In May 2023, the Shelby County Health Department identified a legionellosis outbreak among attendees of the same church. Epidemiologic, environmental, and laboratory investigations were initiated. Laboratory-based surveillance identified persons with a positive Legionella test result. Church attendees were surveyed about attendance, symptoms of legionellosis, and water exposures. Environmental assessment of the church included asking about recent water management practices and collecting samples from water sources for culture. The health department identified 16 church attendees who had legionellosis symptoms. Of these, 9 (56%) had positive laboratory test results for Legionella pneumophila, 7 were hospitalized, and none died. Our investigation revealed that recent changes in water management practices at the church included renewed operation of a large, jetted baptismal font. In all, 17 environmental samples were collected; of these samples, 5 (including 4 from the baptismal font) had L. pneumophila serogroup 1 isolated by culture. Environmental sampling was crucial in identifying the baptismal font as the likely source of L. pneumophila. Education about water management and remediation recommendations were provided to staff at the church.

Abstract Background National guidelines recommend testing infants perinatally exposed to hepatitis C virus (HCV). We sought to examine sociodemographic factors associated with HCV testing and infection among Tennessee infants. Comparison of Testing Practices for Infants Perinatally Exposed to HCV by Sociodemographic Characteristics — Tennessee, January 2018–July 2020 1 Percentages might not add up to 100% because of missing data. 2 This analysis excludes 177 infants with HCV testing that did not adhere with guidelines. Methods The Tennessee Department of Health conducts active perinatal HCV surveillance by requesting that clinicians report all HCV test results for perinatally exposed infants. For infants born during January 2018–July 2020, we linked birth certificate sociodemographic information with HCV test results as of July 31, 2023. We defined HCV RNA testing at 2–36 months or antibody testing at 18–36 months of age as guideline-adherent; testing conducted outside these ages as not guideline adherent. In Tennessee, perinatal hepatitis C is considered confirmed if positive RNA testing at 2–36 months, probable if positive antibody testing only at 18–36 months, and excluded if negative RNA testing at 2–36 months or negative antibody testing at ≤ 36 months of age. We calculated odds ratios (OR) to identify sociodemographic factors associated with guideline-adherent testing. Results Among 3,020 infants perinatally exposed to hepatitis C, 776 (26%) had guideline-adherent HCV testing, 177 (6%) had testing that was not guideline adherent, and 2,067 (68%) did not have any testing reported. Infants born to Black or Hispanic persons had lower odds of guideline-adherent testing, compared with White (OR = 0.33 [95% CI: 0.20–0.53]) or non-Hispanic (OR = 0.27 [95% CI: 0.11–0.68]) persons. Infants had higher odds of guideline-adherent testing if born to a person residing in a medium or small, compared with large metropolitan areas (OR = 2.94 [95% CI: 2.32-3.72]), or if public insurance was used at birth, compared with private insurance (OR = 1.64 [95% CI: 1.23–2.18]) (Table). Of 798 infants with hepatitis C status determined by 36 months of age, 51 (6.4%) had either confirmed (n = 45) or probable (n = 6) hepatitis C. Conclusion Most perinatally exposed infants in Tennessee were not tested for hepatitis C. Black and Hispanic infants were less often tested and residents of medium or small areas more often tested. Equitable implementation of testing practices for perinatally exposed infants is necessary to avoid compounding disparities in hepatitis C treatment. Disclosures All Authors: No reported disclosures

