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Zhu Y, Xia Y, Pickering J, Bowen AC, Short KR. The role of children in transmission of SARS-CoV-2 variants of concern within households: an updated systematic review and meta-analysis, as at 30 June 2022. Euro Surveill 2023; 28:2200624. [PMID: 37140450 PMCID: PMC10161681 DOI: 10.2807/1560-7917.es.2023.28.18.2200624] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 03/17/2023] [Indexed: 05/05/2023] Open
Abstract
BackgroundMeta-analyses and single-site studies have established that children are less infectious than adults within a household when positive for ancestral SARS-CoV-2. In addition, children appear less susceptible to infection when exposed to ancestral SARS-CoV-2 within a household. The emergence of SARS-CoV-2 variants of concern (VOC) has been associated with an increased number of paediatric infections worldwide. However, the role of children in the household transmission of VOC, relative to the ancestral virus, remains unclear.AimWe aimed to evaluate children's role in household transmission of SARS-CoV-2 VOC.MethodsWe perform a meta-analysis of the role of children in household transmission of both ancestral SARS-CoV-2 and SARS-CoV-2 VOC.ResultsUnlike with the ancestral virus, children infected with VOC spread SARS-CoV-2 to an equivalent number of household contacts as infected adults and were equally as likely to acquire SARS-CoV-2 VOC from an infected family member. Interestingly, the same was observed when unvaccinated children exposed to VOC were compared with unvaccinated adults exposed to VOC.ConclusionsThese data suggest that the emergence of VOC was associated with a fundamental shift in the epidemiology of SARS-CoV-2. It is unlikely that this is solely the result of age-dependent differences in vaccination during the VOC period and may instead reflect virus evolution over the course of the pandemic.
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Affiliation(s)
- Yanshan Zhu
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
- Wesfarmer's Centre for Vaccines and Infectious Diseases, Telethon Kids Institute, University of Western Australia, Nedlands, Perth, Australia
- These authors contributed equally to this manuscript
| | - Yao Xia
- Department of Microbiology, State Key Laboratory of Emerging Infectious Diseases, Carol Yu Centre for Infection, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China
- These authors contributed equally to this manuscript
| | - Janessa Pickering
- Wesfarmer's Centre for Vaccines and Infectious Diseases, Telethon Kids Institute, University of Western Australia, Nedlands, Perth, Australia
| | - Asha C Bowen
- Wesfarmer's Centre for Vaccines and Infectious Diseases, Telethon Kids Institute, University of Western Australia, Nedlands, Perth, Australia
- Department of Infectious Diseases, Perth Children's Hospital, Nedlands, Perth, Australia
| | - Kirsty R Short
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Australia
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Wang C, Huang X, Lau EHY, Cowling BJ, Tsang TK. Association Between Population-Level Factors and Household Secondary Attack Rate of SARS-CoV-2: A Systematic Review and Meta-analysis. Open Forum Infect Dis 2022; 10:ofac676. [PMID: 36655186 PMCID: PMC9835764 DOI: 10.1093/ofid/ofac676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Background Accurate estimation of household secondary attack rate (SAR) is crucial to understand the transmissibility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The impact of population-level factors, such as transmission intensity in the community, on SAR estimates is rarely explored. Methods In this study, we included articles with original data to compute the household SAR. To determine the impact of transmission intensity in the community on household SAR estimates, we explored the association between SAR estimates and the incidence rate of cases by country during the study period. Results We identified 163 studies to extract data on SARs from 326 031 cases and 2 009 859 household contacts. The correlation between the incidence rate of cases during the study period and SAR estimates was 0.37 (95% CI, 0.24-0.49). We found that doubling the incidence rate of cases during the study period was associated with a 1.2% (95% CI, 0.5%-1.8%) higher household SAR. Conclusions Our findings suggest that the incidence rate of cases during the study period is associated with higher SAR. Ignoring this factor may overestimate SARs, especially for regions with high incidences, which further impacts control policies and epidemiological characterization of emerging variants.
