The Australian First Few X (FFX) Household Transmission Project for COVID-19 was the first prospective, multi-jurisdictional study of its kind in Australia. The project was undertaken as a ...partnership between federal and state health departments and the Australian Partnership for Preparedness Research on Infectious Disease Emergencies (APPRISE) and was active from April to October 2020.
We aimed to identify and explore the challenges and strengths of the Australian FFX Project to inform future FFX study development and integration into pandemic preparedness plans. We asked key stakeholders and partners involved with implementation to identify and rank factors relating to the strengths and challenges of project implementation in two rounds of modified Delphi surveys. Key representatives from jurisdictional health departments were then interviewed to contextualise findings within public health processes and information needs to develop a final set of recommendations for FFX study development in Australia.
Four clear recommendations emerged from the evaluation. Future preparedness planning should aim to formalise and embed partnerships between health departments and researchers to help better integrate project data collection into core public health surveillance activities. The development of functional, adaptable protocols with pre-established ethics and governance approvals and investment in national data infrastructure were additional priority areas noted by evaluation participants.
The evaluation provided a great opportunity to consolidate lessons learnt from the Australian FFX Household Transmission Project. The developed recommendations should be incorporated into future pandemic preparedness plans in Australia to enable effective implementation and increase local utility and value of the FFX platform within emergency public health response.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Prevalence of impetigo (skin sores) remains high in remote Australian Aboriginal communities, Fiji, and other areas of socio-economic disadvantage. Skin sore infections, driven primarily in these ...settings by Group A Streptococcus (GAS) contribute substantially to the disease burden in these areas. Despite this, estimates for the force of infection, infectious period and basic reproductive ratio-all necessary for the construction of dynamic transmission models-have not been obtained. By utilising three datasets each containing longitudinal infection information on individuals, we estimate each of these epidemiologically important parameters. With an eye to future study design, we also quantify the optimal sampling intervals for obtaining information about these parameters. We verify the estimation method through a simulation estimation study, and test each dataset to ensure suitability to the estimation method. We find that the force of infection differs by population prevalence, and the infectious period is estimated to be between 12 and 20 days. We also find that optimal sampling interval depends on setting, with an optimal sampling interval between 9 and 11 days in a high prevalence setting, and 21 and 27 days for a lower prevalence setting. These estimates unlock future model-based investigations on the transmission dynamics of skin sores.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
ABSTRACT Understanding the clinical spectrum of SARS‐CoV‐2 infection, including the asymptomatic fraction, is important as asymptomatic individuals are still able to infect other individuals and ...contribute to ongoing transmission. The WHO Unity Household transmission investigation (HHTI) protocol provides a platform for the prospective and systematic collection of high‐quality clinical, epidemiological, serological and virological data from SARS‐CoV‐2 confirmed cases and their household contacts. These data can be used to understand key severity and transmissibility parameters—including the asymptomatic proportion—in relation to local epidemic context and help inform public health response. We aimed to estimate the asymptomatic proportion of SARS‐CoV‐2 Omicron variant infections in Unity‐aligned HHTIs. We conducted a systematic review and meta‐analysis in alignment with the PRISMA 2020 guidelines and registered our systematic review on PROSPERO (CRD42022378648). We searched EMBASE, Web of Science, MEDLINE and bioRxiv and medRxiv from 1 November 2021 to 22 August 2023. We identified 8368 records, of which 98 underwent full text review. We identified only three studies for data extraction, with substantial variation in study design and corresponding estimates of the asymptomatic proportion. As a result, we did not generate a pooled estimate or I 2 metric. The limited number of quality studies that we identified highlights the need for improved preparedness and response capabilities to facilitate robust HHTI implementation, analysis and reporting, to better inform national, regional and global risk assessments and policymaking.
Background Impetigo or skin sores are estimated to affect >162 million people worldwide. Detailed descriptions of the anatomical location of skin sores are lacking. Methods We used prospectively ...collected data from a randomised control trial of treatments for impetigo in Aboriginal children in Australia. We generated heat-map distributions of skin sores on the human body from 56 predefined anatomical locations and stratified skin sore distribution by sex, age, causative pathogen and co-infection with scabies, tinea and head lice. We compared the distribution of sores between males and females, between sores with only Streptococcus pyogenes and sores with only Staphylococcus aureus; and across age groups with a Fisher's exact test. Results There were 663 episodes of impetigo infections among 508 children enrolled in the trial. For all 663 episodes, the lower limbs were the most affected body sites followed by the distal upper limbs, face and scalp. On the anterior surface of the body, the pre-tibial region was the most affected while on the posterior surface, the dorsum of the hands and calves predominated. There was no observable difference between males and females in distribution of sores. Children up to 3 years of age were more likely to have sores on the upper posterior lower limbs and scalp than older age groups, with the distribution of sores differing across age groups (p = 3 x 10.sup.-5 ). Sores from which only Staphylococcus aureus was cultured differed in distribution to those with only Streptococcus pyogenes cultured (p = 3 x 10.sup.-4 ) and were more commonly found on the upper posterior lower limbs. Conclusions Skin sores were predominantly found on exposed regions of the lower leg and distal upper limbs. The distribution of sores varied by age group and pathogen. These results highlight key areas of the body for clinicians to pay attention to when examining children for skin sores.