AIMS:In October 2023, the Tennessee Department of Health identified an outbreak of Shiga toxin-producing Escherichia coli (STEC) O157:H7 infections among elementary school students who attended school field trips to the same farm animal exhibit. Our aim was to determine STEC source and prevent additional illnesses by initiating epidemiologic, laboratory and environmental investigations. METHODS AND RESULTS:We identified cases using laboratory-based surveillance and by surveying caregivers of children who attended the exhibit. Probable cases were defined as illness with abdominal cramps or diarrhoea after attendance; confirmed cases were laboratory-confirmed STEC infection in an attendee or household contact. A site visit was conducted, and event organizers were interviewed. Human stool, animal faeces and environmental samples were tested for STEC O157:H7 by real-time polymerase chain reaction (PCR), culture and whole-genome sequencing (WGS). Approximately 2300 elementary school students attended the animal exhibit during 2 days. Field trip activities included contact with different farm animal species, drinking pasteurized milk outside animal enclosures and eating lunch in a separate building onsite. We received survey responses from 399 caregivers for 443 (19%) animal exhibit attendees. We identified 9 confirmed and 55 probable cases with illness onset dates during 26 September to 12 October. Seven children aged 1-7 years were hospitalized. Four children aged 1-6 years experienced haemolytic uraemic syndrome; none died. Laboratory testing identified STEC O157:H7 by culture from eight human stool samples with 0-1 allele difference by WGS. Three environmental samples had Shiga toxin (stx 2) genes detected by PCR, but no STEC isolates were recovered by culture. CONCLUSIONS:This is the largest reported STEC O157:H7 outbreak associated with an animal exhibit in Tennessee. We identified opportunities for educating school staff, event organizers and families about zoonotic disease risks associated with animal contact and published prevention measures.

Objectives:Mpox surveillance was integral during the 2022 outbreak response. We evaluated implementation of mpox surveillance in Tennessee during an outbreak response and made recommendations for surveillance during emerging infectious disease outbreaks. Methods: To understand surveillance implementation, system processes, and areas for improvement, we conducted 8 semistructured focus groups and 7 interviews with 36 health care, laboratory, and health department representatives during September 9-20, 2022. We categorized and analyzed session transcription and notes. We analyzed completeness and timeliness of surveillance data, including 349 orthopoxvirus-positive laboratory reports from commercial, public health, and health system laboratories during July 1-August 31, 2022. Results: Participants described an evolving system and noted that existing informatics platforms inefficiently supported iterations of reporting requirements. Clear communication, standardization of terminology, and shared, adaptable, and user-friendly informatics platforms were prioritized for future emerging infectious disease surveillance systems. Laboratory-reported epidemiologic information was often incomplete; only 55% (191 of 349) of reports included patient address and telephone number. The median time from symptom onset to specimen collection was 5 days (IQR, 3-6 d), from specimen collection to laboratory reporting was 3 days (IQR, 1-4 d), from laboratory reporting to patient interview was 1 day (IQR, 1-3 d), and from symptom onset to patient interview was 9 days (IQR, 7-12 d). Conclusions: Future emerging infectious disease responses would benefit from standardized surveillance approaches that facilitate rapid implementation. Closer collaboration among informatics, laboratory, and clinical partners across jurisdictions and agencies in determining system priorities and designing workflow processes could improve flexibility of the surveillance platform and completeness and timeliness of laboratory reporting. Improved timeliness will facilitate public health response and intervention, thereby mitigating morbidity.