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Affiliation(s)
- Can Wang
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Xiaotong Huang
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Eric H Y Lau
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China,Laboratory of Data Discovery for Health Limited, Hong Kong Science and Technology Park, New Territories, Hong Kong Special Administrative Region, China
| | - Benjamin J Cowling
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China,Laboratory of Data Discovery for Health Limited, Hong Kong Science and Technology Park, New Territories, Hong Kong Special Administrative Region, China
| | - Tim K Tsang
- Correspondence: Tim K. Tsang, PhD, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 7 Sassoon Road, Pokfulam, Hong Kong Special Administrative Region, China ()
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Chen F, Tian Y, Zhang L, Shi Y. The role of children in household transmission of COVID-19: a systematic review and meta-analysis. Int J Infect Dis 2022; 122:266-275. [PMID: 35562045 PMCID: PMC9091150 DOI: 10.1016/j.ijid.2022.05.016] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/03/2022] [Accepted: 05/07/2022] [Indexed: 02/08/2023] Open
Abstract
OBJECTIVES To explore household transmissibility of SARS-CoV-2 in children in new-variants dominating periods. METHODS Through retrieval in PubMed and Embase, studies were included in two parts: meta-analysis of the household secondary attack rate (SAR) and case analysis of household pediatric infections. RESULTS A total of 95 articles were included: 48 for meta-analysis and 47 for case analysis. Pediatric COVID-19 only comprised a minority of the household transmission. The total pooled household SAR of child index cases and contacts were 0.20 (95% confidence interval [CI]: 0.15-0.26) and 0.24 (95% CI: 0.18-0.30). Lower household transmissibility was reported in both child index cases and contacts than in adults (relative risk [RR] = 0.64, 95% CI: 0.50-0.81; RR = 0.74, 95% CI: 0.64-0.85). Younger children were as susceptible as the older children (RR = 0.89, 95% CI: 0.72-1.10). Through subgroup analyses of different variants and periods, increased household SAR was observed in children (Wild: 0.20; Alpha: 0.42; Delta: 0.35; Omicron: 0.56), and no significant difference was found in household SAR between children and adults when new variants dominated. CONCLUSION Although children were found not to be dominant in the household transmission, their transmissibility of SARS-CoV-2 appeared to be on the rise as new variants emerged.
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Affiliation(s)
| | | | | | - Yuan Shi
- Corresponding author: Yuan Shi, Children's Hospital of Chongqing Medical University, Chongqing 400014, China, Mob: 00862363635678
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Sumner KM, Karron RA, Stockwell MS, Dawood FS, Stanford JB, Mellis A, Hacker E, Thind P, Castro MJE, Harris JP, Knoll MD, Schappell E, Hetrich MK, Duque J, Jeddy Z, Altunkaynak K, Poe B, Meece J, Stefanski E, Tong S, Lee JS, Dixon A, Veguilla V, Rolfes MA, Porucznik CA. Impact of age and symptom development on SARS-CoV-2 transmission in households with children—Maryland, New York, and Utah, August 2020–October 2021. Open Forum Infect Dis 2022; 9:ofac390. [PMID: 35991589 PMCID: PMC9384637 DOI: 10.1093/ofid/ofac390] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 08/05/2022] [Indexed: 11/13/2022] Open
Abstract
ABSTRACT
Background
Households are common places for spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We investigated factors associated with household transmission and acquisition of SARS-CoV-2.
Methods
Households with children ages <18 years were enrolled into prospective, longitudinal cohorts and followed August 2020─August 2021 in Utah, September 2020─August 2021 in New York City, and November 2020─October 2021 in Maryland. Participants self-collected nasal swabs weekly and with onset of acute illness. Swabs were tested for SARS-CoV-2 using reverse-transcription polymerase chain reaction. We assessed factors associated with SARS-CoV-2 acquisition using a multi-level logistic regression adjusted for household size and clustering and SARS-CoV-2 transmission using a logistic regression adjusted for household size.
