data were collected and compared with prescribing at 4 months and 1 year after the app was launched. Prescriptions were graded as 'appropriate' or 'inappropriate' by investigators. Grading was done blinded to timing of the prescription relative to the intervention. RESULTS: Following the launch of the Script app, guideline adherence significantly increased from 241 of 348 (69%) antimicrobial prescriptions graded as appropriate during the baseline period to 301 of 359 (83%) after 4 months (p<0.0001). This improvement from baseline was sustained at 1 year with 263 of 323 (81%) adherence (p<0.001). At 1 year, this improvement could be demonstrated separately for medical, surgical and emergency department prescriptions. CONCLUSION: There was a significant and sustained improvement in adherence to paediatric antimicrobial guidelines following the introduction of a prescribing support app. The need to seek guidance for antimicrobial doses due to the age-based and weight-based calculations in paediatrics may mean that AMS interventions such as decision support and prescribing tools are particularly well suited to paediatric prescribing.

Multisystem Inflammatory Syndrome in New Zealand Children.

New Zealand (NZ) initially adopted an elimination approach to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Pre-Omicron variant, the NZ pediatric population was immunologically naïve to SARS-CoV-2. This study, utilizing national data sources, describes the NZ incidence of multisystem inflammatory syndrome in children (MIS-C) following infection with the Omicron variant. MIS-C incidence was 1.03 of 100,000 age-specific population and 0.04 of 1000 recorded SARS-CoV-2 infections.

Whole genome sequencing and molecular epidemiology of paediatric Staphylococcus aureus bacteraemia.

OBJECTIVES: The role Staphylococcus aureus antimicrobial resistance genes and toxins play in disease severity, management and outcome in childhood is an emerging field requiring further exploration. METHODS: A prospective multisite study of Australian and New Zealand children hospitalised with S. aureus bacteraemia (SAB) occurred over 24 months (2017-2018). Whole genome sequencing (WGS) data were paired with clinical information from the ISAIAH cohort. RESULTS: 353 SAB isolates were sequenced; 85% methicillin-susceptible S. aureus ([MSSA], 301/353) and 15% methicillin-resistant S. aureus ([MRSA], 52/353). There were 92 sequence types (STs), most commonly ST5 (18%) and ST30 (8%), grouped into 23 clonal complexes (CCs), most frequently CC5 (21%) and CC30 (12%). MSSA comprised the majority of healthcare-associated SAB (87%, 109/125), with principal clones CC15 (48%, 11/21) and CC8 (33%, 7/21). Panton-Valentine leukocidin (PVL)-positive SAB occurred in 22% (76/353); predominantly MSSA (59%, 45/76), community-onset (92%, 70/76) infections. For community-onset SAB, the only microbiological independent predictor of poor outcomes was PVL positivity (aOR 2.6 [CI 1.0-6.2]). CONCLUSION: From this WGS paediatric SAB data, we demonstrate the previously under-recognized role MSSA has in harbouring genetic virulence and causing healthcare-associated infections. PVL positivity was the only molecular independent predictor of poor outcomes in children. These findings underscore the need for further research to define the potential implications PVL-producing strains may have on approaches to S. aureus clinical management.

Surveillance of pediatric parapneumonic effusion/empyema in New Zealand.

AIM: The incidence of childhood empyema has been increasing in some developed countries despite the introduction of pneumococcal vaccination. This study aimed to document the incidence, bacterial pathogens, and morbidity/mortality of parapneumonic effusion/empyema in New Zealand. METHODS: A prospective study of 102 children <15 years of age requiring hospitalization with parapneumonic effusion/empyema between May 1, 2014 and May 31, 2016 notified via the New Zealand Paediatric Surveillance Unit. Parapneumonic effusion/empyema was defined as pneumonia and pleural effusion persisting ≥7 days, and/or any pneumonia, and pleural effusion necessitating drainage. Notifying pediatricians completed standardized questionnaires. RESULTS: Annual pediatric parapneumonic effusion/empyema incidence was 5.6/100,000 (95% confidence interval [CI]: 4.7-6.9). Most children (80%) required surgical intervention and 31% required intensive care. A causative organism was identified in 71/102 (70%) cases. Although Staphylococcus aureus (25%) and Streptococcus pneumoniae (25%) infection rates were equal, prolonged hospitalization and intensive care admission were more common in children with S. aureus PPE/E. Maori and Pasifika children were over-represented at 2.2 and 3.5 times, their representation in the New Zealand pediatric population. Pneumococcal vaccination was incomplete, with only 61% fully immunized and 30% unimmunized. Haemophilus influenzae type b vaccine uptake was near complete at 89/94 (95%), with influenza immunization only 3/78 (4%). CONCLUSIONS: New Zealand has a high incidence of pediatric complicated parapneumonic effusion/empyema with significant morbidity. S. aureus was a significant cause of severe empyema in New Zealand, particularly for Maori and Pasifika children. Improvements in vaccine coverage are needed along with strategies to reduce S. aureus disease morbidity.