Abstract Background In January 2023, the Tennessee Department of Health (TDH) received report of a positive measles result from a multiplex polymerase chain reaction (PCR) panel ordered to evaluate a fever and rash in a child. Immediate public health investigation concluded that the positive test was because of recent measles vaccination. Because multiplex PCR tests have not typically included measles, we assessed patient characteristics, provider responses, and measles virus strain when multiplex PCR identified measles to guide public health response in Tennessee. Methods We retrospectively identified Tennessee residents who tested positive for measles by 2 multiplex PCR panels, commercially available since 2022, that include 7–9 viruses and Streptococcus pyogenes. We queried the state immunization registry for measles vaccine records for those persons and asked ordering providers about their clinical assessment, test use, and response to the positive result. CDC performed the Measles Vaccine (MeVA) assay (real-time RT-PCR) on available clinical specimens. Results Of 296 multiplex PCR tests on Tennessee residents, 7 (2.4%) were positive for measles. Median age was 1 year (range: 1–6 years). All 7 received a measles vaccine within 8–15 days before the test. Among 7 providers, 6 did not suspect measles prior to testing. All ordered testing to evaluate a rash, with or without fever, and none were aware of patient exposure to persons with measles. After the positive result, 2 providers contacted TDH for guidance, 4 attributed the result to recent vaccination, and 1 reported not having received the test result. Three patients tested positive for additional viruses in the panel including enteroviruses (n = 2), human herpesvirus type 6 (n = 2), human herpesvirus type 7 (n = 1), and Epstein-Barr virus (n = 1). MeVA testing of 2 specimens identified measles vaccine strain in 1 specimen and an inconclusive result in the other. Conclusion Inclusion of measles in multiplex PCR panels can incidentally identify measles virus in recently vaccinated persons, requiring MeVA testing to confirm vaccine strain. In recently vaccinated persons, medical and public health professionals must carefully consider use and interpretation of measles results in multiplex PCR panels. Disclosures All Authors: No reported disclosures

Influenza seasons typically begin in October and peak between December and February (1); however, the 2022-23 influenza season in Tennessee began in late September and was characterized by high pediatric hospitalization rates during November. This report describes a field investigation conducted in Tennessee during November 2022, following reports of increasing influenza hospitalizations. Data from surveillance networks, patient surveys, and whole genome sequencing of influenza virus specimens were analyzed to assess influenza activity and secondary illness risk. Influenza activity increased earlier than usual among all age groups, and rates of influenza-associated hospitalization among children were high in November, reaching 12.6 per 100,000 in children aged <5 years, comparable to peak levels typically seen in high-severity seasons. Circulating influenza viruses were genetically similar to vaccine components. Among persons who received testing for influenza at outpatient clinics, children were twice as likely to receive a positive influenza test result as were adults. Among household contacts exposed to someone with influenza, children were more than twice as likely to become ill compared with adults. As the influenza season continues, it is important for all persons, especially those at higher risk for severe disease, to protect themselves from influenza. To prevent influenza and severe influenza complications, all persons aged ≥6 months should get vaccinated, avoid contact with ill persons, and take influenza antivirals if recommended and prescribed.

Context: It is well established that rural communities face geographic and socioeconomic challenges linked to higher rates of health disparities across the United States, though the coronavirus disease 2019 (COVID-19) impact on rural communities is less certain. Objective: To understand the COVID-19 pandemic's impact on rural communities in Tennessee, investigate differences in rural-urban mortality rates after controlling for confounding variables, and inform state pandemic response policy. Design: A cross-sectional analysis of cumulative COVID-19 morality rates. Setting/Participants: Tennessee county-level COVID-19 mortality data from March 1, 2020, to January 31, 2021, were matched with county-level sociodemographic and health data from public datasets: Agency for Healthcare Research and Quality Social Determinants of Health, PLACES: Local Data for Better Health County Data, and the US Census Bureau. County status was defined using the 2013 National Center for Health Statistics Urban-Rural Classification. Main Outcome Measures: A negative binomial regression model estimated adjusted incidence rate ratio and 95% confidence intervals (CI) for rural compared with urban mortality. Unadjusted rate ratios and rate differences for COVID-19 mortality in rural versus urban counties were compared with those for influenza and pneumonia and all-cause mortality over the past 5 years. Results: During the study period, 9650 COVID-19 deaths occurred across 42 urban and 53 rural counties. Controlling for county-level sociodemographic characteristics, health care access, and comorbidities, incidence rate ratio was 1.13 (95% CI, 1.00-1.28, P < .05) for rural as compared with urban deaths. Unadjusted COVID-19 mortality risk difference between rural and urban counties was greater (61.85, 95% CI, 54.31-69.31) than 5-year influenza and pneumonia rural-urban risk difference (12.57, 95% CI, 11.16-13.00) during 2015-2019. Conclusions: COVID-19 mortality rates were greater for populations living in Tennessee's rural as compared with urban counties during the study period. This differential impact must be considered in public health decision making to mitigate COVID-19.

