Public Health Investigation Research Articles

A diphtheria outbreak in Johor Bahru, Malaysia: Public health investigation and response.

Diphtheria is an acute infectious disease caused by Corynebacterium diphtheriae. Although the incidence of diphtheria worldwide has rapidly declined following the largely successful diphtheria toxoid-based vaccines, concerns persist for those who were unvaccinated or incompletely vaccinated. In this report, we describe a recent diphtheria outbreak in Malaysia involving four confirmed diphtheria cases. The outbreak investigation efforts and epidemiological characteristics of a diphtheria outbreak in Malaysia are described. For all suspected cases, swabs were taken and sent for isolation of Corynebacterium diphtheriae and confirmation of toxigenic strains. The index case was a two-year-old child living with his family in a welfare home. Following contact tracing efforts and investigation for suspected cases, seven samples came back as culture positive for Corynebacterium diphtheriae. Confirmation of toxigenic strains was performed using PCR and Elek's test, which showed 100% correlation in positivity for four of the samples. All four confirmed cases were below 18 years of age, and three of them did not have complete vaccination history (two unvaccinated, one unknown). The index case eventually succumbed due to severe diphtheria with multiorgan failure while all the other cases were discharged healthy. In Malaysia, despite good vaccination coverage, sporadic diphtheria outbreaks still occur. The rising trend of cases reported over the recent years underscores the need to remain vigilant. Addressing pockets of unvaccinated children and potential waning immunity levels in the population remains pivotal.

Body Lice among People Experiencing Homelessness and Access to Hygiene Services during the COVID-19 Pandemic-Preventing Trench Fever in Denver, Colorado, 2020.

ABSTRACT.Eight people with human body louse-borne Bartonella quintana infections were detected among people experiencing homelessness (PEH) in Denver during January–September 2020, prompting a public health investigation and community outreach. Public health officials conducted in-person interviews with PEH to more fully quantify body lice prevalence, transmission risk factors, access to PEH resources, and how the COVID-19 pandemic has affected resource access. Recent body lice exposure was reported by 35% of 153 interview participants. In total, 75% of participants reported reduced access to PEH services, including essential hygiene activities to prevent body lice, during Colorado’s COVID-19 stay-at-home orders. Future pandemic planning should consider hygiene resource allocation for PEH populations to prevent emerging and reemerging infections such as B. quintana.

Public health response following an iGAS outbreak in a residential aged care facility in Queensland.

During an 18-day period, beginning in April 2020, three residents with invasive group A streptococcal infections (iGAS) were reported at a single residential aged care facility (RACF) in Brisbane's northern geographical region. All three cases were hospitalised with severe illness; two of the cases died as a result of the illness. The Metro North Public Health Unit (PHU) led the public health investigation and response, targeting infection control measures and offering chemoprophylaxis to all 142 staff and 119 residents at the facility. The outbreak was declared over in June, after 30 days of no new cases. Isolates from all three cases were shown to have identical strain typing, emm89. The benefits and challenges of implementing mass chemoprophylaxis in this setting are discussed.

A review of the circumstances and health-seeking behaviours associated with bat exposures in high-income countries.

Human–bat interactions are now the source of the majority of locally acquired human lyssavirus infections in many high‐income countries without hematophagous or ‘vampire’ bat species. This study aims to identify the most common types and circumstances of bat exposures occurring among members of the general public in high‐income countries with no hematophagous bats, and to describe the health‐seeking behaviours associated with exposures in these settings. We conducted a scoping review of relevant academic and grey literature on bat exposures and confirmed bat lyssavirus infections among members of the general public in Australia, Canada, the United States and high‐income European countries from 1996 to 2019. Case studies and population‐based studies were included for analysis, and findings were extracted and synthesized by the literature type and geographic region. A total of 63 publications were identified, including: 47 case studies and 16 population‐based studies. Overall, most exposures in Australia and Europe were intentionally initiated by humans and involved attempts to handle, touch or help a bat. In North America, however, household exposures were more common and predominantly involved a bat being found in a room or area where a person had slept. Studies also showed that a proportion of bat exposures in high‐income countries go unreported in the absence of a public health investigation and are therefore unlikely to receive prompt treatment. The results of this review suggest that the most effective strategies for preventing bat exposures vary between regions and that health‐seeking behaviours following bat exposures could be improved in high‐income settings.