Results
Among 2,053 people (513 households) enrolled, 180 people (8.8%; in 76 households) tested positive for SARS-CoV-2. Compared to children <12y, odds of acquiring infection were lower for adults ≥18y (adjusted odds ratio[aOR]:0.34, 95% confidence interval[CI]:0.14–0.87); however, this may reflect vaccination status, which protected against SARS-CoV-2 acquisition (aOR:0.17, 95%CI:0.03–0.91). Odds of onward transmission was similar between symptomatic and asymptomatic primary cases (aOR:1.00, 95%CI:0.35–2.93) and did not differ by age (12–17vs. < 12y aOR:1.08, 95%CI:0.20–5.62; ≥18vs. < 12y aOR:1.70, 95%CI:0.52–5.83).
Conclusions
Adults had lower odds of acquiring SARS-CoV-2 compared to children, but this association might be influenced by COVID-19 vaccination, which was primarily available for adults and protective against infection. In contrast, all ages, regardless of symptoms and COVID-19 vaccination, had similar odds of transmitting SARS-CoV-2. Findings underscore the importance of SARS-CoV-2 mitigation measures for persons of all ages.
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Affiliation(s)
- Kelsey M Sumner
- Centers for Disease Control and Prevention COVID-19 Response , Atlanta, GA , USA
- Epidemic Intelligence Service, Centers for Disease Control and Prevention , Atlanta, GA , USA
| | - Ruth A Karron
- Center for Immunization Research, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University , Baltimore, MD , USA
| | - Melissa S Stockwell
- Division of Child and Adolescent Health, Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center , New York, NY , USA
- Department of Population and Family Health, Mailman School of Public Health, Columbia University Irving Medical Center , New York, NY , USA
| | - Fatimah S Dawood
- Centers for Disease Control and Prevention COVID-19 Response , Atlanta, GA , USA
| | - Joseph B Stanford
- Division of Public Health, Department of Family and Preventive Medicine, University of Utah School of Medicine , Salt Lake City, UT , USA
| | - Alexandra Mellis
- Centers for Disease Control and Prevention COVID-19 Response , Atlanta, GA , USA
| | - Emily Hacker
- Division of Public Health, Department of Family and Preventive Medicine, University of Utah School of Medicine , Salt Lake City, UT , USA
| | - Priyam Thind
- Division of Child and Adolescent Health, Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center , New York, NY , USA
| | - Maria Julia E Castro
- Division of Child and Adolescent Health, Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center , New York, NY , USA
| | - John Paul Harris
- Division of Child and Adolescent Health, Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center , New York, NY , USA
| | - Maria Deloria Knoll
- International Vaccine Access Center, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University , Baltimore, MD , USA
| | - Elizabeth Schappell
- Center for Immunization Research, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University , Baltimore, MD , USA
| | - Marissa K Hetrich
- International Vaccine Access Center, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University , Baltimore, MD , USA
| | | | | | | | | | - Jennifer Meece
- Marshfield Clinic Research Institute , Marshfield, WI , USA
| | | | - Suxiang Tong
- Centers for Disease Control and Prevention COVID-19 Response , Atlanta, GA , USA
| | - Justin S Lee
- Centers for Disease Control and Prevention COVID-19 Response , Atlanta, GA , USA
| | - Ashton Dixon
- Centers for Disease Control and Prevention COVID-19 Response , Atlanta, GA , USA
| | - Vic Veguilla
- Centers for Disease Control and Prevention COVID-19 Response , Atlanta, GA , USA
| | - Melissa A Rolfes
- Centers for Disease Control and Prevention COVID-19 Response , Atlanta, GA , USA
| | - Christina A Porucznik
- Division of Public Health, Department of Family and Preventive Medicine, University of Utah School of Medicine , Salt Lake City, UT , USA
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Winkler ML, Hooper DC, Shenoy ES. Infection Prevention and Control of Severe Acute Respiratory Syndrome Coronavirus 2 in Health Care Settings. Infect Dis Clin North Am 2022; 36:309-326. [PMID: 35636902 PMCID: PMC8806155 DOI: 10.1016/j.idc.2022.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The authors describe infection prevention and control approaches to severe acute respiratory syndrome coronavirus 2 in the health care setting, including a review of the chain of transmission and the hierarchy of controls, which are cornerstones of infection control and prevention. The authors also discuss lessons learned from nosocomial transmission events.
