Cohorting children in a childcare setting: a strategy to reduce SARS-CoV-2 Delta transmission, August-September 2021.

Background: Childcare centres can be high-risk settings for SARS-CoV-2 transmission due to age, vaccination status, and infection control challenges. We describe the epidemiology and clinical characteristics of a childcare SARS-CoV-2 Delta outbreak. When the outbreak occurred, little was known about the transmission dynamics of SARS-CoV-2 ancestral and Delta strains among children. Vaccinations for coronavirus disease 2019 (COVID-19) were not mandatory for childcare staff, and children (< 12 years) were ineligible. Methods: A retrospective cohort design of childcare attendees was used to investigate age-cohorts exposure and transmission of SARS-CoV-2. We defined a case as a person who tested positive to SARS-CoV-2; we defined a close contact as a person who attended the childcare during 16-20 August 2021. Childcare centre exposures were defined by three cohorts: younger children (0-< 2.5 years) with designated staff; older children (2.5-5 years) with designated staff; and a staff-only group that moved between both age cohorts. We calculated the number and proportion of SARS-CoV-2 Delta infections, symptom profile and severity in children and adults, secondary attack rates, and relative risks (RR) with 95% confidence intervals (CIs) to compare age-cohort exposures and SARS-CoV-2 infection. Results: There were 38 outbreak cases that tested positive to SARS-CoV-2 Delta infection, comprising one primary case, 11 childcare attendees and 26 household members. Child attendees were in two non-interacting groups, 0-< 2.5 years and 2.5-5 years, with designated staff, separate rooms, and independent ventilation. The greatest risk of infection to childcare attendees was in the < 2.5 years age cohort which had a secondary attack rate of 41% and were five times more likely to be infected with SARS-CoV-2 (RR = 5.73; 95% CI: 1.37-23.86; p ≤ 0.01). No identified transmission (n = 0/21) occurred in the ≥ 2.5 years age cohort. Conclusion: Young children play an important role in SARS-CoV-2 Delta transmission to their peers and staff in childcare settings and to household members. Cohorting may be effective at limiting the propagation of SARS-CoV-2 in childcare settings. These findings highlight a need for multi-layered mitigation strategies and implementation support to manage respiratory infection control challenges at childcares. If prevention measures are not in place, this may facilitate ongoing transmission in these settings and into the broader community.

The changing epidemiology of shigellosis in Australia, 2001-2019.

Shigellosis is an increasing cause of gastroenteritis in Australia, with prolonged outbreaks reported in remote Aboriginal and Torres Strait Islander (hereafter "First Nations") communities and among men who have sex with men (MSM) in major cities. To determine associations between Shigella species and demographic and geographic factors, we used multivariate negative binomial regression to analyse national case notifications of shigellosis from 2001 to 2019. Between 2001 and 2019, Australian states and territories reported 18,363 shigellosis cases to the National Notifiable Diseases Surveillance System (NNDSS), of which age, sex and organism information were available for >99% (18,327/18,363) of cases. Of the cases included in our analysis, 42% (7,649/18,327) were S. sonnei, 29% (5,267/18,327) were S. flexneri, 1% (214/18,327) were S. boydii, less than 1% (87/18,327) were S. dysenteriae, and species information was unknown for 28% (5,110/18,327) of cases. Males accounted for 54% (9,843/18,327) of cases, and the highest proportion of cases were in children aged 0-4 years (19%; 3,562/18,327). Crude annual notification rates ranged from 2.2 cases per 100,000 in 2003 and 2011 to 12.4 cases per 100,000 in 2019. Nationally, notification rates increased from 2001 to 2019 with yearly notification rate ratios of 1.04 (95% CI 1.02-1.07) for S. boydii and 1.05 (95% CI 1.04-1.06) for S. sonnei. Children aged 0-4 years had the highest burden of infection for S. flexneri, S. sonnei and S. boydii; and males had a higher notification rate for S. sonnei (notification rate ratio 1.24, 95% CI 1.15-1.33). First Nations Australians were disproportionately affected by shigellosis, with the notification rate in this population peaking in 2018 at 92.1 cases per 100,000 population. Over the study period, we also observed a shift in the testing method used to diagnose shigellosis, with culture independent diagnostic testing (CIDT) increasing from 2014; this also coincided with an increase in notifications of untyped Shigella. This change in testing methodology may have contributed to the observed increase in shigellosis notifications since 2014, with CIDT being more sensitive than culture dependent testing methods. The findings of this study provide important insights into the epidemiological characteristics of shigellosis in Australia, including identification of high-risk groups. This can be used to inform public health prevention and control strategies, such as targeted communication programs in First Nations communities and places with high levels of interaction between young children, such as childcare centres. Our study findings also highlight the implications of culture independent testing on shigellosis surveillance, particularly a reduction in the availability of species level information. This emphasises the continued importance of culture dependant testing for national surveillance of shigellosis.