On August 16, 2021, the Tennessee Department of Health (TDH) was notified of a positive rabies test result from a South American collared anteater (Tamandua tetradactyla) in Washington County, Tennessee. Tamanduas, or lesser anteaters, are a species of anteater in which rabies has not previously been reported. The animal was living at a Tennessee zoo and had been recently translocated from a zoo in Virginia. TDH conducted an investigation to confirm the rabies result, characterize the rabies variant, and ascertain an exposure risk assessment among persons who came into contact with the tamandua. Risk assessments for 22 persons were completed to determine the need for rabies postexposure prophylaxis (rPEP); rPEP was recommended for 13 persons, all of whom agreed to receive it. Using phylogenetic results of the virus isolated from the tamandua and knowledge of rabies epidemiology, public health officials determined that the animal was likely exposed to wild raccoons present at the Virginia zoo. This report describes expansion of the wide mammalian species diversity susceptible to rabies virus infection and summarizes the investigation, highlighting coordination among veterinary and human public health partners and the importance of preexposure rabies vaccination for animal handlers and exotic zoo animals.

Abstract Background Human-to-feline and airborne transmission among cats of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has been described, though documented feline-to-human transmission has not been reported. In October 2020, all 3 Malayan tigers at a Tennessee AZA accredited zoo were diagnosed with symptomatic SARS-CoV-2 infection. We investigated to determine source and prevent further transmission. Methods Tiger nasal swab specimens were tested at the National Veterinary Services Laboratories (NVSL). An environmental assessment at the zoo was completed. We interviewed 18 staff who interacted with the tigers during the 2 weeks before animal symptom onset. Confirmed human cases were defined as persons testing positive for SARS-CoV-2 by RT-PCR during September 28–October 29, with tiger interaction during their 14-day incubation period. Interviewed staff had repeat SARS-CoV-2 RT-PCR and serum IgG testing on October 29. Tigers and staff testing positive had specimens sent to CDC for genomic sequencing. Tiger sequences were compared phylogenetically with 30 geographically associated human cases collected within 2 weeks of the outbreak and > 200 background sequences from TN. Results NVSL confirmed SARS-CoV-2 infection in all 3 tigers. Environmental assessment identified fencing between humans and animals allowing airflow and an open outdoor exhibit observation point above the habitat. Confirmed cases were identified in a tiger keeper and veterinary assistant; both developed symptoms after exposure to symptomatic tigers and one sample was genotyped. Staff did not report known contact with ill visitors. All staff were negative for SARS-CoV-2 IgG. The tigers and most temporally and geographically associated cases had genetic sequences in clade 20G and B.1.2. Tiger sequences were 3-6 single nucleotide polymorphisms different from the positive tiger keeper (Figure). Figure. Whole-genome phylogenetic analysis. Whole-genome phylogenetic analysis from a portion of clade 20G showing divergence estimates from SARS-CoV-2 Wuhan-Hu-1 reference genome with sequences from humans living in Tennessee and Malayan tigers sampled during the outbreak investigation in October 2020. Sequence analysis showed 3-6 single nucleotide polymorphisms (SNPs) differences between one human tiger keeper and all three tiger sequences. Differences are indicated by one-step edges (lines) between colored dots (individual SARS-CoV-2 sequenced infections). Numbers indicate unique sequences. Note not all analyzed sequences are shown in this figure. Conclusion Using a One Health approach, we concluded the index tiger was likely infected via transmission from an ill visitor at an exhibit observation point or unidentified asymptomatic staff. Infection spread to the other 2 tigers and tiger-to-human transmission to 2 staff is possible thereafter. The zoo was advised on infection control practices for humans and animals, and no additional cases were identified. Disclosures William Schaffner, MD, VBI Vaccines (Consultant)