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Affiliation(s)
- Marisa L. Winkler
- Infection Control Unit, Massachusetts General Hospital, 55 Fruit Street, Bulfinch 334, Boston, MA 02114, USA,Division of Infectious Diseases, Massachusetts General Hospital, 55 Fruit Street, Boston, MA, 02114, USA,Harvard Medical School, 25 Shattuck Street, Boston, MA, 02115, USA,Corresponding author. Massachusetts General Hospital, 55 Fruit Street, Bulfinch 334, Boston, MA, 02114
| | - David C. Hooper
- Infection Control Unit, Massachusetts General Hospital, 55 Fruit Street, Bulfinch 334, Boston, MA 02114, USA,Division of Infectious Diseases, Massachusetts General Hospital, 55 Fruit Street, Boston, MA, 02114, USA,Harvard Medical School, 25 Shattuck Street, Boston, MA, 02115, USA
| | - Erica S. Shenoy
- Infection Control Unit, Massachusetts General Hospital, 55 Fruit Street, Bulfinch 334, Boston, MA 02114, USA,Division of Infectious Diseases, Massachusetts General Hospital, 55 Fruit Street, Boston, MA, 02114, USA,Harvard Medical School, 25 Shattuck Street, Boston, MA, 02115, USA
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Madewell ZJ, Yang Y, Longini IM, Halloran ME, Dean NE. Household Secondary Attack Rates of SARS-CoV-2 by Variant and Vaccination Status: An Updated Systematic Review and Meta-analysis. JAMA Netw Open 2022; 5:e229317. [PMID: 35482308 PMCID: PMC9051991 DOI: 10.1001/jamanetworkopen.2022.9317] [Citation(s) in RCA: 105] [Impact Index Per Article: 52.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
IMPORTANCE An overall household secondary attack rate (SAR) of 18.9% (95% CI, 16.2%-22.0%) through June 17, 2021 was previously reported for SARS-CoV-2. Emerging variants of concern and increased vaccination have affected transmission rates. OBJECTIVE To evaluate how reported household SARs changed over time and whether SARs varied by viral variant and index case and contact vaccination status. DATA SOURCES PubMed and medRxiv from June 18, 2021, through March 8, 2022, and reference lists of eligible articles. Preprints were included. STUDY SELECTION Articles with original data reporting the number of infected and total number of household contacts. Search terms included SARS-CoV-2, COVID-19, variant, vaccination, secondary attack rate, secondary infection rate, household, index case, family contacts, close contacts, and family transmission. DATA EXTRACTION AND SYNTHESIS The Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guideline was followed. Meta-analyses used generalized linear mixed models to obtain SAR estimates and 95% CIs. MAIN OUTCOMES AND MEASURES SAR stratified by covariates according to variant, index case and contact vaccination status, and index case identification period. SARs were used to estimate vaccine effectiveness on the basis of the transmission probability for susceptibility to infection (VES,p), infectiousness given infection (VEI,p), and total vaccine effectiveness (VET,p). RESULTS Household SARs were higher for 33 studies with midpoints in 2021 to 2022 (37.3%; 95% CI, 32.7% to 42.1%) compared with 63 studies with midpoints through April 2020 (15.5%; 95% CI, 13.2% to 18.2%). Household SARs were 42.7% (95% CI, 35.4% to 50.4%) for Omicron (7 studies), 36.4% (95% CI, 33.4% to 39.5%) for Alpha (11 studies), 29.7% (95% CI, 23.0% to 37.3%) for Delta (16 studies), and 22.5% (95% CI, 18.6% to 26.8%) for Beta (3 studies). For full vaccination, VES,p was 78.6% (95% CI, 76.0% to 80.9%) for Alpha, 56.4% (95% CI, 54.6% to 58.1%) for Delta, and 18.1% (95% CI, -18.3% to 43.3%) for Omicron; VEI,p was 75.3% (95% CI, 69.9% to 79.8%) for Alpha, 21.9% (95% CI, 11.0% to 31.5%) for Delta, and 18.2% (95% CI, 0.6% to 32.6%) for Omicron; and VET,p was 94.7% (95% CI, 93.3% to 95.8%) for Alpha, 64.4% (95% CI, 58.0% to 69.8%) for Delta, and 35.8% (95% CI, 13.0% to 52.6%) for Omicron. CONCLUSIONS AND RELEVANCE These results suggest that emerging SARS-CoV-2 variants of concern have increased transmissibility. Full vaccination was associated with reductions in susceptibility and infectiousness, but more so for Alpha than Delta and Omicron. The changes in estimated vaccine effectiveness underscore the challenges of developing effective vaccines concomitant with viral evolution.