LmTraceMap: A Listeria monocytogenes fast-tracing platform for global surveillance.

Listeria monocytogenes can cause listeriosis, and people with hypoimmunity such as pregnant women, infants and fetuses are at high risk of invasive infection. Although the incidence of listeriosis is low, the fatality rate is high. Therefore, continual surveillance and rapid epidemiological investigation are crucial for addressing L. monocytogenes. Because of the popularity of next-generation sequencing, obtaining the whole-genome sequence of a bacterium is easy. Several genome-based typing methods are available, and core-genome multilocus sequence typing (cgMLST) is the most recognized methods. Using cgMLST typing to compare L. monocytogenes whole-genome sequences (WGS) with those obtained across distinct regions is beneficial. However, the concern is how to incorporate the powerful cgMLST method into investigations, such as by using source tracing. Herein, we present an easy-to-use web service called–LmTraceMap (http://lmtracemap.cgu.edu.tw/hua_map/test/upload.php; http://120.126.17.192/hua_map/test/upload.php) that can help public-health professionals rapidly trace closely related isolates worldwide and visually inspect them in search results on a world map with labeled epidemiological data. We expect the proposed service to improve the convenience of public health investigations.

The Next Pandemic

The Next Pandemic

COVID-19 GPH: tracking the contribution of genomics and precision health to the COVID-19 pandemic response

The scientific response to the COVID-19 pandemic has produced an abundance of publications, including peer-reviewed articles and preprints, across a wide array of disciplines, from microbiology to medicine and social sciences. Genomics and precision health (GPH) technologies have had a particularly prominent role in medical and public health investigations and response; however, these domains are not simply defined and it is difficult to search for relevant information using traditional strategies. To quantify and track the ongoing contributions of GPH to the COVID-19 response, the Office of Genomics and Precision Public Health at the Centers for Disease Control and Prevention created the COVID-19 Genomics and Precision Health database (COVID-19 GPH), an open access knowledge management system and publications database that is continuously updated through machine learning and manual curation. As of February 11, 2022, COVID-GPH contained 31,597 articles, mostly on pathogen and human genomics (72%). The database also includes articles describing applications of machine learning and artificial intelligence to the investigation and control of COVID-19 (28%). COVID-GPH represents about 10% (22983/221241) of the literature on COVID-19 on PubMed. This unique knowledge management database makes it easier to explore, describe, and track how the pandemic response is accelerating the applications of genomics and precision health technologies. COVID-19 GPH can be freely accessed via https://phgkb.cdc.gov/PHGKB/coVInfoStartPage.action.

Perceptions about Telemedicine among Populations with Chronic Diseases amid COVID-19: Data from a Cross-Sectional Survey.

Chronic diseases, including non-communicable diseases (NCDs), have arisen as a severe threat to health and socio-economic growth. Telemedicine can provide both the highest level of patient satisfaction and the lowest risk of infection during a pandemic. The factors associated with its usage and patient adherence are not visible in Bangladesh’s resource-constrained settings. Therefore, this study aimed to identify perceptions about telemedicine among populations with chronic diseases amid the COVID-19 pandemic. A closed-ended self-reported questionnaire was created, and the questionnaire was written, reviewed, and finalized by a public health investigator, a psychiatrist, and an epidemiologist. The data for this study were collected from individuals using simple random sampling and snowball sampling techniques. Ethics approval was granted, and written/verbal consent was taken before interviews. Most of the participants showed a positive attitude towards telemedicine. People aged 35–54 years old and a higher level of education were less frequently associated with willingness to receive telemedicine services for current chronic disease (WRTCCD) than their counterparts. People living in urban areas and lower-income participants were more strongly associated with WRTCCD. Additionally, people who did not lose their earnings due to the pandemic were less strongly associated with WRTCCD. However, the main strength of this research is that it is a broad exploration of patient interest in several general forms of telehealth. In Bangladesh, there are many opportunities for telemedicine to be integrated into the existing healthcare system, if appropriate training and education are provided for healthcare professionals.