BACKGROUND:In the general adult population, lymphopaenia is associated with an increased risk for hospitalisation with infection and infection-related death. The quality of evidence and strength of association between perioperative lymphopaenia across different surgical procedures and mortality/morbidity has not been examined by systematic review or meta-analysis. METHODS:We searched MEDLINE, Embase, Web of Science, Google Scholar, and Cochrane databases from their inception to June 29, 2020 for observational studies reporting lymphocyte count and in-hospital mortality rate in adults. We defined preoperative lymphopaenia as a lymphocyte count 1.0-1.5×109 L-1. Meta-analysis was performed using either fixed or random effects models. Quality was assessed using the Newcastle-Ottawa Scale. The I2 index was used to quantify heterogeneity. The primary outcome was in-hospital mortality rate and mortality rate at 30 days. RESULTS:Eight studies met the inclusion criteria for meta-analysis, comprising 4811 patients (age range, 46-91 yr; female, 20-79%). These studies examined preoperative lymphocyte count exclusively. Studies were of moderate to high quality overall, ranking >7 using the Newcastle-Ottawa Scale. Preoperative lymphopaenia was associated with a threefold increase in mortality rate (risk ratio [RR]=3.22; 95% confidence interval [CI], 2.19-4.72; P<0.01, I2=0%) and more frequent major postoperative complications (RR=1.33; 95% CI, 1.21-1.45; P<0.01, I2=6%), including cardiovascular morbidity (RR=1.77; 95% CI, 1.45-2.15; P<0.01, I2=0%), infections (RR=1.45; 95% CI, 1.19-1.76; P<0.01, I2=0%), and acute renal dysfunction (RR=2.66; 95% CI, 1.49-4.77; P<0.01, I2=1%). CONCLUSION:Preoperative lymphopaenia is associated with death and complications more frequently, independent of the type of surgery. PROSPERO REGISTRY NUMBER:CRD42020190702.

While the large majority of foodborne illnesses cannot be attributed to a specific source, the identification and investigation of foodborne disease outbreaks is important for many reasons. The most immediate priority in investigating outbreaks is intervening to prevent further infections. Thorough investigations can also provide information about the immediate and originating sources of food contamination, changing pathogen epidemiology, changes in food production and handling processes, and new pathogens or vehicles of contamination. Better understanding of how such factors contribute to outbreaks can lead to insights into sporadic foodborne diseases and inform efforts to prevent them in the future, at all stages of the "farm-to-fork" continuum.

Abstract Introduction Lymphopaenia is common after major surgery and associated with poor outcome. T-lymphocytes restrain damaging innate inflammation. Major surgery impairs T-lymphocyte metabolism in humans, which promotes lymphopaenia. Metformin is known to improve mitochondrial bioenergetics in models of inflammation. Firstly, we hypothesised that a mouse model of major surgery would demonstrate impaired T-lymphocyte metabolism and secondly, that metformin treatment in vivo would reverse the phenotype. Method Male C57Bl/6 mice aged between 8 and 12 weeks were housed in a specific pathogen free environment with free access to food and water. Animals were dosed with either vehicle (phosphate buffered saline, 20 ml/kg) or metformin (250 mg/kg) daily via intraperitoneal injection for four days prior to and after surgery. A partial hepatectomy was performed under isofluorane anaesthesia. Naive littermates were used as controls. All experiments were performed according to the Animals (Scientific Procedures) Act 1986. Splenic T-lymphocytes were isolated by negative selection using magnetic beads. Mitochondrial bioenergetics were measured using a Seahorse Extracellular Flux analyser. Parametric statistical analysis was performed and a p-value < 0.05 was chosen to represent significance. Result T-lymphocytes demonstrated reduced spare respiratory capacity (SRC, 285 vs 497 %, p=0.004) after surgery compared to naive controls. Metformin treatment in vivo reversed this observation and SRC was comparable to naive (437 vs 497 %, p=0.34). Metformin treatment in vitro increased spare respiratory capacity in T-lymphocytes from mice after surgery compared to naive (change from untreated, 187 vs 91 %, p=0.03). Conclusion Perioperative metformin treatment improved T-lymphocyte metabolism in a mouse model of major surgery. Take-home message Metformin is a potential treatment for the lymphocyte metabolic dysfunction observed after surgery.