First Few "X" (FFX) studies provide a platform to collect the required epidemiological, clinical and virological data to help address emerging information needs about the COVID-19 pandemic.
We ...adapted the WHO FFX protocol for COVID-19 to understand severity and household transmission dynamics in the early stages of the pandemic in Australia. Implementation strategies were developed for participating sites; all household members were followed for 14 days from case identification. Household contacts completed symptom diaries and had multiple respiratory swabs taken irrespective of symptoms. We modelled the spread of COVID-19 within households using a susceptible-exposed-infectious-recovered-type model, and calculated the household secondary attack rate and key epidemiological parameters.
96 households with 101 cases and 286 household contacts were recruited into the study between April-October 2020. Forty household contacts tested positive for SARS-CoV-2 in the study follow-up period. Our model estimated the household secondary attack rate to be 15% (95% CI 8-25%), which scaled up with increasing household size. Our findings suggest children were less infectious than their adult counterparts but were also more susceptible to infection.
Our study provides important baseline data characterising the transmission of early SARS-CoV-2 strains from children and adults in Australia, against which properties of variants of concern can be benchmarked. We encountered many challenges with respect to logistics, ethics, governance and data management. Continued efforts to invest in preparedness research will help to test, refine and further develop Australian FFX study protocols in advance of future outbreaks.
Australian Government Department of Health.
First few ‘X’ (FFX) studies for COVID-19 involve data collection from confirmed cases and their close contacts. They remain relevant especially as many remain susceptible to infection, and as they ...can provide detailed insight into vaccine effectiveness and the epidemiology of variants of concern, helping to inform a proportionate health response.
Background
Household transmission investigations (HHTIs) contribute timely epidemiologic knowledge in response to emerging pathogens. HHTIs conducted in the context of the COVID‐19 pandemic in ...2020‐21 reported variable methodological approaches, producing epidemiological estimates that vary in meaning, precision and accuracy. Because specific tools to assist with the optimal design and critical appraisal of HHTIs are not available, the aggregation and pooling of inferences from HHTIs to inform policy and interventions may be challenging.
Methods
In this manuscript, we discuss key aspects of the HHTI design, provide recommendations for the reporting of these studies and propose an appraisal tool that contributes to the optimal design and critical appraisal of HHTIs.
Results
The appraisal tool consists of 12 questions that explore 10 aspects of HHTIs and can be answered ‘yes’, ‘no’ or ‘unclear’. We provide an example of the use of this tool in the context of a systematic review that aimed to quantify the household secondary attack rate from HHTIs.
Conclusion
We seek to fill a gap in the epidemiologic literature and contribute to standardised HHTI approaches across settings to achieve richer and more informative datasets.
Background
Household studies are crucial for understanding the transmission of SARS‐CoV‐2 infection, which may be underestimated from PCR testing of respiratory samples alone. We aim to combine the ...assessment of household mitigation measures; nasopharyngeal, saliva, and stool PCR testing; along with mucosal and systemic SARS‐CoV‐2–specific antibodies, to comprehensively characterize SARS‐CoV‐2 infection and transmission in households.
Methods
Between March and September 2020, we obtained samples from 92 participants in 26 households in Melbourne, Australia, in a 4‐week period following the onset of infection with ancestral SARS‐CoV‐2 variants.
Results
The secondary attack rate was 36% (24/66) when using nasopharyngeal swab (NPS) PCR positivity alone. However, when respiratory and nonrespiratory samples were combined with antibody responses in blood and saliva, the secondary attack rate was 76% (50/66). SARS‐CoV‐2 viral load of the index case and household isolation measures were key factors that determine secondary transmission. In 27% (7/26) of households, all family members tested positive by NPS for SARS‐CoV‐2 and were characterized by lower respiratory Ct values than low transmission families (Median 22.62 vs. 32.91; IQR 17.06–28.67 vs. 30.37–34.24). High transmission families were associated with enhanced plasma antibody responses to multiple SARS‐CoV‐2 antigens and the presence of neutralizing antibodies. Three distinguishing saliva SARS‐CoV‐2 antibody features were identified according to age (IgA1 to Spike 1, IgA1 to nucleocapsid protein (NP)), suggesting that adults and children generate distinct mucosal antibody responses during the acute phase of infection.
Conclusion
Utilizing respiratory and nonrespiratory PCR testing, along with the measurement of SARS‐CoV‐2–specific local and systemic antibodies, provides a more accurate assessment of infection within households and highlights some of the immunological differences in response between children and adults.
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