COVID-19: impact on Public Health and hypothesis-driven investigations on genetic susceptibility and severity.

COVID-19 is a new complex multisystem disease caused by the novel coronavirus SARS-CoV-2. In slightly over 2 years, it infected nearly 500 million and killed 6 million human beings worldwide, causing an unprecedented coronavirus pandemic. Currently, the international scientific community is engaged in elucidating the molecular mechanisms of the pathophysiology of SARS-CoV-2 infection as a basis of scientific developments for the future control of COVID-19. Global exome and genome analysis efforts work to define the human genetics of protective immunity to SARS-CoV-2 infection. Here, we review the current knowledge regarding the SARS-CoV-2 infection, the implications of COVID-19 to Public Health and discuss genotype to phenotype association approaches that could be exploited through the selection of candidate genes to identify the genetic determinants of severe COVID-19.

Risk factors for death and illness in dogs imported into the United States, 2010-2018.

CDC estimates 1 million dogs are imported into the United States annually. With the movement of large numbers of animals into the United States the risk of disease importation, especially emerging diseases, and animal welfare issues are of concern. Dogs that arrive to the United States ill or dead are investigated by public health authorities to ensure dogs are not infected with diseases of concern (such as rabies). We identified factors associated with illness and death in imported dogs and estimated the initial investigation cost to public health authorities. Dog importation data from the CDC’s Quarantine Activity Reporting System were reviewed from 2010 to 2018. The date of entry, country of origin, port of entry, transportation method and breed were extracted to examine factors associated with illness and death in dogs during international travel. Costs for public health investigations were estimated from data collected by the Bureau of Labor Statistics and Office of Personal Management. Death or illness was more likely to occur in brachycephalic breeds (aOR = 3.88, 95%CI 2.74–5.51). Transportation of dogs via cargo (aOR = 2.41, 95%CI 1.57–3.70) or as checked baggage (aOR = 5.74, 95%CI 3.65–9.03) were also associated with death or illness. On average, 19 dog illnesses or deaths were reported annually from 2010 to 2018. The estimated annual cost to public health authorities to conduct initial public health assessments ranged from $2,071 to $104,648. Current regulations do not provide adequate resources or mechanisms to monitor the rates of morbidity and mortality of imported dogs. There are growing attempts to assess animal welfare and communicable disease importation risks. However, because the responsibility for dogs’ health and wellbeing is overseen by multiple agencies it is challenging to coordinate implementation and enforcement measures. A joint federal agency approach to identify interventions that reduce dog morbidity and mortality during flights while continuing to protect US borders from public health and foreign animal disease threats could be beneficial.

Exploration of the fipronil in egg contamination incident in the Netherlands using the Functional Resonance Analysis Method