Background. Injection drug use (IDU) is an established but uncommon risk factor for candidemia. Surveillance for candidemia is conducted in East Tennessee, an area heavily impacted by the opioid crisis and IDU. We evaluated IDU-associated candidemia to characterize the epidemiology and estimate the burden. Methods. We assessed the proportion of candidemia cases related to IDU during January 1, 2014-September 30, 2018, estimated candidemia incidence in the overall population and among persons who inject drugs (PWID), and reviewed medical records to compare clinical features and outcomes among IDU-associated and non-IDU candidemia cases. Results. The proportion of IDU-associated candidemia cases in East Tennessee increased from 6.1% in 2014 to 14.5% in 2018. Overall candidemia incidence in East Tennessee was 13.5/100 000, and incidence among PWID was 402-1895/100 000. Injection drug use-associated cases were younger (median age, 34.5 vs 60 years) and more frequently had endocarditis (39% vs 3%). All-cause 30-day mortality was 8% among IDU-associated cases versus 25% among non-IDU cases. Conclusions. A growing proportion of candidemia in East Tennessee is associated with IDU, posing an additional burden from the opioid crisis. The lower mortality among IDU-associated cases likely reflects in part the younger demographic; however, Candida endocarditis seen among approximately 40% underscores the seriousness of the infection and need for prevention.

A 41-year-old woman was admitted with progressive paraesthesia and weakness and was diagnosed with Guillain-Barré syndrome. Following an initial period of recovery with intravenous immunoglobulin treatment, she developed acute chest pain associated with electrocardiographic changes. Investigations excluded acute coronary syndrome and instead confirmed a diagnosis of takotsubo cardiomyopathy, which was treated medically. The patient made an excellent neurological and cardiac recovery. Here we discuss the rarely described association between these two conditions and suggest that patients admitted with Guillain-Barré syndrome may benefit from routine screening with echocardiography.

Chronic inflammatory disorders, including rheumatoid arthritis (RA), are associated with a twofold increase in the incidence of sudden cardiac death (SCD) compared with the healthy population. Although this is partly explained by an increased prevalence of coronary artery disease, growing evidence suggests that ischemia alone cannot completely account for the increased risk. The present review explores the mechanisms of cardiac electrophysiological remodeling in response to chronic inflammation in RA. In particular, it focuses on the roles of nonischemic structural remodeling, altered cardiac ionic currents, and autonomic nervous system dysfunction in ventricular arrhythmogenesis and SCD. It also explores whether common genetic elements predispose to both RA and SCD. Finally, it evaluates the potential dual effects of disease-modifying therapy in both diminishing and promoting the risk of ventricular arrhythmias and SCD.