In vitro Inhibition of Clinical Isolates of Otitis Media Pathogens by the Probiotic Streptococcus salivarius BLIS K12.

Otitis media is a common childhood infection, frequently requiring antibiotics. With high rates of antibiotic prescribing and increasing antibiotic resistance, new strategies in otitis media prevention and treatment are needed. The aim of this study was to assess the in vitro inhibitory activity Streptococcus salivarius BLIS K12 against otitis media pathogens. Efficacy of the bacteriocin activity of S. salivarius BLIS K12 against the otitis media isolates was assessed using the deferred antagonism test. Overall, 48% of pathogenic isolates exhibited some growth inhibition by S. salivarius BLIS K12. S. salivarius BLIS K12 can inhibit the in vitro growth of the most common pathogens.

Impact of rotavirus vaccine on paediatric rotavirus hospitalisation and intussusception in New Zealand: A retrospective cohort study.

BACKGROUND: Rotavirus results in a significant burden of hospitalisations and deaths globally. Rotavirus vaccine has been used in New Zealand since July 2014. The aim of this study was to assess the safety and effectiveness of RotaTeq® vaccine in New Zealand between 2006 and 2016. METHODS: A national cohort study of 723,695 children aged less than 6 years was carried out using linked administrative datasets. Study outcomes were hospitalisation for intussusception, rotavirus, and all-cause gastroenteritis. Intussusception hospitalisation rates were calculated from 2006 to 2016, and rotavirus and all-cause gastroenteritis hospitalisation rates from 2011 to 2016. We examined the effect of RotaTeq® vaccination on rotavirus and all-cause gastroenteritis hospitalisation rates using Poisson regression. Adjusted incidence rate ratios controlled for sex, year of birth, ethnicity, socioeconomic deprivation, and district health board area. RESULTS: Significant reductions in the incidence of rotavirus hospitalisation were seen in all age groups, ethnicities, and deprivation following the introduction of RotaTeq®. There was a 92.6% reduction in hospitalisation incidence in the vaccinated cohort (p < 0.0001). There was also a 48% reduction in all-cause gastroenteritis hospitalisation incidence in the vaccinated cohort (p < 0.0001). The average annual intussusception rate in children aged less than 3 years was 26.2 per 100,000, with no significant change over time (p = 0.847). CONCLUSIONS: In New Zealand the introduction of RotaTeq® resulted in a significant reduction in rotavirus hospitalisation, and a halving in all-cause gastroenteritis hospitalisation. There has been no change in the overall incidence of intussusception or clear change in patterns of cases, although intussusception cases did occur within risk period immediately post vaccine.

Suboptimal performance of rotavirus testing in a vaccinated community population should prompt laboratories to review their rotavirus testing algorithms in response to changes in disease prevalence.

Rotavirus vaccine has reduced disease prevalence in many countries. Consequently, we aimed to assess the reliability of a rotavirus immunoassay in the community population of Auckland and Northland, New Zealand. Between 22 October 2015 and 31 December 2016, 2873 fecal samples were tested by enzyme immunoassay (EIA, Rotascreen II, Microgen, UK) from 2748 patients (median age 8 years, range 0-101 years). Eighty-nine (3.1%) samples were reactive; 86 samples were tested by a second method. Rotavirus was confirmed in 49/86 (57%). Positive rotavirus EIAs were more likely to be confirmed in samples from cases ≥1 year of age (positive predictive value [PPV] 61%, 95% confidence interval [CI] 50-72%, P = 0.049) and in spring/summer (PPV 67%, 95% CI 55-78%, P = 0.003). Reactive rotavirus tests required confirmatory testing regardless of demographic, vaccine, or seasonal factors; a review of rotavirus testing algorithms may be necessary in other vaccinated community populations.