Following the 2017 fipronil egg contamination incident in the European Union, improvements in safety management continue to be necessary, particularly for regulatory, preventive, and control activities. Drawing from the Dutch and European legislation, and the use of the Functional Resonance Analysis Method (FRAM), the aim of the study was to explore the regulatory framing of the elimination of red mites on poultry farms, the compliance of actual events in 2017 with these hygiene standards and regulations in order to reconcile actual practices with policy directives. The study considers the difference between policy implementation for work-as-imagined and the tasks undertaken in practice i.e., ‘work-as-done’. This allows for assessment and analysis of the gap between pre-defined hygiene policy and actual practice and allows for a systemic approach rather than a causal approach to examine the public health incident. The study concludes that it is important for high level policy makers to comprehend the challenges and barriers faced by those implementing policy, and how this could potentially mean that policy in practice is not aligned with what was originally intended. The presented analysis outlines the potential of the FRAM in assessing complex food systems to support a public health investigation of incidents, and to design practical and realistic food safety policies leading to higher levels of stakeholder compliance and improved safety management. • 2017 Fipronil in egg contamination incident in the Netherlands was explored. • Red mites were eliminated through practices that did not comply with regulations. • Performance variability in public hygiene policies was a key failure in work as done. • The use of FRAM was of value in assessing complex food systems.

Airborne Transmission of SARS-CoV-2 Delta Variant within Tightly Monitored Isolation Facility, New Zealand (Aotearoa).

In New Zealand, international arrivals are quarantined and undergo severe acute respiratory syndrome coronavirus 2 screening; those who test positive are transferred to a managed isolation facility (MIF). Solo traveler A and person E from a 5-person travel group (BCDEF) tested positive. After transfer to the MIF, person A and group BCDEF occupied rooms >2 meters apart across a corridor. Persons B, C, and D subsequently tested positive; viral sequences matched A and were distinct from E. The MIF was the only shared location of persons A and B, C, and D, and they had no direct contact. Security camera footage revealed 4 brief episodes of simultaneous door opening during person A’s infectious period. This public health investigation demonstrates transmission from A to B, C, and D while in the MIF, with airborne transmission the most plausible explanation. These findings are of global importance for coronavirus disease public health interventions and infection control practices.

Congenital syphilis re-emergence in Winnipeg, Manitoba.

Infectious syphilis rates have been increasing in Winnipeg, Manitoba among individuals during their childbearing years. Untreated or inadequately treated prenatal infection often results in congenital syphilis, with devastating consequences to fetal health and survival. The objective of this study was to review public health surveillance data regarding congenital syphilis incidence and birthing parent risk factors in Winnipeg from 2018 to 2020. Data extracted from a population-based surveillance database maintained by the Winnipeg Regional Health Authority Public Health investigations for all 2018-2020 probable or confirmed cases of early congenital syphilis or syphilitic stillbirth were reviewed. Rates of congenital syphilis were calculated per 1,000 live births. Descriptive analyses were performed to describe birthing parent age, neighbourhood of residence, intravenous substance use, Child and Family Services involvement, access to prenatal care and obtainment of adequate prenatal treatment. There were eight cases of confirmed/probable congenital syphilis in 2018, 22 cases in 2019 and 30 cases in 2020. Average birthing parent age was 26.5-27.0 years. The majority (66.7%) of birthing parents lived in inner city neighbourhoods with known infectious syphilis outbreaks. Over 50% of birthing parents did not receive any prenatal care, or the care received consisted of inadequate treatment or follow-up. Reinfection among birthing parents who did receive prenatal care was suspected in an additional 23.3% of cases. Congenital syphilis rates in Winnipeg have increased dramatically. Public health and healthcare provider efforts to address the needs of the community are vital for promoting access to safe and effective prenatal care.

Permanent signatures of birth and nursing initiation are chemically recorded in teeth