Multistate Outbreak of Salmonella enterica Serovar Heidelberg with Unidentified Source, Australia, 2018-2019.

We report a multistate Salmonella enterica serovar Heidelberg outbreak in Australia during 2018-2019. Laboratory investigation of cases reported across 5 jurisdictions over a 7-month period could not identify a source of infection but detected indicators of severity and invasiveness. The hospitalization rate of 36% suggested a moderately severe clinical picture.

COVID-19 in health care workers, Australia 2020.

BACKGROUND: Health care workers are at increased risk of SARS-CoV-2 infection due to potential exposure to patients or staff in health care settings. Australian health care services and health care workers experienced intense pressure to prepare for and respond to SARS-CoV-2 infections. We summarise national data on health care worker infections and associated outbreaks during 2020. METHODS: We collected aggregated data on infected health care workers and outbreaks in health care facilities from all jurisdictions. Health care workers working solely in residential aged care and outbreaks in residential aged care facilities were excluded. Jurisdictions provided data on the number of health care setting outbreaks, confirmed cases, hospitalisation, source of infection, and health care worker role. We analysed data for two periods that aligned with two distinct peaks in the epidemic relative to 1 June 2020, referred to here as the first wave (23 January - 31 May 2020) and the second wave (1 June - 18 September 2020). RESULTS: Jurisdictions reported a total of 2,163 health care worker infections with SARS-CoV-2 during the surveillance period. Source of acquisition was known for 81.0% of cases (1,667/2,059). The majority of cases in the first wave were acquired overseas, shifting to locally-acquired cases in the second wave. The odds of infection in the second wave compared to the first wave were higher for nurses/midwives (odds ratio, OR: 1.61; 95% confidence interval (95% CI): 1.32-2.00), lower for medical practitioners (OR: 0.36; 95% CI: 0.28-0.47) and did not differ for 'other' health care workers (OR: 1.07; 95% CI: 0. 87-1.32). The odds of infection in the second wave were higher in a health care setting (OR: 1.76; 95% CI: 1.28-2.41) than in the community. There were 120 outbreaks in health care settings with 1,428 cases, of which 56.7% (809/1,428) were health care workers. The majority (88/120; 73.8%) of outbreaks in health care settings occurred in the second wave of the epidemic, with 90.9% of these (80/88) occurring in Victoria. CONCLUSIONS: In the second wave of the epidemic, when there was heightened community transmission, health care workers were more likely to be infected in the workplace. Throughout the epidemic, nurses were more likely to be infected than staff in other roles.

Monitoring the incidence and causes of disease potentially transmitted by food in Australia: Annual report of the OzFoodNet network, 2016.

ABSTRACT: In 2016, a total of 44,455 notifications of enteric diseases potentially related to food were received by state and territory health departments in Australia. Consistent with previous years, campylobacteriosis (n = 24,171) and salmonellosis (n = 18,060) were the most frequently-notified infections. Notable increases in incidence were observed for shiga toxin-producing Escherichia coli (n = 343; 166% increase), shigellosis (n = 1,408; 93% increase), campylobacteriosis (33% increase) and salmonellosis (30% increase) when compared with the historical five-year mean. The extent to which the introduction of culture-independent testing as a method of diagnosis has contributed to these increases remains unclear. In total, 188 gastrointestinal outbreaks, including 177 foodborne outbreaks, were reported in 2016. The 11 non-foodborne outbreaks were due to environmental or probable environmental transmission (nine outbreaks) and animal-to-person or probable animal-to-person transmission (two outbreaks). No outbreaks of waterborne or probable waterborne transmission were reported in 2016. Foodborne outbreaks affected 3,639 people, resulting in at least 348 hospital admissions and four deaths. Eggs continue to be a source of Salmonella Typhimurium infection across the country: 35 egg-related outbreaks, affecting approximately 510 people, were reported across six jurisdictions in 2016. Three large multi-jurisdictional Salmonella outbreaks associated with mung bean sprouts (n = 419 cases); bagged salad products (n = 311 cases); and rockmelons (n = 144 cases) were investigated in 2016. These outbreaks highlight the risks associated with fresh raw produce and the ongoing need for producers, retailers and consumers to implement strategies to reduce potential Salmonella contamination.

The effect of COVID-19 public health measures on nationally notifiable diseases in Australia: preliminary analysis.

ABSTRACT: Since the introduction of COVID-19-related public health measures, notifications for most nationally notifiable diseases have declined when compared to previous years. Physical distancing, travel restrictions, and emphasis on hygiene are likely to have affected the number of expected notifications, with the greatest reductions observed among disease spread via person-to-person contact such as influenza, and among overseas-acquired infections such as dengue virus and measles. However, quantifying the magnitude of the effect of COVID-19 public health measures on communicable diseases in Australia will be difficult, due to confounding factors such as: changes in testing priorities in laboratories; diversion of resources to the COVID-19 response; changes in health-seeking behaviours; greater utilisation of telehealth practices; and financial impacts such as income loss and ability to afford healthcare. It is considered likely that these other factors will have also impacted notification numbers.