PCV7- and PCV10-Vaccinated Otitis-Prone Children in New Zealand Have Similar Pneumococcal and Haemophilus influenzae Densities in Their Nasopharynx and Middle Ear.

Otitis media (OM) is a major reason for antibiotic consumption and surgery in children. Nasopharyngeal carriage of otopathogens, Streptococcus pneumoniae and nontypeable Haemophilus influenzae (NTHi), is a prerequisite for development of OM, and increased nasopharyngeal otopathogen density correlates with disease onset. Vaccines can reduce or eliminate otopathogen carriage, as demonstrated for pneumococcal serotypes included in pneumococcal conjugate vaccines (PCV). The 10-valent PCV (PCV10) includes an NTHi carrier protein, and in 2011 superseded 7-valent PCV on the New Zealand Immunisation Program. Data are conflicting on whether PCV10 provides protection against NTHi carriage or disease. Assessing this in otitis-prone cohorts is important for OM prevention. We compared otopathogen density in the nasopharynx and middle ear of New Zealand PCV7-vaccinated and PCV10-vaccinated otitis-prone and non-otitis-prone children to determine PCV10 impact on NTHi and S. pneumoniae carriage. We applied qPCR to specimens collected from 217 PCV7-vaccinated children (147 otitis-prone and 70 non-otitis-prone) and 240 PCV10-vaccinated children (178 otitis-prone and 62 non-otitis-prone). After correcting for age and day-care attendance, no difference was observed between NTHi density in the nasopharynx of PCV7-vaccinated versus PCV10-vaccinated otitis-prone (p = 0.563) or non-otitis-prone (p = 0.513) children. In contrast, pneumococcal nasopharyngeal density was higher in PCV10-vaccinated otitis-prone children than PCV7-vaccinated otitis-prone children (p = 0.003). There was no difference in otopathogen density in middle ear effusion from PCV7-vaccinated versus PCV10-vaccinated otitis-prone children (NTHi p = 0.918; S. pneumoniae p = 0.415). When pneumococcal carriage was assessed by vaccine serotypes (VT) and non-vaccine serotypes (NVT), there was no difference in VT density (p = 0.546) or NVT density (p = 0.315) between all PCV7-vaccinated versus all PCV10-vaccinated children. In summary, PCV10 did not reduce NTHi density in the nasopharynx or middle ear, and was associated with increased pneumococcal nasopharyngeal density in otitis-prone children in New Zealand. Development of therapies that prevent or reduce otopathogen colonisation density in the nasopharynx are warranted to reduce the burden of OM.

Rotavirus Infection in the Auckland Region After the Implementation of Universal Infant Rotavirus Vaccination: Impact on Hospitalizations and Laboratory Implications.

BACKGROUND: In July 2014, New Zealand introduced universal infant vaccination with RotaTeq (Merk & Co.) administered as 3 doses at 6 weeks, 3 and 5 months of age. We sought to assess the impact of rotavirus vaccination on gastroenteritis (GE) hospitalizations in the greater Auckland region and analyze changes in rotavirus testing in the period around vaccine introduction. METHODS: Hospitalizations, laboratory testing rates and methods were compared between the pre-vaccine period (2009-2013), post-vaccine period (January 2015 to December 2015) and year of vaccine introduction (2014). RESULTS: There was a 68% decline in rotavirus hospitalizations of children <5 years of age after vaccine introduction (from 258/100,000 to 83/100,000) and a 17% decline in all-cause gastroenteritis admissions (from 1815/100,000 to 1293/100,000). Reductions were also seen in pediatric groups too old to have received vaccine. Despite these changes, rotavirus testing rates in our region remained static in the year after vaccine introduction compared with the 2 prior years, and after vaccine introduction, we observed a high rate of false positives 19/58 (33%) in patients with reactive rotavirus tests. CONCLUSIONS: Rotavirus vaccine has had a significant early impact on gastroenteritis hospitalizations for children in the Auckland region. However, continued rotavirus testing at pre-vaccine rates risks generating false positive results. Laboratories and clinicians should consider reviewing their testing algorithms before vaccine introduction.