In 2013 we presented a model for identifying nursing behavior from primate teeth based on rapid postnatal concentration changes in the non-essential trace element barium. Here we leverage the permanent neonatal (birth) line in the enamel of several dozen primate M1 cusps to compare pre- and postnatal trends in barium, zinc, strontium, and oxygen, as each element is believed to evince developmental patterning. Barium and zinc are the most consistent biomarkers of nursing initiation; a majority of M1 cusps shows concentration increases from prenatal to postnatal enamel, whereas strontium shows decreases or no change with similar frequency. Exceptions to the pattern of barium increase occurred in cusps that had been mineralizing for less than three weeks, suggesting that subsequent enamel maturation has only a minor impact on detecting real time events. Oxygen isotope compositions (δ18O) show rapid and marked fluctuations (∼1–2‰) within two weeks of birth in 93% of M1 cusps (n = 27/29). This is likely due to measurements of hypomineralized perinatal enamel and physiological changes in the body water of newborn infants. Ongoing work integrating elemental concentration gradients with isotopic variation will help establish the degree to which milk intake may cause elevated δ18O in teeth. We show that chemical identification of pre-to postnatal transitions may be robust to slight planar deviations that commonly obscure growth increments under light microscopy, and could help validate the identification of potential neonatal lines, making this approach a useful complement to bioarchaeological studies and public health investigations.

Involving People With Mental Illness in Research Important to Addressing Social Determinants of Health

Back to table of contents Previous article Next article Clinical & ResearchFull AccessInvolving People With Mental Illness in Research Important to Addressing Social Determinants of HealthPatrick Corrigan, Psy.D.Patrick CorriganSearch for more papers by this author, Psy.D.Published Online:28 Jan 2022https://doi.org/10.1176/appi.pn.2022.2.32AbstractPeople with serious mental illness have shown they can be vital members of a community-based participatory research team.iStock/AramyanPeople with serious mental illness die 10 to 20 years earlier than people of the same age—largely because of social determinants of health and mental health that undermine health and wellness.For many people with serious mental illness, common social determinants are poverty, lack of access to quality health and mental health care, stigma surrounding mental illness and its treatment, discrimination, high rates of smoking and alcohol and drug use, and poor diet and exercise patterns. People of color have an especially hard time accessing care—and care that is culturally sensitive.Interventions are beginning to emerge to overcome these barriers to health. They include medical practices that decrease the side effects of psychiatric treatments, psychoeducation to teach people how to manage health and wellness, instrumental and interpersonal supports that assist people to navigate their community, and shared decision-making that assures individuals have ultimate control over their health and wellness plan.Research is essential for the development and evaluation of strategies to address social determinants of health and mental health as a public health imperative at all levels of government. Community-based participatory research (CBPR) is the first principle: Research meant to test concepts and interventions specific to a community needs to be steeped in that community. This does not mean people are subjects of the research but rather partners in all facets of its conduct. Investigators and members of each community as partners define hypotheses, methods, analyses, and summaries of the research and development effort. CBPR is especially notable “coming into” and “going out of” a targeted research project. “Coming in,” members of the community have fundamental insights about what needs to be examined to make sense of their problems and ways to impact them; “going out” is ownership. Researchers on the CBPR team often go on to the next research project when data are analyzed and reports written up. Community members are likely to make use of the insights to meaningfully impact their neighborhood over time. The final plan is not something developed in the ivory tower by researchers who differ from the community, but by the community itself. This kind of ownership gives credibility.Who is community? They are people with shared experience relevant to health and wellness. Typically, CBPR focuses on diversity, especially in terms of ethnicity and religious heritage. Public health investigators also may seek to include additional communities of concern including women, LGBTQ individuals, veterans, and rural residents.People with serious mental illness are a community worthy of CBPR. They have shared experience and similar needs vis-à-vis the health care system. Some might ask whether people with serious mental illness can capably participate in CBPR given their social and cognitive disabilities. The answer is yes, they can be vital members of the CBPR team, especially when team members provide reasonable accommodations.This is meant to be a clarion call for psychiatrists and health care professionals of all kinds. Psychiatrists need to be mindful of the many ways they can help people with mental health challenges address their physical health needs, both within their own practice and in partnership with other health care professionals. ■Patrick Corrigan, Psy.D., is a distinguished professor of psychology at the Illinois Institute of Technology and the co-editor of Health and Wellness in People Living With Serious Mental Illness from APA Publishing. Members may purchase the book at a discount here. ISSUES NewArchived