High COVID-19 attack rate among attendees of wedding events in Bali, Indonesia, March 2020.

BACKGROUND: Large gatherings are associated with the spread of coronavirus 2019 disease (COVID-19); however, transmission dynamics are not well understood. We investigated a cluster of COVID-19 cases in returning Australian residents who attended wedding events in Bali, Indonesia, during 15- 21 March 2020. Attendees participated in various social events and were in close proximity, providing multiple opportunities for transmission. METHODS: We conducted a retrospective cohort study of the 41 attendees, of whom 17 participated in a structured interview that included history of illness, risk exposures and event attendance. We obtained data for the remaining 24 participants through corroborative histories and public health unit case investigations. RESULTS: COVID-19 was identified in 56% of attendees (23/41), with illness onset between 21 March and 2 April 2020. One secondary case was identified in a household contact of an attendee. The median age of cases was 31 years (range 3-64). One case was hospitalised and did not require critical care. There were no deaths. No cases occurred among six attendees who left prior to the actual wedding day. Guests attended multiple events and participated in high-risk transmission behaviours such as shaking hands, kissing, dancing, sharing drinks and sharing shisha (water pipes). Attack rates ranged from 64% to 87% for different exposures. We could not identify a single risk exposure that accounted for all cases; it is therefore likely there were multiple episodes of transmission. CONCLUSION: Our investigation identified a high attack rate of COVID-19 among a cohort of wedding event attendees. Attendees engaged in close physical contact, shared drinks and shisha, and were in close proximity during the wedding events, which may have contributed to the high attack rate. This outbreak highlights the significant role social events can play in transmission of COVID-19 and underscores why it is important to limit gatherings and close physical contact to control the spread of the virus.

Characteristics of Campylobacter Gastroenteritis Outbreaks in Australia, 2001 to 2016.

Campylobacter spp. are a globally important cause of bacterial gastroenteritis, with Australia experiencing higher rates of illness than many comparable high-income countries. Despite the high disease incidence, outbreaks of campylobacteriosis in Australia are infrequently detected and reported. We examined the epidemiology of Campylobacter outbreaks in Australia, with particular emphasis on assessing transmission routes and evidence as reported during public health investigations. A national register of enteric and foodborne disease outbreaks was used to summarize data on all Campylobacter outbreaks reported in Australia between 2001 and 2016. Outbreak data were reviewed and analyzed for trends over time. Additional information was sought from state and territory epidemiologists, to validate transmission routes. A total of 84 Campylobacter outbreaks were reported, with 51 (61%) being classified as foodborne. Specific food vehicles were identified for 33 (65%) outbreaks, with 28 (85%) implicating chicken or chicken-containing dishes. Although no increase in the proportion of foodborne Campylobacter outbreaks was observed, examination of specific food vehicles demonstrated a significant increase in outbreaks because of poultry-liver containing foods (p = 0.04). One quarter of all 1042 outbreak-associated cases occurred in aged-care facilities (ACFs), including 17 associated hospitalizations and three deaths. After review of evidence data, 23 outbreaks (27%) were determined to have an unknown route of transmission, including 10 (43%) outbreaks occurring in ACFs. Campylobacter spp. remain a less commonly reported cause of gastroenteritis outbreaks in Australia. Although many reported outbreaks can be linked to foodborne transmission, over a quarter were unable to identify either a food vehicle or transmission source, particularly for outbreaks occurring in aged care. Increased efforts to improve evidence collection and understanding of transmission dynamics for outbreaks of campylobacteriosis, particularly in aged care, are required.

The Effects of Preprocessing Strategies for Pediatric Cochlear Implant Recipients.

