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Rafferty AC, Bofkin K, Hughes W, Souter S, Hosegood I, Hall RN, Furuya-Kanamori L, Liu B, Drane M, Regan T, Halder M, Kelaher C, Kirk MD. Does 2x2 airplane passenger contact tracing for infectious respiratory pathogens work? A systematic review of the evidence. PLoS One 2023; 18:e0264294. [PMID: 36730309 PMCID: PMC9894495 DOI: 10.1371/journal.pone.0264294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 01/18/2023] [Indexed: 02/03/2023] Open
Abstract
We critically appraised the literature regarding in-flight transmission of a range of respiratory infections to provide an evidence base for public health policies for contact tracing passengers, given the limited pathogen-specific data for SARS-CoV-2 currently available. Using PubMed, Web of Science, and other databases including preprints, we systematically reviewed evidence of in-flight transmission of infectious respiratory illnesses. A meta-analysis was conducted where total numbers of persons on board a specific flight was known, to calculate a pooled Attack Rate (AR) for a range of pathogens. The quality of the evidence provided was assessed using a bias assessment tool developed for in-flight transmission investigations of influenza which was modelled on the PRISMA statement and the Newcastle-Ottawa scale. We identified 103 publications detailing 165 flight investigations. Overall, 43.7% (72/165) of investigations provided evidence for in-flight transmission. H1N1 influenza A virus had the highest reported pooled attack rate per 100 persons (AR = 1.17), followed by SARS-CoV-2 (AR = 0.54) and SARS-CoV (AR = 0.32), Mycobacterium tuberculosis (TB, AR = 0.25), and measles virus (AR = 0.09). There was high heterogeneity in estimates between studies, except for TB. Of the 72 investigations that provided evidence for in-flight transmission, 27 investigations were assessed as having a high level of evidence, 23 as medium, and 22 as low. One third of the investigations that reported on proximity of cases showed transmission occurring beyond the 2x2 seating area. We suggest that for emerging pathogens, in the absence of pathogen-specific evidence, the 2x2 system should not be used for contact tracing. Instead, alternate contact tracing protocols and close contact definitions for enclosed areas, such as the same cabin on an aircraft or other forms of transport, should be considered as part of a whole of journey approach.
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Affiliation(s)
- Anna C. Rafferty
- National Centre for Epidemiology and Population Health, The Australian National University, Canberra, Australian Capital Territory, Australia
- National Incident Centre, The Australian Government Department of Health, Canberra, Australian Capital Territory, Australia
| | - Kelly Bofkin
- Qantas Airways Limited, Mascot, New South Wales, Australia
- Virgin Australia Airlines, South Brisbane, Queensland, Australia
| | - Whitney Hughes
- Qantas Airways Limited, Mascot, New South Wales, Australia
| | - Sara Souter
- Qantas Airways Limited, Mascot, New South Wales, Australia
- Virgin Australia Airlines, South Brisbane, Queensland, Australia
| | - Ian Hosegood
- Qantas Airways Limited, Mascot, New South Wales, Australia
| | - Robyn N. Hall
- National Incident Centre, The Australian Government Department of Health, Canberra, Australian Capital Territory, Australia
| | - Luis Furuya-Kanamori
- UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Herston, Queensland, Australia
| | - Bette Liu
- School of Population Health, University of New South Wales, Kensington, New South Wales, Australia
| | | | - Toby Regan
- New Zealand Ministry of Health, Wellington, New Zealand
| | - Molly Halder
- New Zealand Ministry of Health, Wellington, New Zealand
| | - Catherine Kelaher
- National Incident Centre, The Australian Government Department of Health, Canberra, Australian Capital Territory, Australia
| | - Martyn D. Kirk
- National Centre for Epidemiology and Population Health, The Australian National University, Canberra, Australian Capital Territory, Australia
- National Incident Centre, The Australian Government Department of Health, Canberra, Australian Capital Territory, Australia
- * E-mail:
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Successful containment of a flight-imported COVID-19 outbreak through extensive contact tracing, systematic testing and mandatory quarantine: Lessons from Vietnam. Travel Med Infect Dis 2021; 42:102084. [PMID: 34048935 PMCID: PMC8149171 DOI: 10.1016/j.tmaid.2021.102084] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 04/15/2021] [Accepted: 05/12/2021] [Indexed: 01/12/2023]
Abstract
Background The importation of SARS-CoV-2 through air travel poses substantial risks to generate new COVID-19 outbreaks. Timely contact tracing is particularly crucial to limit onwards transmission in settings without established community transmission. Methods We conducted an in-depth analysis of the response to a big flight-associated COVID-19 outbreak in Vietnam in March 2020 that involved contact tracing, systematic testing and strict quarantine up to third generation contacts. Results 183 primary contacts from the flight as well as 1000 secondary and 311 third generation contacts were traced, tested, and quarantined across 15 provinces across Vietnam. The protracted confirmation of the index case at 3 days and 19 h after arrival resulted in isolation/quarantine delays of 6.8 days (IQR 6.3–6.8) and 5.8 days (IQR 5.8–7.0) for primary and secondary cases, respectively, which generated 84.0 and 26.4 person-days of community exposure from primary and secondary cases, respectively. Nevertheless, only 5 secondary cases occurred. Conclusions A large flight-related COVID-19 cluster was successfully contained through timely, systematic and comprehensive public health responses despite delayed index case identification. Multiagency collaboration and pre-established mechanisms are crucial for low and middle income countries like Vietnam to limit community transmission after COVID-19 importation through air travel.