Diagnostic and public health investigation of Mycobacterium tuberculosis infection in a dog in Ontario, Canada

A 4-y-old, female mixed-breed dog was presented to the Ontario Veterinary College for further evaluation of multiple pulmonary and hepatic masses, intrathoracic lymphadenitis, and recent development of a pyogranulomatous pleural effusion. Along with other comprehensive tests, a thoracic lymph node biopsy was performed, and Mycobacterium tuberculosis complex infection was confirmed by real-time PCR. The dog’s condition declined post-operatively, and euthanasia was elected. Postmortem examination confirmed severe granulomatous pneumonia, hepatitis, intrathoracic and intraabdominal lymphadenitis, omentitis, and nephritis. Line-probe assays performed on samples collected postmortem confirmed the species as M. tuberculosis. 24-loci MIRU-VNTR genotyping, spoligotyping, and whole-genome sequencing revealed relations to known human isolates, but no epidemiologic link to these cases was investigated. Given the concern for potential human exposure during this animal’s disease course, a public health investigation was initiated; 45 individuals were tested for M. tuberculosis exposure, and no subsequent human infections related to this animal were identified. Our case highlights the need for more readily available, minimally invasive testing for the diagnosis of canine mycobacteriosis, and highlights the ability of canid species to act as potential contributors to the epidemiology of M. tuberculosis infections.

Enhancing the effectiveness of contact tracing interviews: A randomized controlled experiment of an enhanced cognitive interview protocol

To compare the efficacy of a psychologically-based contact tracing interview protocol to a control protocol that emulated current practices under both interviewer-led and self-led modalities. This randomized controlled experiment utilized a 2×2 factorial design (Enhanced Cognitive protocol vs Control protocol; Interviewer-led call vs Self-led online survey). Data were collected online (n=200; Mage=44; 56.5% female; 79.5% White) during the COVID-19 pandemic (July 2, 2020 - September 15, 2020). The Enhanced Cognitive protocol increased reported close contacts by 51% compared with the Control protocol (d=0.44 [0.15, 0.71]). This effect was present for both interview modalities and for both identifiable and non-identifiable contacts. The Enhanced Cognitive protocol also increased both the quantity of person descriptors (d=1.36 [0.87, 1.85]) and the utility of descriptions (r=0.35 [0.13, 0.53]). The application of cognitive principles in contact tracing interviews can significantly enhance the quantity and quality of information provided by respondents. Epidemiologists and public health investigators could benefit from utilizing cognitive principles and self-led modalities in contact tracing interviews.

802. Corynebacterium striatum Outbreak Among Ventilated COVID-19 Patients in an Acute Care Hospital – California, 2021

Background Corynebacterium striatum (CS), a common human commensal colonizing the skin and nasopharynx, has been associated with nosocomial infections in immunocompromised and chronically ill patients. During the winter 2020-2021 COVID-19 surge, a 420-bed California hospital reported a marked increase in CS respiratory cultures among ventilated COVID-19 patients. We conducted a public health investigation to assess and mitigate nosocomial transmission and contributing infection prevention and control (IPC) practices. MethodsA case was defined as a patient with CS in respiratory cultures from January 1, 2020 - February 28, 2021. We reviewed clinical characteristics on a subset of cases in 2021 and IPC practices in affected hospital locations. CS respiratory isolates collected on different dates and locations were assessed for relatedness by whole genome sequencing (WGS) on MiSeq.ResultsEighty-three cases were identified, including 75 among COVID-19 patients (Figure 1). Among 62 patients identified in 2021, all were ventilated; 58 also had COVID-19, including 4 cases identified on point prevalence survey (PPS). The median time from admission to CS culture was 19 days (range, 0-60). Patients were critically ill; often it was unclear whether CS cultures represented colonization or infection. During the COVID-19 surge, two hospital wings (7W and 7S) were converted to negative-pressure COVID-19 units. Staff donned and doffed personal protective equipment in anterooms outside the units; extended use of gowns was practiced, and lapses in glove changes and hand hygiene (HH) between patients likely occurred. In response to the CS outbreak, patients were placed in Contact precautions and cohorted. Staff were re-educated on IPC for COVID-19 patients. Gowns were changed between CS patients. Subsequent PPS were negative. Two CS clusters were identified by WGS: cluster 1 (5 cases) in unit 7W, and cluster 2 (2 cases) in unit 7S (Figure 2). Figure 1. Corynebacterium striatum Respiratory Cultures January 2020-February 2021 Figure 2. Phylogenetic Tree Corynebacterium striatum Isolates ConclusionA surge in patients, extended use of gowns and lapses in core IPC practices including HH and environmental cleaning and disinfection during the winter 2020-2021 COVID-19 surge likely contributed to this CS outbreak. WGS provides supportive evidence for nosocomial CS transmission among critically ill COVID-19 patients. Disclosures All Authors: No reported disclosures