BACKGROUND: Cochlear implants (CIs) have been shown to improve children's speech recognition over traditional amplification when severe-to-profound sensorineural hearing loss is present. Despite improvements, understanding speech at low-level intensities or in the presence of background noise remains difficult. In an effort to improve speech understanding in challenging environments, Cochlear Ltd. offers preprocessing strategies that apply various algorithms before mapping the signal to the internal array. Two of these strategies include Autosensitivity Control™ (ASC) and Adaptive Dynamic Range Optimization (ADRO(®)). Based on the previous research, the manufacturer's default preprocessing strategy for pediatrics' everyday programs combines ASC + ADRO(®). PURPOSE: The purpose of this study is to compare pediatric speech perception performance across various preprocessing strategies while applying a specific programming protocol using increased threshold levels to ensure access to very low-level sounds. RESEARCH DESIGN: This was a prospective, cross-sectional, observational study. Participants completed speech perception tasks in four preprocessing conditions: no preprocessing, ADRO(®), ASC, and ASC + ADRO(®). STUDY SAMPLE: Eleven pediatric Cochlear Ltd. CI users were recruited: six bilateral, one unilateral, and four bimodal. INTERVENTION: Four programs, with the participants' everyday map, were loaded into the processor with different preprocessing strategies applied in each of the four programs: no preprocessing, ADRO(®), ASC, and ASC + ADRO(®). DATA COLLECTION AND ANALYSIS: Participants repeated consonant-nucleus-consonant (CNC) words presented at 50 and 70 dB SPL in quiet and Hearing in Noise Test (HINT) sentences presented adaptively with competing R-Space(TM) noise at 60 and 70 dB SPL. Each measure was completed as participants listened with each of the four preprocessing strategies listed above. Test order and conditions were randomized. A repeated-measures analysis of was used to compare each preprocessing strategy for the group. Critical differences were used to determine significant score differences between each preprocessing strategy for individual participants. RESULTS: For CNC words presented at 50 dB SPL, the group data revealed significantly better scores using ASC + ADRO(®) compared to all other preprocessing conditions while ASC resulted in poorer scores compared to ADRO(®) and ASC + ADRO(®). Group data for HINT sentences presented in 70 dB SPL of R-Space(TM) noise revealed significantly improved scores using ASC and ASC + ADRO(®) compared to no preprocessing, with ASC + ADRO(®) scores being better than ADRO(®) alone scores. Group data for CNC words presented at 70 dB SPL and adaptive HINT sentences presented in 60 dB SPL of R-Space(TM) noise showed no significant difference among conditions. Individual data showed that the preprocessing strategy yielding the best scores varied across measures and participants. CONCLUSIONS: Group data reveal an advantage with ASC + ADRO(®) for speech perception presented at lower levels and in higher levels of background noise. Individual data revealed that the optimal preprocessing strategy varied among participants, indicating that a variety of preprocessing strategies should be explored for each CI user considering his or her performance in challenging listening environments.

Music perception and appraisal: cochlear implant users and simulated cochlear implant listening.

BACKGROUND: The inability to hear music well may contribute to decreased quality of life for cochlear implant (CI) users. Researchers have reported recently on the generally poor ability of CI users to perceive music, and a few researchers have reported on the enjoyment of music by CI users. However, the relation between music perception skills and music enjoyment is much less explored. Only one study has attempted to predict CI users' enjoyment and perception of music from the users' demographic variables and other perceptual skills (Gfeller et al, 2008). Gfeller's results yielded different predictive relationships for music perception and music enjoyment, and the relationships were weak, at best. PURPOSE: The first goal of this study is to clarify the nature and relationship between music perception skills and musical enjoyment for CI users, by employing a battery of music tests. The second goal is to determine whether normal hearing (NH) subjects, listening with a CI simulation, can be used as a model to represent actual CI users for either music enjoyment ratings or music perception tasks. RESEARCH DESIGN: A prospective, cross-sectional observational study. Original music stimuli (unprocessed) were presented to CI users, and music stimuli processed with CI-simulation software were presented to 20 NH listeners (CIsim). As a control, original music stimuli were also presented to five other NH listeners. All listeners appraised 24 musical excerpts, performed music perception tests, and filled out a musical background questionnaire. Music perception tests were the Appreciation of Music in Cochlear Implantees (AMICI), Montreal Battery for Evaluation of Amusia (MBEA), Melodic Contour Identification (MCI), and University of Washington Clinical Assessment of Music Perception (UW-CAMP). STUDY SAMPLE: Twenty-five NH adults (22-56 yr old), recruited from the local and research communities, participated in the study. Ten adult CI users (46-80 yr old), recruited from the patient population of the local adult cochlear implant program, also participated in this study. DATA COLLECTION AND ANALYSIS: Musical excerpts were appraised using a seven-point rating scale, and music perception tests were scored as designed. Analysis of variance was performed on appraisal ratings, perception scores, and questionnaire data with listener group as a factor. Correlations were computed between musical appraisal ratings and perceptual scores on each music test. RESULTS: Music is rated as more enjoyable by CI users than by the NH listeners hearing music through a simulation (CIsim), and the difference is statistically significant. For roughly half of the music perception tests, there are no statistically significant differences between the performance of the CI users and of the CIsim listeners. Generally, correlations between appraisal ratings and music perception scores are weak or nonexistent. CONCLUSIONS: NH adults listening to music that has been processed through a CI-simulation program are a reasonable model for actual CI users for many music perception skills, but not for rating musical enjoyment. For CI users, the apparent independence of music perception skills and music enjoyment (as assessed by appraisals) indicates that music enjoyment should not be assumed and should be examined explicitly.