AIMS The European Society of Cardiology recommends coronary computed tomography (CCT) for the assessment of low-risk patients with suspected stable angina. We aimed to assess in a real-life setting the relative clinical value of stress echocardiography (SE)- and CCT-guided management in this population. METHODS AND RESULTS Patients with stable chest pain and no prior history of coronary artery disease (CAD) who underwent CCT or SE as the initial investigative strategy were propensity-matched (990 patients each group-age: 59 ± 13.2 years, males: 47.9%) to account for baseline differences in cardiovascular risk factors. Inconclusive tests were 6% vs. 3% (P < 0.005) in CCT vs. SE. Severe (≥70% stenosis) on CCT and inducible ischaemia on SE detected obstructive CAD by invasive coronary angiography in 63% vs. 57% patients (P = 0.33). Over the follow-up period (median 717, interquartile range 93-1069 days) more patients underwent invasive coronary angiography (21.5% vs. 7.3%, P < 0.005), revascularization (7.3% vs. 3.5%, P < 0.005), further functional testing 33.4% vs. 8.7% (P < 0.005), but more patients were prescribed statins 8.8% vs. 3.8% (P < 0.005) in the CCT vs. the SE arm, respectively. Combined all-cause mortality and acute myocardial infarction was low-CCT-2.3% and SE-3.3%-with no significant difference (P = 0.16). CONCLUSION Initial SE-guided management was similar for the detection of obstructive CAD, demonstrated better resource utilization, but was associated with reduced prescription of statins although with no difference in medium-term outcome compared to CCT in this very low-risk population. However, a randomized study with longer follow-up is needed to confirm the clinical value of our findings.

OBJECTIVE:The Tennessee Department of Health (TDH) investigated a hepatitis A virus (HAV) outbreak to identify risk factors for infection and make prevention recommendations.DESIGN:Case series.SETTING:Community hospital.PARTICIPANTS:Healthcare workers (HCWs) or patients with laboratory-confirmed acute HAV infection during October 1, 2018-January 10, 2019.METHODS:HCWs with suspected or confirmed hepatitis A infections were interviewed to assess their exposures and activities. Patient medical records and hospital administrative records were reviewed to identify common exposures. We conducted a site investigation to assess knowledge of infection control practices among HCWs. Serum specimens from ill persons were tested for HAV RNA by polymerase chain reaction (PCR) and genotyped.RESULTS:We identified 6 HCWs and 2 patients with laboratory-confirmed HAV infection. All cases likely resulted from exposure to a homeless patient with a history of recreational substance use and undiagnosed HAV infection. Breaches in hand hygiene and use of standard precautions were identified. HAV RNA was detected in 7 serum specimens and all belonged to an identical strain of HAV genotype 1b.CONCLUSIONS:A hepatitis A outbreak among hospital patients and HCWs resulted from exposure to a single patient with undiagnosed HAV infection. Breakdowns in infection control practices contributed to the outbreak. The likelihood of nosocomial transmission can be reduced with proper hand hygiene, standard precautions, and routine disinfection. During community outbreaks, medical providers can better prevent ongoing transmission by including hepatitis A in the differential diagnosis among patients with a history of recreational substance use and homelessness.

Objectives: Between 2003 and 2013, the rate of neonatal abstinence syndrome (NAS)—a postnatal drug withdrawal syndrome—in Tennessee increased approximately 10-fold. NAS surveillance is relatively new, and underestimation associated with surveillance has not been described. We compared data from the Tennessee NAS public health surveillance system (TNSS) with a second source of NAS data, hospital discharge data system (HDDS), and estimated the true number of infants with NAS using capture-recapture methods. Methods: We obtained NAS data on cases of NAS among Tennessee infants from TNSS and HDDS from January 1, 2013, through December 31, 2016. We matched cases of NAS identified in TNSS to cases identified in HDDS. We estimated the true number of infants with NAS by using the Lincoln-Peterson estimator capture-recapture methodology. Results: During the study period, 4070 infants with NAS were reported to TNSS, and 5321 infants with NAS were identified in HDDS; 2757 were in both data sets. Using capture-recapture methods, the total estimated number of infants with NAS during the study period was 7855 (annual mean = 1972; estimated range = 1531-2427), which was 93% more than in TNSS and 48% more than in HDDS. Drugs used for the medication-assisted treatment of substance use disorder were the most commonly reported substances associated with NAS (n = 2389, 59%). Conclusions: TNSS underestimated the total burden of NAS based on the capture-recapture estimate. Case-based public health surveillance is important for monitoring the burden of and risk factors for NAS and helping guide public health interventions.