Human Melioidosis Caused by Novel Transmission of Burkholderia pseudomallei from Freshwater Home Aquarium, United States1.

Nearly all cases of melioidosis in the continental United States are related to international travel to areas to which Burkholderia pseudomallei, the bacterium that causes melioidosis, is endemic. We report the diagnosis and clinical course of melioidosis in a patient from the United States who had no international travel history and the public health investigation to determine the source of exposure. We tested environmental samples collected from the patient’s home for B. pseudomallei by PCR and culture. Whole-genome sequencing was conducted on PCR-positive environmental samples, and results were compared with sequences from the patient’s clinical specimen. Three PCR-positive environmental samples, all collected from a freshwater home aquarium that had contained imported tropical fish, were a genetic match to the clinical isolate from the patient. This finding suggests a novel route of exposure and a potential for importation of B. pseudomallei, a select agent, into the United States from disease-endemic areas.

The utility of SARS‐CoV‐2‐specific serology in COVID‐19 diagnosis

IntroductionIn May 2020, The Communicable Diseases Network of Australia (CDNA) case definition introduced serological criteria to support the diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). We present findings that support the utility of SARS‐CoV‐2‐specific serology for public health investigations. MethodsFrom 24 January to 31 July 2020, the following information was collected from individuals with positive SARS‐CoV‐2‐specific immunofluorescence antibody tests: history of contact with COVID‐19 cases; recent travel; symptoms consistent with COVID‐19; and SARS‐CoV‐2 nucleic acid testing (NAT) results. Individuals were classified as confirmed or probable by CDNA criteria or additionally as possible (SARS‐CoV‐2‐specific IgG positive with compatible symptoms or epidemiologic risk) or indeterminate (SARS‐CoV‐2‐specific IgA/IgM positive only) cases. ResultsA total of 10,595 individuals were tested in the six‐month period. Of these, 9.8% (1,037) individuals had positive SARS‐CoV‐2‐specific serology of which 566 (53.6%) were NAT‐confirmed COVID‐19 cases and 286 (27.6%) were part of a cruise ship outbreak sero‐survey. The remaining 185 individuals (NAT negative) were individually classified as serologically confirmed (4, 0.4%), probable (72, 6.9%) possible (66, 6.4%) and indeterminate (38, 3.7%) cases. Maternal antibody transfer was inferred in one infant and four were unclassified. ConclusionSARS‐CoV‐2‐specific serology is a key diagnostic tool for retrospective identification of COVID‐19 infection. Implications for public healthSARS‐CoV‐2 specific serology can enhance the ability to find cases, link missing cases in clusters of infection and identify the epidemiological extent of SARS‐CoV‐2 outbreaks. A combination of epidemiological criteria, clinical criteria and a quantitative serological test can be used as an adjunct to classify SARS‐CoV‐2 cases. Our study confirms the low level of community transmission in NSW during the first year of the COVID‐19 pandemic