Epidemiology of intussusception in New Zealand pre-rotavirus vaccination.

AIMS: To describe the epidemiology of intussusception in New Zealand children aged 0-36 months prior to the introduction of routine rotavirus vaccination. METHODS: ICD-10 coding data from the New Zealand National Minimum Data Set (NMDS) was used to identify all cases of intussusception in children aged 0-36 months between January 1998 and December 2013. These data were linked with birth data from the New Zealand census. Population incidence rates of intussusception were calculated, and demographic characteristics described. RESULTS: Over the 16-year study period, there were 794 cases of intussusception. The majority (56%) occurred in the first year of life (age adjusted incidence rate 56.1/100,000 child-years, 95% confidence interval (CI) 41.7-71.2). Intussusception occurred more frequently in males (36.4/100,000 (95% CI 24.6-48.2) versus 19.5/100,000 (95% CI 10.8-28.1, p<0.001)). There was no difference in intussusception incidence between ethnic groups, although cases occurred at a younger age in Maori and Pacific infants compared to Asian and other ethnicities (Pacific median 7.5 months (interquartile range 5.9-11.6), Maori 7.8 months (IQR 5.5-12.3), European 9.2 months (IQR 5.8-15.8), Other Ethnicity 10.2 months (IQR 8.2-12.3), Asian 10.5 months (IQR 7.0-17.1 )). There was a weak seasonal trend with incidence troughs in January and July, and corresponding peaks in March and September. There was wide variation in presentation rates across District Health Board (DHB) regions, with a national average of 18.0/100,000 child-years (95% CI 9.7-26.3). Most patients were admitted on a single occasion to a single hospital for treatment (81%). CONCLUSIONS: This study updates background incidence rates of intussusception prior to the introduction of a national rotavirus vaccination programme in July 2014. It identifies a trend of earlier intussusception in Maori and Pacific infants; the relationship between earlier intussusception and the risk of vaccine-associated events is unknown.

Pneumococcal vaccine impact on otitis media microbiology: A New Zealand cohort study before and after the introduction of PHiD-CV10 vaccine.

UNLABELLED: We compared the microbiology of middle ear fluid (MEF) in two cohorts of children having ventilation tube (VT) insertion; the first in the era of 7-valent Streptococcus pneumoniae conjugate vaccine (PCV7) and the second following introduction of the ten-valent pneumococcal vaccine (PHiD-CV10). METHODS: During 2011 (Phase 1) and again in 2014 (Phase 2) MEF and NP samples from 325 children and 319 children were taken at the time of VT insertion. A matched comparison group had NP swabs collected with 137 children (Phase 1) and 154 (Phase 2). Culture was performed on all NP and MEF samples with further molecular identification of Haemophilus species, serotyping of S. pneumoniae, and polymerase chain reaction (PCR) testing on all MEF samples. RESULTS: In Phase 2 immunisation coverage with ⩾3 doses of PHiD-CV10 was 93%. The rate and ratios of culture and molecular detection of the 3 main otopathogens was unchanged between Phase 1 and Phase 2 in both MEF and NP. Haemophilus influenzae was cultured in one quarter and detected by PCR in 53% of MEF samples in both time periods. S. pneumoniae and Moraxella catarrhalis were cultured in up to 13% and detected by PCR in 27% and 40% respectively of MEF samples. H. influenzae was the most common organism isolated from NP samples (61%) in the children undergoing VT surgery whilst M. catarrhalis (49%) was the most common in the non-otitis prone group. 19A was the most prominent S. pneumoniae serotype in both MEF and NP samples in Phase 2. Of Haemophilus isolates, 95% were confirmed to be non-typeable H. influenzae (NTHi) over both time periods. CONCLUSION: Following implementation of PHiD-CV10 in New Zealand, there has been no significant change in the 3 major otopathogens in NP or MEF in children with established ear disease. For these children non-typeable H. influenzae remains the dominant otopathogen detected.