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Maynard-Smith L, Brown CS, Harris RJ, Hodkinson P, Tamne S, Anderson SR, Zenner D. Effectiveness and outcomes of air travel-related TB incident follow-up: a systematic review. Eur Respir J 2021; 57:13993003.00013-2020. [PMID: 33214208 DOI: 10.1183/13993003.00013-2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Accepted: 10/27/2020] [Indexed: 11/05/2022]
Abstract
The World Health Organization (WHO) recommends following up passengers after possible exposure to a case of infectious tuberculosis (TB) during air travel. This is time-consuming and difficult, and increasingly so with higher numbers each year of flights and passengers to and from countries with high TB endemicity. This paper systematically reviews the literature on contact tracing investigations after a plane exposure to active pulmonary TB. Evidence for in-flight transmission was assessed by reviewing the positive results of contacts without prior risk factors for latent TB.A search of Medline, EMBASE, BIOSIS, Cochrane Library and Database of Systematic Reviews was carried out, with no restrictions on study design, index case characteristics, duration of flight or publication date.In total, 22 papers were included, with 469 index cases and 15 889 contacts. Only 26.4% of all contacts identified completed screening after exposure. The yield of either a single positive tuberculin skin test (TST) or a TST conversion attributable to in-flight transmission was between 0.19% (95% CI 0.13%-0.27%) and 0.74% (95% CI 0.61%-0.88%) of all contacts identified (0.00%, 95% CI 0.00%-0.00% and 0.13%, 95% CI 0.00%-0.61% in random effects meta-analysis). The main limitation of this study was heterogeneity of reporting.The evidence behind the criteria for initiating investigations is weak and it has been widely demonstrated that active screening of contacts is labour-intensive and unlikely to be effective. Based on our findings, formal comprehensive contact tracing may be of limited utility following a plane exposure.
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Affiliation(s)
- Laura Maynard-Smith
- National Infection Service, Public Health England, London, UK.,Hospital for Tropical Diseases, London, UK.,C.S. Brown and L. Maynard-Smith contributed equally to this article as lead authors and supervised the work
| | - Colin Stewart Brown
- National Infection Service, Public Health England, London, UK.,Dept of Infection, Royal Free Hospital, London, UK.,C.S. Brown and L. Maynard-Smith contributed equally to this article as lead authors and supervised the work
| | | | | | - Surinder Tamne
- National Infection Service, Public Health England, London, UK
| | | | - Dominik Zenner
- Institute for Global Health, University College London, London, UK
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Glasauer S, Kröger S, Haas W, Perumal N. International tuberculosis contact-tracing notifications in Germany: analysis of national data from 2010 to 2018 and implications for efficiency. BMC Infect Dis 2020; 20:267. [PMID: 32252650 PMCID: PMC7137477 DOI: 10.1186/s12879-020-04982-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 03/19/2020] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND International contact-tracing (CT) following exposure during long-distance air travel is resource-intensive, whereas evidence for risk of tuberculosis (TB) transmission during international travel is weak. In this study, we systematically analyzed the information from international requests for CT received at the national level in Germany in order to evaluate the continued utility of the current approach and to identify areas for improvement. METHODS An anonymized archive of international CT notifications received by the Robert Koch Institute between 2010 and 2018 was searched for key parameters for data collection. A total of 31 parameters, such as characteristics of TB patients and their identified contacts, were extracted from each CT notification and collated into a dataset. Descriptive data analysis and trend analyses were performed to identify key characteristics of CT notifications, patients, and contacts over the years. RESULTS 192 CT notifications, each corresponding to a single TB index case, were included in the study, increasing from 12 in 2010 to 41 in 2018. The majority of notifications (N = 130, 67.7%) concerned international air travel, followed by private contact (N = 39, 20.3%) and work exposure (N = 16, 8.3%). 159 (82.8%) patients had sputum smear results available, of which 147 (92.5%) were positive. Of 119 (62.0%) patients with drug susceptibility testing results, most (N = 92, 77.3%) had pan-sensitive TB, followed by 15 (12.6%) with multi-drug resistant TB. 115 (59.9%) patients had information on infectiousness, of whom 99 (86.1%) were considered infectious during the exposure period. 7 (5.3%) patients travelled on long-distance flights despite a prior diagnosis of active TB. Of the 771 contact persons, 34 (4.4%) could not be reached for CT measures due to lack of contact information. CONCLUSION The high variability in completeness of information contained within the international CT requests emphasizes the need for international standards for reporting of CT information. With the large proportion of TB patients reported to have travelled while being infectious in our study, we feel that raising awareness among patients and health professionals to detect TB early and prevent international long-distance travel during the infectious disease phase should be a cornerstone strategy to safeguard against possible transmission during international travel.
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Affiliation(s)
- Saskia Glasauer
- Institute for Medical Information Processing, Biometry and Epidemiology, Ludwig-Maximilians-Universität Munich, Munich, Germany
| | - Stefan Kröger
- Department of Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany
| | - Walter Haas
- Department of Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany
| | - Nita Perumal
- Department of Infectious Disease Epidemiology, Robert Koch Institute, Berlin, Germany.
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