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Affiliation(s)
| | - Yang Yang
- Department of Biostatistics, University of Florida, Gainesville
| | - Ira M. Longini
- Department of Biostatistics, University of Florida, Gainesville
| | - M. Elizabeth Halloran
- Fred Hutchinson Cancer Research Center, Seattle, Washington
- Department of Biostatistics, University of Washington, Seattle
| | - Natalie E. Dean
- Department of Biostatistics and Bioinformatics, Emory University, Atlanta, Georgia
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Madewell ZJ, Yang Y, Longini IM, Halloran ME, Dean NE. Household secondary attack rates of SARS-CoV-2 by variant and vaccination status: an updated systematic review and meta-analysis. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2022:2022.01.09.22268984. [PMID: 35043125 PMCID: PMC8764734 DOI: 10.1101/2022.01.09.22268984] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
We previously reported a household secondary attack rate (SAR) for SARS-CoV-2 of 18.9% through June 17, 2021. To examine how emerging variants and increased vaccination have affected transmission rates, we searched PubMed from June 18, 2021, through January 7, 2022. Meta-analyses used generalized linear mixed models to obtain SAR estimates and 95%CI, disaggregated by several covariates. SARs were used to estimate vaccine effectiveness based on the transmission probability for susceptibility ( VE S,p ), infectiousness ( VE I,p ), and total vaccine effectiveness ( VE T,p ). Household SAR for 27 studies with midpoints in 2021 was 35.8% (95%CI, 30.6%-41.3%), compared to 15.7% (95%CI, 13.3%-18.4%) for 62 studies with midpoints through April 2020. Household SARs were 38.0% (95%CI, 36.0%-40.0%), 30.8% (95%CI, 23.5%-39.3%), and 22.5% (95%CI, 18.6%-26.8%) for Alpha, Delta, and Beta, respectively. VE I,p , VE S,p , and VE T,p were 56.6% (95%CI, 28.7%-73.6%), 70.3% (95%CI, 59.3%-78.4%), and 86.8% (95%CI, 76.7%-92.5%) for full vaccination, and 27.5% (95%CI, -6.4%-50.7%), 43.9% (95%CI, 21.8%-59.7%), and 59.9% (95%CI, 34.4%-75.5%) for partial vaccination, respectively. Household contacts exposed to Alpha or Delta are at increased risk of infection compared to the original wild-type strain. Vaccination reduced susceptibility to infection and transmission to others. SUMMARY Household secondary attack rates (SARs) were higher for Alpha and Delta variants than previous estimates. SARs were higher to unvaccinated contacts than to partially or fully vaccinated contacts and were higher from unvaccinated index cases than from fully vaccinated index cases.
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Affiliation(s)
| | - Yang Yang
- Department of Biostatistics, University of Florida, Gainesville, FL
| | - Ira M. Longini
- Department of Biostatistics, University of Florida, Gainesville, FL
| | - M. Elizabeth Halloran
- Fred Hutchinson Cancer Research Center, Seattle, WA
- Department of Biostatistics, University of Washington, Seattle, WA
| | - Natalie E. Dean
- Department of Biostatistics, University of Florida, Gainesville, FL
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